Congress and meeting communications

César Menor Salván

May 2015

Summary The present volume includes research communications submitted by Dr. César Menor Salván to

congress, meetings and workshops and published in proceedings and books of abstracts. The list

is not comprehensive because, due to the lower relevance of congress communications outside

the meeting with respect to peer reviewed papers and the characteristics and number of

communications usually prepared by a researcher, some documentation is lost.

12th Biennial SGA Meeting12–15 AUGUST 2013, UPPSALA, SWEDEN

Mineral deposit research for a high-tech world

ProceedingsVOLUME 1

ProceedingsVolume 1

Edited byErik Jonsson et al.

12th Biennial SGA Meeting12–15 AUGUST 2013, UPPSALA, SWEDEN

Mineral deposit research for a high-tech world

SGA 2013 Programme

Scientific programme (see Table 1, p. xx for overview)

10.40-12.00 Aula, S3.5 Porphyry systems and epithermal deposits

Role of porphyry copper models in exploration and discovery. Richard H. Sillitoe

Hydrothermal alteration, SWIR-mineral mapping, vein distribution and age of the Haquira East porphyry Cu-Mo deposit. Federico Cernuschi, John H. Dilles & Robert Creaser

Fluid evolution in a super-giant porphyry Cu-Mo deposit: El Teniente, Chile. Jamie J. Wilkinson, Victoria H. Vry, Edward T. Spencer & José Seguel

10.40-12.00 room X, S3.1 Volcanic-hosted base and precious metal deposits Geochemical signature of the “zero-age chimney” formed on artificial hydrothermal vents created by IODP Exp. 331 in the Iheya North field, Okinawa Trough. Tatsuo Nozaki, Jun-ichiro Ishibashi, Kazuhiko Shimada, Yutaro Takaya, Yasuhiro Kato, Shinsuke Kawagucci, Takazo Shibuya & Ken Takai

Subseafloor structure of a submarine hydrothermal system within volcaniclastic sediments: a modern analogue for ‘Kuroko-type’ VMS deposits. Jun-ichiro Ishibashi, Youko Miyoshi, Hiroyasu Inoue, Chris Yeats, Steven P. Hollis, Juan C. Corona, Stephen Bowden, Shouye Yang, Gordon Southam, Yuka Masaki, Hillary Hartnett & IODP Expedition 331 Scientists

Hydrothermal systems related to intraoceanic arcs. Cornel E.J. de Ronde

10.40-12.00 room IX, S5 High-tech elements – deposits and processes

A new type of magmatic Sc-Zr occurrence located in the Kiviniemi area, Rautalampi, Central Finland. Tapio Halkoaho, Marjaana Ahven & O. Tapani Ramo

Carbonatite-hosted, late-stage apatite as a potential source of heavy rare earth elements? S. Broom-Fendley, F. Wall, A.E. Brady, A.G. Gunn, S.R. Chenery & W. Dawes

Granite-related indium mineralisation in SW England Jens C.O. Andersen, Ross J. Stickland, Gavyn K. Rollinson & Robin K. Shail

Indium fractionation in the granites of SW England. B. Simons, J.C.O. Andersen & R.K. Shail

10.40-12.00 room IV, S2.5 Ore mineralogy and geometallurgy A comparative automated mineralogical analysis of the Nkout (Cameroon) and Putu (Liberia) iron ore deposits. K.F.E. Anderson, G.K. Rollinson, F. Wall & C. J. Moon

Combining chemical analysis (XRF) and quantitative X-ray diffraction (Rietveld) in modal analysis of iron ores for geometallurgical purposes in Northern Sweden. Mehdi Parian & Pertti Lamberg

Geometallurgical characterisation of Ni-PGE ores through automated mineralogy. K.S. Viljoen, T. Dzvinamurungu, G. Mishra, D. Rose, F. van der Merwe, T. Greeff, M. Knoper, H. Mouri & H. Rajesh

Geometallurgical characterization of ore type B2 (high silica ore) at the Kiirunavaara iron ore deposit, northern Sweden. Kari Niiranen & Andreas Böhm

Isotope constraints on the genesis of the Arroyo Rojo VMS deposit (Tierra del Fuego, Argentina). Biel. C., Colás, V., Subías, I., Acevedo, R.D. & Bilström, K.

Geology and massive sulfide deposits in the Mofjell group in the Rodingsfjallet nappe complex, Nordland, Norway. Bjerkgard, T., Marker, M., Slagstad, T. & Solli, A.

Hydrothermal alteration and ore mineralogy at the Lombador massive sulphide orebody, Neves Corvo, Portugal: an on-going study. Joao RS Carvalho, Ana S Fernandes, Bruno B Moreira, Álvaro MM Pinto, Jorge MRS Relvas, Nelson Pacheco, Filipa Pinto & Ricardo Fonseca

Mineralogy, textures and new sulphur isotope data of the Cerro de Maimon VMS deposit ores, Dominican Republic. Joan Marc Colomer, Eloi Andreu, Lisard Torró, Joaquín A. Proenza, Joan Carles Melgarejo, Cevero Chavez, Ricardo del Carpio, Julio Espaillat & John F. Lewis

Hydrothermal alteration zonation in the massive sulfide-hosting footwall sequence of Lousal, Iberian pyrite belt. Ana S.C.Fernandes, Jorge M.R.S. Relvas & Joao X. Matos

The Jörn granitoid complex, Skellefte mining district, Sweden: petrography, lithogeochemistry and emplacement sequence. Manuel J. González-Roldán, Rodney Allen, Emilio Pascual, Teodosio Donaire, Manuel Toscano & Hans Årebäck

Hydrothermal imprint along the southern Central Indian ridge. K. U. Heeschen, U. Schwarz-Schampera , C. Bartsch, H. Franke, and F. Henjes-Kunst & J. Hansen

Petrochemistry and element mobility within the upper Tyrone arc, Northern Ireland: identifying VMS-prospective stratigraphic horizons. Steven Hollis, Stephen Roberts, Richard Herrington, Garth Earls & Mark Cooper

Recent advances in structural geology, lithogeochemistry and exploration for VHMS deposits, Kristineberg area, Skellefte District, Sweden. Nils F Jansson, Tobias Hermansson, Mac Fjellerad Persson, Alexandra Berglund, Annika Kruuna, Pietari Skyttä, Kai Bachmann, Jens Gutzmer, Reia Chmielowski & Pär Weihed

Structural investigation and 3D modelling of the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, Bergslagen region, south-central Sweden. Tobias C. Kampmann, Pär Weihed & Michael B. Stephens

Cu-Zn mineralisation at Vannareid, West Troms Basement Complex: a new Palaeoproterozoic VMS occurrence in the northern Fennoscandian Shield. V. Juhani Ojala, Harald Hansen & Hannu Ahola

Occurrence of gold (electrum) in the Lousal mine, Iberian pyrite belt, Portugal. Daniel P. S. de Oliveira, Carlos J. P. Rosa, Fernanda M. G. Guimaraes, Joao X. Matos, Zélia Pereira, Vasco C. S. Frias, Diogo R. N. Rosa & J. M. Castelo Branco

Major volcano-sedimentary facies types of the Madneuli polymetallic deposit, Bolnisi district, Georgia: implications for the host rock depositional environment. Nino Popkhadze, Robert Moritz, Stefano Gialli, Tamar Beridze, Vladimer Gugushvili & Sophio Khutsishvili

Observation on gold-copper mineralization at Noungou, Burkina Faso. Reinhard P. Ramdohr & Tatiana L. Evstigneeva

Alteration mineral domains under Loma la Cuaba: new insights as to the origin of the mineralization in the Pueblo Viejo district. Torró, L., Proenza, J.A., Melgarejo, J.C., Carrasco, C.A., Domínguez, H.S., Nelson, C. & Lewis, J.F.

Vascular plant materials control the formation of shale-hosted massive sulphides in the Iberian Pyrite Belt. Jesús Velasco-Acebes, César Menor-Salván, Sara Gismera-Díez & Fernando Tornos

S3.2 Sediment-hosted deposits Stable isotope studies of carbonate – hosted ore deposit in Cerro Minado, Huercal – Overa (Spain). Sandra Amores, Oriol Bertran, Ferran Buireu, Miquel Febrer, Joan Carles Melgarejo & Pedro Enrique–Gisbert

The silver-polymetallic Mangazeyskoe deposit (Russia, Sakha-Yakutia): evidence for an involvement of magmatic and basinal fluids from fluid inclusions and stable isotopes (C, O, S). Anikina E., Klubnikin G., Bortnikov N., Prokof’ev V. & Gamyanin G.

Vascular plant materials controls the formation of shale-hosted massive sulphides in the Iberian Pyrite Belt Jesús Velasco-Acebes*, César Menor-Salván, Sara Gismera-Díez and Fernando Tornos Centro de Astrobiología, CSIC-INTA, 28850 Torrejón de Ardoz, Madrid, Spain. *velascoaj@cab.inta-csic.es Abstract. The Iberian Pyrite Belt (IPB) is one of the biggest massive sulphide concentrations in the world. The mineralization lies within a sequence called Volcano-Sedimentary Complex, and it can be hosted by volcanic rocks (northern zone of IPB) or shales (southern one).

We propose that sulphides formation of southern part is due to paleogeographical changes and the onset of regional volcanism. Isotopic data of massive sulphides (-33.2 to +4.1 ) suggest that exists a second source of sulphur beside hydrothermal fluids, insomuch as stockwork presents a 34S between -2.5 to +10

New data of higher plant biomarkers indicate that biological crisis during D-C boundary was the responsible for the input of organic matter that sulphate-reducing bacterias used to supply the needed H2S to the basin. Keywords. Iberian Pyrite Belt, Tharsis, massive sulphides, biomarkers, geomicrobiology 1 Introduction. Geological setting The Iberian Pyrite Belt (IPB) belongs to the South Portuguese Zone (SPZ) and is located in the SW of the Iberian Peninsula. It is the largest volcanogenic massive sulphide province, with more than 80 massive sulphide deposits and 1750 Mt of ore (Sáez et al. 1996; Leistel et al. 1997; Tornos, 2006).

The stratigraphy of the IPB is rather simple. The basement is not exposed and the earlier most rocks are shale and sandstone of Famennian age, the PQ Group (>2000 m), deposited in a stable platform. The PQ Group is conformable overlain by the Volcano-Sedimentary Complex, which was deposited in an extensional marine continental basin, likely a back arc one. It includes two groups of volcanic rocks, alkaline to tholeitic basalt, and calc-alkaline andesite to rhyolite. These rocks occur as (crypto-) domes, flows and sills and are interbedded with abundant shale and chemical sediments, chert and massive sulphides (late Devonian-early Visean). The uppermost rocks are grouped in the Culm Group, a flysch-like sequence of Serpukovian-Bashkirian age that represents the infilling of the basin during the progradation of the Variscan front.

The massive sulphide deposits occur in both the northern and southern part of the Belt with different features. Those located in the northern IPB are invariably hosted by the apical part of felsic domes, in relationship with pumice- and glass-rich dacite to rhyolite of Early Tournaisian age. They are interpreted as being replacive and major examples include Aguas Teñidas, La Zarza or Aljustrel. The deposits in the southern IPB are much younger, of Strunian age, and exhalative on third order basins. This type includes deposits such as Neves Corvo,

Aznalcóllar-Los Frailes, Las Cruces, Lousal, Sotiel-Migollas, Valverde or Tharsis (Tornos, 2006).

Current models suggest that the massive sulphides of the southern IPB formed during the Devonian-Carboniferous boundary in response to major paleogeographic changes and the onset of volcanism in the area (Menor-Salván et al., 2010). In brief, crustal thinning and magmatism generated large hydrothermal cells synchronous with the accelerated diagenesis and dewatering of the PQ Group, which produced hydrothermal venting on the seafloor and formation of anoxic bottoms. Vented fluids were metal-rich but sulphur poor and the massive sulphides formed due to the input of large amounts of H2S derived from the biogenic reduction of seawater sulphate (Tornos, 2006; Tornos et al., 2008). This is consistent with the sulphur isotope values; different compilations of 34S data in the IPB show that the sulphur isotope values are more restricted and positive in the stockwork zones (-2.5 to +10 ) than in the overlying massive sulphides (-33.2 to +4.1 ), indicating that the deep sulphur-likely inherited from the sulphides in the PQ Group or due to the abiogenic reduction of seawater sulphate-mixed with another one derived with more negative signatures, likely the anaerobic sulphate reduction by chemolithoautrotrophic microbes in an open system to sulphate. Numerical modeling and isotope geothermometry suggest that the anoxic bottoms reached a steady state at temperatures around 60-110ºC, optimal for hyperthemophilic sulphate reducers.

The electron donor for reducing such a large amount of sulphate could be the organic matter supplied by the destruction of vascular plants in subaerial forests located nearby (Menor-Salván et al., 2010). Our goal is to provide possible evidences of the importance of terrigenous organic matter input in the flourishing of microbiological activity during the formation of the giant VMS deposits of the southern IPB. Two falsation criteria for our model are the lack of increase in higher plant molecular fossils coincident with the major inorganic geochemical changes and the lack of indicators of terrigenous organic matter input to the basin.

2 Higher plant indicators and related sulphide precipitation The Devonian-Carboniferous boundary is too a very important key when we talk about biomass destructions. The biological crisis lead to extinction of about 21% of marine genera and a general vanishing of microfauna (McLaren and Goodfellow, 1990; Sepkoski, 1996). The

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major biological crisis during DC boundary is called Hangenberg event, charactrized by geochemical, lithological and biological changes in all trophic levels, terrestrial and marine (Caplan and Bustin 1999). The paleoecological events during DC boundary could supplied the organic matter necessary to adjust the mass balance that explain the massive sulphide formation. We considered a simple biogeochemical reaction using anaerobic fermentation of hexoses as archetypical electron donor. Principal reactions to produce H2S are as follows:

C6H12O6 (glucose) + SO4

2- 2CH3COO- (acetate) + H2S + 2CO2 CH3COO- (acetate) + SO4

2- + 3H+ H2S + 2CO2 + 2H2O H2S + 0.5Fe2+ + 0.25O2 + + 0.5FeS2 (pyrite) + 0.5H2O

It is possible to combine some reactions to produce pyrite at the same time that CO2 is released:

C6H12O6 + 3SO4

2- + 1.5Fe2+ + 3H+ + 0.75O2 2 + 6CO2 + 7.5H2O

Clearest evidence for this reaction it is seen in Filón

Norte of Tharsis, inside the laminated ores composed by siderite-pyrite, interpreted as biogenic mounds (Tornos et al. 2008).

If this model is not correct, we should not find evidences of higher plant and terrigenous organic matter increase coincident with the mineralization event in the vertical distribution of biomakers.

Figure 1. Cadalene/1,3,6,7-tetramethylnaphthalene ratio and V/Cr ratio versus shale depth. The marked zone correspond with pyrite orebody.

With this null hypothesis, we found in the organic

extract of a shale sequence that cut the massive sulphide horizon, a strong increase in the cadalene relative concentration versus 1,3,6,7-tetramethylnaphthalene (Fig. 1), exactly coincident with the maximum increase of anoxicity (measured as V/Cr ratio) and the minimum

34S levels. 1,3,6,7-tetramethylnaphthalene has been selected because is a chemically similar molecule and its concentration remains constant along the entire sequence. Cadalene is a higher plant biomarker and its increase suggest a rise in the input of terrigenous organic materials.

Other higher plant indicator, that suggest the contribution of gymnosperm plants, is the 2-methylretene (Bastow et al., 2001). Enhanced level of this biomarker, corrected against 9-methylphenanthrene, confirm the major input of higher plant material (Fig.2) Figure 2. Vertical distribution of 2-methylretene/9-methylphenanthrene ratio versus shale depth. Marked zone represents the pyrite orebody.

Other evidences found are the enhanced levels of retene and 1-methylphenanthrene (measured as x/9-methylphenanthrene ratios). Taken together, this suite of biomarkers indicates high input of gymnosperm flora (Alexander et al. 1992). The retene/9-MP and 2-methylretene/9-MP ratios showed a linear correlation along the shale depth, confirming that both biomarkers are related and possibly from the same biological source.

The study of the linear hydrocarbons is a proxy for the evaluation of the input of terrestrial organic matter. The terrigenous/aquatic ratio (TAR, Peters et al. 2005) evaluates the proportion of C27-C31 n-alkanes versus lighter n-alkanes. Vertical distribution of TAR shows relative changes in the contribution of land flora versus marine input. As expected, we found a TAR increase in the interest zone, confirming the previous observation on aromatic terpene biomarkers ( Fig. 3)

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To confirm the information of n-alkane distribution, we evaluated the hopane/sterane ratio, measured as C30

-hopane/C29 sterane (Fig. 4). The increase of hopane/sterane ratio in the vertical distribution could suggest land input or/and aerobic bacteria rich facies. An increase in hopane together with anoxicity is a strong suggestion of bacterial rich land material, consistent with the vascular plant crisis during DC boundary.

Figure 4. Vertical distribution of hopane/sterane in Tharsis shale. Marked zone represents the pyrite orebody.

It is interesting to evaluate the paleovegetation changes associated with the orebody horizon. The lower retene/cadalene ratio in the interest zone suggests an ecological change with declining gymnosperm flora. The global dramatic increase in cadalene and abietane class biomarkers (retene and 2-methylretene), together with inverse variation in retene/cadalene ratio is suggestive of land ecosystem alteration, possibly destruction (Mizukami et al. 2013). Future prospects that confirm a dramatic destructive process of land biomass include the study of vertical distribution of high molecular weight PAHs, a proxy of paleofires. It is possible also that the ecological change was a gradual vascular plant crisis, consequence of climatic changes. The declining in vascular plants could increase erosion and incorporation of land materials to the marine basin, with concomitant increase of molecular biosignatures of land plants. Other

molecular evidence in this direction is the decrease of higher plant parameter (van Aarsen et al., 2000), that indicate a disminution of abietane-class terpenoid generating gymnosperm respect to global land flora (Fig. 5). 3 Conclusions The vertical distribution of land plant biomarkers, indicators or paleovegetation changes and indicators of terrigenous organic matter input showed a dramatic enhancement coincident with evidences of anoxia and strongly negative 34S levels. The organic and inorganic geochemical alteration coincides with the occurrence of shale hosted massive sulphide orebody.

Data suggests that the formation of massive sulphide orebody could be related with the major paleoecological changes during Devonian-Carboniferous boundary, Hangenberg event.

We interpret that these features could be applied to the rest of deposits in the southern domain in Iberian Pyrite Belt (IPB).

Figure 5. Vertical distribution of proxies of paleoflora

changes in the Tharsis shale sequence.

Acknowledgements Study funded by the project CGL 2011-23207.

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References Alexander R, Larcher AV, Kagi, RI, Price, PL (1992) An oil-source

correlation study using age-specific plant-derived aromatic biomarkers. In Biological Markers in Sediments and Petroleum; Moldowan, Albrecht and Philp ed. Prentice-Hall, NJ, USA.

Bastow, TP, Singh, RK, van Aarsen, BKG, Kagi, RI (2001) 2-methylretene in sedimentary material: a new higher plant biomarker. Organic Geochemistry 32: 1211-1217.

Caplan ML, Bustin RM (1999) Devonian Carboniferous Hangenberg mass extinction event, widespread organic-rich mudrock and anoxia: causes and consequences. Palaeogeography, Palaeoclimatology, Palaeoecology 148:187-207.

Leistel JM, Marcoux E, Thiéblemont D, Quesada C, Sánchez A, Almodóvar GR, Pascual E, Sáez R (1997) The volcanic-hosted massive sulphide deposits of the Iberian Pyrite Belt Review and preface to the Thematic Issue. Mineral Deposita 33:2-30.

McLaren, DJ, Goodfellow, WD, (1990) Geological and biological consequences of giant impacts. Ann. Rev. Earth Planet. Sci. 18:123 171.

Menor-Salvan C, Tornos F, Fernandez-Remolar D, Amils R (2010) Association between catastrophic paleovegetation changes during Devonian-Carboniferous boundary and the formation of giant massive sulphide deposits. Earth and Planetary Science

Letters 299:398-408. Mizukami, T, Kaiho, K, Oba, M (2013) Significant changes in land

vegetation and oceanic redox across the Cretaceous/Paleogene boundary. Palaeogeography, Palaeoclimatology, Palaeoecology 369:41-47

Peters, KE, Walters, CC, Moldowan, JM (2005) The Biomarker Guide, Vol II. Second Edition. Cambridge University Press, Cambridge, UK.

Sáez R, Almodóvar GR, Pascual E (1996) Geological constraints on massive sulphide genesis in the Iberian Pyrite Belt. Ore Geology Reviews 11:429-451.

Sepkoski, JJ, (1996). Patterns of Phanerozoic extinction: a perspective from global data bases. In: Walliser, O.H. (Ed.), Global Events and Event Stratigraphy in the Phanerozoic. Springer, Berlin, pp. 35 51.

Tornos F (2006) Environment of formation and styles of volcanogenic massive sulphides: The Iberian Pyrite Belt. Ore Geology Reviews 28:259-307.

Tornos F, Conde, C. and Spiro, B. (2008) Formation of the Tharsis Massive sulphide Deposit, Iberian Pyrite Belt: Geological, Lithogeochemical, and Stable Isotope Evidence for Deposition in a Brine Pool Economic Geology 103:185-214.

van Aarssen BGK, Alexander R, Kagi RI (2000) Higher plant biomarkers reflect palaeovegetation changes during Jurassic times. Geochimica et Cosmochimica Acta 64:1417-1424.

AROMATIC TERPENE BIOMARKERS REFLECTS PALEOECOLOGICAL CHANGES AT THE DEVONIAN-CARBONIFEROUS BOUNDARY IN THE

IBERIAN PYRITE BELT

César MENOR-SALVÁN*, Sara GISMERA DIEZ, Jesus VELASCO-ACEBES and Fernando TORNOS

Centro de Astrobiologia (CSIC-INTA). Ctra. Torrejón-Ajalvir km 4. 28850, Torrejón de

Ardoz, Spain *) Corresponding author: menorsc@cab.inta-csic.es

The Iberian Pyrite Belt represents one of the largest crustal sulphur anomalies, in the

form of one of largest concentrations of volcano-sedimentary massive sulphide deposits on

Earth. The massive sulfide deposits occur in both the northern and southern part of the Belt

with different features. Those located in the northern IPB are invariably hosted by the apical

part of felsic domes, in relationship with pumice- and glass-rich dacite to rhyolite of

Tournaisian-Visean age. Major examples include Aguas Teñidas, La Zarza or Aljustrel. The

deposits in the southern IPB, that comprises the giant depostist of Neves Corvo, Tharsis,

Aznalcóllar-Los Frailes, Las Cruces, Lousal, Valverde and Sotiel-Migollas, are hosted by

shale, exhalative and formed in anoxic third order basins (Tornos et al., 2008).The formation

of shale hosted massive sulfide deposits (363-359 Ma) was just before or coincident with the

Devonian-Carboniferous boundary. The inorganic geochemical data of the ore bearing

interval are consistent with ore formation during a highly anoxic event that was coeval with

the onset of submarine volcanism and major biological sulfate reducing activity, which

explain the decrease in 34S found in the ore bearing shale along D-C boundary. In a previous

work, we suggested that the source of electron donor that could explain the formation of

massive sulfide should be the enrichment of the basin in land organic matter (Menor-Salvan et

al., 2010). To elaborate this model, we measured the vertical distribution of aromatic

biomarkers and proxies for terrigenous/marine origin of organic matter along a continuous

sequence of shale. The sequence belongs to the lowermost Volcano Sedimentary Complex,

equivalent to the Tharsis orebody. The results showed a strong increase in cadalene/1,3,6,7-

tetramethylnaphthalene ratio and 2-methylretene/9-methylphenanthrene ratio (Fig.1)

coincident with the higher anoxicity (measured as V/Cr ratio) and lower 34S values on the

shale sequence, that corresponds with the D-C boundary. The values of HPI (higher plant

index, Van Aarsen et al., 2000), retene/9-methylphenanthrene and 1-methylphenanthrene/9-

methylphenanthrene showed similar feature. The increase in pristane/phytane ratio also

suggests an increase in terrestrial material to the basin, confirmed by a marked increase on

26th IMOGOrganic Geochemistry: trends for the 21st Century

- Vol. 2 -

Vol. 2, page - 291 -

25th International Meeting on Organic Geochemistry

IMOG 2011

18 - 23 September Interlaken, Switzerland

Book of abstracts

www.imog2011.com

The 25th

International Meeting on

Organic Geochemistry

Interlaken, Switzerland

18th – 23

rd September 2011

Book of Abstracts

IMOG 2011 Secretary, Rapiergroup, 113-119 High Street, Hampton Hill, Middlesex, TW12 1NJ, UK

email: IMOGsecretary@rapiergroup.com

2

Preface

Dear Conference Delegates,

The Book of Abstracts represents the work that will be presented at the 25th International Meeting on Organic Geochemistry, held in Interlaken, Switzerland from 18th – 23rd September 2011. The conference is organised under the auspices of the European Association of Organic Geochemists. A total of 586 abstracts were submitted for consideration by the Scientific Committee, of which most were accepted. Some abstracts were withdrawn during the process of preparation of the abstract volume, leaving 580 papers to be presented at the conference. The Scientific Committee selected 85 abstracts to be presented orally in either plenary or parallel sessions. In this volume, abstracts of the oral presentation are numbered from 1 – 85 with the prefix ―O‖. The remaining 495 abstracts were accepted as poster presentations and grouped in themed sessions. The posters will be split, with half on view for Monday and Tuesday and the remaining half on view for Wednesday and Thursday. Each themes session will be ―open‖ on a specific day, when the presenting author will be available for discussion. During this specific day the author should be in attendance during the poster session. Abstracts of posters are numbered from 001 to 516 with the prefix ―P‖. Posters P001 to P126 are open for discussion with the presenting author on Monday; P128 to P251 on Tuesday; P254 to P377 on Wednesday and P380 to P516 on Thursday. We hope that you will find this Book of Abstracts informative and wish you a successful and enjoyable conference.

ORGANISING COMMITTEE

Volker Dieckmann - Shell, The Netherlands (Conference Chairman) Erik Tegelaar - Shell, The Netherlands (Chairman Scientific Programme)

Pim van Bergen – Shell, Scotland Stefano Bernasconi, ETH Zurich, Switzerland

Michael Schmidt, University of Zurich, Switzerland Carsten Schubert, EAWAG, Switzerland

SCIENTIFIC COMMITTEE

Erik Tegelaar - Shell, The Netherlands (Chairman) Jan de Leeuw – Royal NIOZ and Utrecht University, The Netherlands

Sylvie Derenne - CNRS Paris, France Tim Eglinton - ETH Zurich, Switzerland

Francois Gelin - Total, France Vincent Grossi - University of Lyon, France Raymond Michels - CNRS Nancy, France

Richard Patience - Chevron, U.S.A. Ann Pearson - Harvard University, U.S.A.

Alex Sessions - CalTech, U.S.A. Tom Wagner - Newcastle University, U.K. Heinz Wilkes - GFZ Potsdam, Germany

215

P-071

Structural characterization of 1,6-dimethyl-5-isopentyltetralin from Cretaceous conifer fossil resins and coals: a novel

diterpene biomarker

Cesar Menor-Salvan1, Marta Ruiz-Bermejo1, Bernd R.T. Simoneit2

1Centro de Astrobiologia (INTA), Torrejon de Ardoz, Spain,

2Department of Chemistry, Oregon State

University, Corvallis, United States of America (corresponding author:menorsc@cab.inta-csic.es)

Recently, the gas chromatographic-mass spectrometry (GC-MS) study of the individual components of Cretaceous ambers (fossil resins) shown the presence of a previously unidentified compound with a molecular peak at m/z 230 (Pereira et al. 2009; Menor-Salvan et al. 2010). This compound, one of the main components of the extractable fraction of amber, is also common in the associated sediments, plant fossils and coals of the amber deposit. These authors suggested a 2,5,6-trimethyl-1-butyltetralin structure for the molecule, interpretation based largely in the fragmentation pattern observed in mass spectrum. In order to confirm this structure, we carried out the isolation and purification of the molecule from amber of the Cretaceous deposits located at Basque-Cantabrian Basin (Cantabria, Spain). For purification, the crude amber extract was fractionated by sequential elution in silica gel column followed by semi-preparative high performance liquid chromatography of the fraction containing the target compound and purity testing using GC-MS. The pure compound, a colorless oil, was then characterized by nuclear magnetic resonance (NMR). Using the NMR and fragmentation data, we could infer a 1,6-dimethyl-5-isopentyltetralin structure (Fig. 1) for the unknown compound, discarding the structure previously suggested in the literature. Fig. 1: Structure of 1,6-dimethyl-5-isopentyltetralin, isolated from Cretaceous amber. The biochemical precursors of this molecule are not identified, but taking into account the structures identified in the amber extracts and the preservation of original biomolecules, the origin of the 1,6-dimethyl-5-isopentyltetralin could be the oxidative degradation

of diterpenoids of the labdane class, as communic or agathic acids. The association with conifer fossil resins and the possible diterpene precursor suggest a coniferous botanical origin. Therefore, the presence of 1,6-dimethyl-5-isopentyltetralin in the sedimentary record could be indicative of conifer resin contribution to the organic matter. Spectroscopic characterization: 1H NMR (CDCl3, 400 MHz) δ 6.97 (s, 1H), 6.96 (s,

1H), 2.89 (m, 1H), 2.70 (m, 2H), 2.55 (m, 2H), 2.27 (s, 3H), 1.88 (m, 2H), 1.67 (m, 1H), 1.34 (m, 2H), 1.27 (d, J=7.02 Hz, 3H), 0.97 (d, J=6.25 Hz, 6H) 13

C NMR (CDCl3, 100 MHz) δ 140.3, 139.7, 134.8,

133.3, 127.8, 126.0, 38.2, 33.1, 31.1, 29.2, 27.4, 26.8, 23.6, 22.7, 20.8, 19.8. EI-MS m/z (%) 230 (M

+, 25), 215 (M-CH3, 14), 173

(29), 159 (100), 143 (13), 128 (12), 115 (7). References: Pereira, R., de Souza Carvalho, I., Simoneit, B.R.T., de Almeida Azevedo, D., 2009. Molecular composition and chemosystematic aspects of Cretaceous amber from the Amazonas, Araripe and Recôncavo basins, Brasil. Organic Geochemistry 40, 863-875. Menor-Salvan, C., Najarro, M., Velasco, F., Rosales, I., Tornos, F., Simoneit, B.R.T., 2010. Terpenoids in extracts of Lower Cretaceous ambers from the Basque-Cantabrian basin (El Soplao, Cantabria, Spain): Paleochemotaxonomic aspects. Organic Geochemistry 41, 1089-1103.

511

P-383

Accumulation and degradation of plastic pollutants and diisopropyl-naphthalenes during composting of organic

household waste

Cesar Menor-Salvan

Centro de Astrobiologia (INTA-CSIC), Torrejon de Ardoz, Spain (corresponding author:menorsc@cab.inta-csic.es)

Composting of household and urban organic waste received much attention by municipal authorities due to its utility in the recycling and volume reduction of waste. According with the waste management plan of the Spanish Government (Plan Nacional Integrado de Residuos 2007-2015, PNIR), in Spain, the 45-53% of

the solid urban waste are composed by food or gardening residues and most of these waste is processed in 65 composting plants that generated 720.000 tons of compost in 2006. This compost is used mainly for agriculture and gardening. Following this effort, the market of small units for homebrew compost using household waste increased in parallel with the ecological education of the public and now is a widespread practice. In spite, little attention has been received the molecular composition of compost (Spaccini and Piccolo, 2007). Also, the non-beneficial effects of application of compost on the soil quality or incorporation of contaminants to farm products is still not very well understood. In this sense, González-Vila et al (1999) noted the increase of phthalate esters in juice of tomatoes growth in compost-amended soils, together with changes in the lipid composition, suggesting a potential risk in the use of compost in the food industry. Following this line of evidence and the potential use of composting units as a model of concentration and early diagenesis of terpene biomarkers, the study of the organic solvent extractable fraction of compost, generated using household units, was carried out. For this study, a small compost unit (1,5 m

3) situated in an

urban environment was filled exclusively with food and gardening residues free of paper, plastic or non-compostable debris during five years. Yearly, samples of compost were extracted in dichloromethane/methanol 3:1 and analyzed by gas chromatography/mass spectrometry (GC-MS) Results and conclusion

The main single components of the extractable fraction of compost (mean 29.6% of total compost) is constituted by plant lipids, n-alkanes and plastic contaminants. The plastic contaminants found are dominated by phthalate esters, followed by 2,4.ditertbutylphenol and bisphenol A. Other relevant

anthropogenic compounds found are the diisopropyl-naphthalene isomers (DIPNs). The DIPNs could be accumulated in compost from the food residues, as consequence of migration from cardboard or paper packages (George et al. 2010; Sturaro et al., 1994). DIPNs and phthalates are effectively degraded during compost maturation: 15.4% of total extract after 1 year, 0.9 % after 5 years with only phthalates remaining. On the contrary, bisphenol A show resistance to degradation with accumulation on compost (0.1% of total extract after 1 year, 0.59% after 5 years). Further study is necessary in order to understand the fate of organic pollutants during composting and to evaluate possible risks of the use of poorly maturated composts in agriculture. References

George, S.C., Volk, H., Romero-Sarmiento, M.F., Dutkiewicz, A., Mossman, D.J., 2010. Diisopropyl naphthalenes: Environmental contaminants of increasing importance for organic geochemistry studies. Organic Geochemistry, 41, 901-904. González-Vila, F.J., Almendros, G., Madrid, F., 1999. Molecular alterations of organic fractions from urban waste in the course of composting and their further transformation in amended soil. The Science of Total Environment, 236, 215-229. Spaccini, R., Piccolo, A., 2007. Molecular characterization of compost at increasing stages of maturity. 1. Chemical fractionation and infrared spectroscopy. Journal of Agricultural and Food Chemistry, 55, 2293-2302. Sturaro, G., Parvoli, G., Rella, R., Bardati, S., Doretti, L., 1994. Food contamination by diisopropyl naphthalenes from cardboard packages. International Journal of Food Science & Technology, 29, 593-603.

Goldschmidt Conference Abstracts 2009 A368

Modelling the Sn and W evolution in peraluminous leucogranites from the

Central-Iberian Zone C. FERNANDEZ-LEYVA1*, C. RUIZ2 AND L. GONZALEZ1

1Geological Survey of Spain (l.gonzalez@igme.es) (*correspondence: c.fernandez@igme.es)

2Technical University of Madrid (UPM) Mining School, Spain (casilda.ruiz@upm.es) Leucogranites from Jálama Batholith show Sn and W

mineralizations [1] commonly related to peraluminous granitic magma systems [2]. Equilibrium and fractional crystallization models have been obtained for two extraction assemblages (Fig. 1). The comparison of the models with the original leucogranite data permits to establish two distribution trends: a magmatic trend, which represents Sn and W concentration and another one from W enrichment, not reproduced by the modelling.

Therefore magmatic process could explain Sn mineralization whereas W mineralization can not be attributing at the same process.

Figure1: Comparison of the models with the leucogranite data

[1] Ruiz et al. (2008) Chem. Erde 68-4, 337-450 [2] Haapala, I. (1997) J. Petrol., 38, 1645-1659.

Preservation under the Río Tinto extreme acidic conditions and a

potential location on Aram Chaos, Mars

DAVID C. FERNÁNDEZ-REMOLAR1, ELIZABETH JOHNSON2, TIM CLELAN2,

KIM LICHTENBERG2, CÉSAR MENOR-SALVÁN1, MARY SCHWEITZER2, RICARDO AMILS1, VICTOR PARRO1

AND RAY ARVIDSON1 1Centro de Astrobiología (INTA-CSIC), Ctra Ajalvir km 4,

28850 Torrejón de Ardoz, Spain (fernandezrd@inta.es) 2Marine, Earth & Atmospheric Sciences, North Carolina State

University, USA (eajohns2@ncsu.edu) 3Department of Earth & Planetary Sciences, Washington

University at St Louis, USA (lichtenberg@rsmail.wustl.edu) MER, Mars Express and MRO have provided evidence in

the form of sulfate deposits that some regions of Early Mars experienced episodic exposure to low-pH solutions. Spectral analysis shows the salts to be dominated by ferric oxides, with associated hydrated sulfates [1, 2]. Moreover, iron-rich caps appear topping different layers of this salty unit. This suggests that the cap may correspond to weathering horizons [1, 2], with dehydration and desulfation resulting in ferric oxide enrichment. A similar mechanism is observed in the acidic Rio Tinto system, where preservation of biological information can be traced over three terraces of different ages, and compared to that seen in the modern deposits of Río Tinto [3]. This results in deposition of a fine mineral coating over biological surfaces, where plant and animal tissues are permineralized and microbes are trapped inside ferric gels. Paleobiological analysis of each of the sucessive iron rich terraces demonstrates both morphological and compositional information is preserved, even in the 2 Ma deposits. Here we show a multi-disciplinary geobiological approach combining structural, mineral and molecular methods to characterize preserved biological markers. These data can then be used to optimize our search for signatures of extinct life in these Mars acidic materials.

This research is being supported through the Project ESP2006-09487 provided by the Research and Innovation Ministery of Spain. [1] Massé et al. (2008) JGR 113, doi: 10.1029/ 2008JE003131.[2] Lichtenberg (in prep.) JGR. [3] Fernández-Remolar & Knoll (2008) Icarus 194, 72-85.

Cold origins: Prebiotic Chemistry at the ice matrix

C. Menor-Salván

Centro de Astrobiología (CSIC-INTA). 28850 Torrejon de Ardoz, Spain. (cmenor@mtiblog.com / Fax: +34-949-327918)

Abstract

The ice world experimental model (i.e., the chemical

evolution in the range between freezing point of

water and the limit of stability of liquid brines, ≈273

to 210 K) is summarized. Overall, the ice matrix is an

adequate environment for the abiotic synthesis of

nitrogen heterocycles (including nucleobases).

1. Introduction

The origin of nucleobases and other heterocycles is a

classic question in the chemistry of the origins of life.

The construction of laboratory models for the abiotic

synthesis of nitrogen heterocycles in plausible natural

conditions also aids the understanding and prediction

of chemical species in the Solar System. If we

support the idea of a prebiotic origin of nucleobases,

a “cold origin of life” [1] or “ice world” is the

preferred prebiotic environment because the

nucleobases would be stable under cold conditions,

and such an environment supports the relevance of

eutectic water solutions of reactants in an ice matrix.

During the lasts years, we performed a series of

experiments [2,3] which demonstrate the feasibility

of the prebiotic synthesis of nucleobases at the ice

matrix in the range of existence of eutectic solutions

of organic solutes.

2. Results

The irradiation (by spark discharges or UV

irradiation) of an atmosphere containing methane/

nitrogen or acetylene, lead to the formation of

organic precursors whose fate depends on the

environmental conditions. If a water pool is present

at a temperature sufficiently low as freeze-thaw

cycles are set, products of atmospheric irradiation

could react with organic solutes, especially in the

concentrated brines formed during the freezing

process. The low temperature and freezing gives

different results from the classic prebiotic chemistry

simulations. Thus, the irradiation of a system

composed by methane-rich atmosphere and an ice

pool (Figure 1), lead to the concentration of

polycyclic aromatic hydrocarbons in water. If a

nitrogen solute is present in eutectic solutions, as

urea, the formation of pyrimidines (mainly uracil)

and purines (mainly adenine).

CH4 / N2

N

cyanoacetylene

ON

cyanoacetaldehyde

H2N

O

NH2

NH

ONH

O

uracil

N

N

OH

HO OH

2,4,6-trihydroxy pyrimidine

N OH

N

OH

N

HO

cyanuric acid

N

NH2

N

H2N N NH2

melamine

NH2

N

HO N OH

N

ammelide

NH2

N

HO N NH2

N

ammeline

C2H2

acetylene

CH•

phenyl

phenylethyne

HCN

N

N

NH2

N

HN

adenine

H2N

O

NH2

Triazines

Pyrimidines

Hydantoins

Amino acids?

Nitriles

Carbonyl

compounds

Aromatics

NH

ONH2N

cytosine

Figure 1: Summary of the products found by

prebiotic chemistry simulations based on

methane/nitrogen atmospheres and water in the

temperature range between -25ºC and the water triple

point. The cold conditions favor the formation of

nitrogen heterocycles.

If acetylene (a molecule that has received little

attention in the development of Prebiotic Chemistry)

is present in the atmosphere, its photolysis products

could react with efficient condensing agents, as urea,

leading to the efficient formation of nitrogen

heterocycles (Figure 2).

EPSC AbstractsVol. 9, EPSC2014-336, 2014European Planetary Science Congress 2014c© Author(s) 2014

EPSCEuropean Planetary Science Congress

Figure 2: Summary of the prebiotic chemistry of

acetylene in presence of urea eutectic solutions.

3. Summary and Conclusions

The cold prebiotic chemistry experimental model

could contribute to the understanding of chemical

evolution in cold water-rich planetary environments.

The experiments performed demonstrated that the

synthesis of aromatic hydrocarbons, purines and

pyrimidines and other nitrogen heterocycles of

potential prebiotic interest (such as triazines and

hydantoins) are favoured in the ice matrix by classic

cyanide and cyanoacetylene pathways or by

condensation of acetylene photolysis products.

Despite these results, the experimental prebiotic

chemistry in the solute-concentrated solutions that

fill the space confined by ice matrix has received

relatively little attention in the elaboration of the

models for the origin of organics in Solar System

bodies and prebiotic evolution. Consequently, it is

necessary to perform more experiments under

plausible prebiotic conditions, especially if

geochemical models support stable icy environments

on the prebiotic Earth. The ice world constitutes an

interesting prebiotic chemistry scenario that awaits

further investigation

References

[1] Eschenmoser, A.: Etiology of potentially primordial

biomolecular structures: from vitamin B12 to the nucleic

acids and an inquiry into the chemistry of life’s origin: a

retrospective, Angewandte Chemie (International Ed. in

English), vol. 52, pp. 12412–72, 2011.

[2] Menor-Salván, C., and Marín-Yaseli, M.R.: Prebiotic

chemistry in eutectic solutions at the water-ice matrix.

Chemical Society Reviews vol. 41, pp. 5404-5415, 2012.

[3] Menor-Salván, C., and Marín-Yaseli, M. R.: A new

route for the prebiotic synthesis of nucleobases and

hydantoins in water/ice solutions involving the

photochemistry of acetylene. Chemistry: A European

Journal, vol. 19, pp. 6488–97, 2013.

An electrochemical cell model of the origin of metabolism C. Menor-Salván

Centro de Astrobiología (CSIC-INTA). 28850 Torrejon de Ardoz, Spain. (cmenor@mtiblog.com / Fax: +34-949-327918)

Abstract

A dynamic system formed by the electrochemical

coupling of iron metal and iron-sulphur species,

derived from iron sulphide minerals, could promote

carbon fixation by reductive carboxylation of

thioacetate esters. Using a simple galvanic cell as

experimental approach, the results suggest that the

electrochemically active interfaces in plausible

geochemical conditions could drive a simple proto-

metabolism.

1. Introduction

One approach to the study of abiogenesis is the

hypothesis of a protometabolic, complex chemical

system that precedes the first living beings. The first

metabolic systems could emerged from the

interaction between sulphide minerals and/or soluble

iron-sulphide complexes and fluids rich in inorganic

precursors, which are reduced and derived from

crustal or mantle activity. The role of iron sulphur

proteins (which contain Fe-S clusters as active

centers in the electron transfer reactions) and their

occurrence in what are possibly the most primitive

steps of oxidation of organic substrates, the carbon

fixation by reductive carboxylation, and in the cell

energy transduction machinery, have been an

evidence used to connect the geochemical roots of

the origin of life to the origin of biochemistry [1].

The structural similarity between the biological iron-

sulphur clusters and the crystal structure of iron

sulphide minerals [2], the biomimetic activity of

synthetic soluble Fe-S clusters [3] and the highly

preserved biochemical reactions involved could

explain why Fe-S clusters are found in all biological

systems. In this sense, Fe-S clusters could trace the

origin of life to the iron sulphide minerals as the

roots of biochemistry [4]. In this work, we study the

possible connection between the biochemical

reductive carboxylation of thioesters and the

geochemistry of the iron-sulphide system, by

application of a new experimental approach: using an

electrochemical cell to simulate how gradients

between inorganic species could promote the

biomimetic carbon fixation.

2. Results

An electrochemical cell has been constructed using a

cylindrical graphite reactor filled with granulated

iron metal, a microporous clay barrier and pyrrhotite

wet paste formed by pyrrhotite powder, containing 1

mmol of sodium sulphide (pH 9) and, optionally, 1

mmol of hydroquinone. Previously, 1 mmol of ethyl

thioacetate was adsorbed by the pyrrhotite powder. A

graphite electrode inserted in the pyrrhotite

constitutes the cathode. The system was connected to

a power supply at 1.1 V under a nitrogen atmosphere.

The organic solutes were analysed after three days of

standing in anoxic conditions at room temperature;

the analysis shows a significant quantity of lactic

acid (Figure 1) with an estimated yield of 6.5% of the

added ethyl thioacetate. Pyruvic acid was also

detected, as well as glycolic acid and glycine.

1 2 . 5 0 1 3 . 0 0 1 3 . 5 0 1 4 . 0 0 1 4 . 5 0 1 5 . 0 0 1 5 . 5 0 1 6 . 0 0 1 6 . 5 0 1 7 . 0 0 1 7 . 5 0 1 8 . 0 0 1 8 . 5 00

1 0 0 0 0 0 0

2 0 0 0 0 0 0

3 0 0 0 0 0 0

4 0 0 0 0 0 0

5 0 0 0 0 0 0

6 0 0 0 0 0 0

7 0 0 0 0 0 0

8 0 0 0 0 0 0

9 0 0 0 0 0 0

1 e + 0 7

1 . 1 e + 0 7

T i m e - - >

A b u n d a n c e

T I C : M S C 2 3 . D \ d a t a . m s

Rela

tive

ab

un

da

nce

Retention time (min)

15 2012 24

Lactic acid

Pyruvic acid

Glycolic acid

Figure 1: Identified products obtained by

carboxylation of ethylthioacetate coupled to the

iron/pyrrhotite/sulphide electrochemical system. The

major formation of lactic acid could be explained by

reduction of newly formed pyruvic acid, catalysed by

iron sulphides [5]

EPSC AbstractsVol. 9, EPSC2014-111-1, 2014European Planetary Science Congress 2014c© Author(s) 2014

EPSCEuropean Planetary Science Congress

The control experiment without an external voltage

source shows a significantly lower yield in the

formation of lactic acid, suggesting that a low

potential electron donor could be necessary for the

process. To test this possibility, we performed an

experiment using the same electrochemical cell

design but without using an external voltage source

and adding 1 mmol of hydroquinone (Eº = −0.699V).

Hydroquinone can act as analog of the biological

ubiquinol and can perform electron transfer reactions

on the surface of minerals [6]. The model

biochemical reaction that motivates the selection of

hydroquinone as an electron donor is the formation

of pyruvate by direct carboxylation of acetic acid,

promoted by (quinone) pyruvate dehydrogenase. The

presence of hydroquinone promotes the synthesis of

lactic acid, increasing the yield to 10.5% and

suggesting that electrons can be transferred through

iron sulfur clusters or surfaces, similar to the

ubiquinol/iron-sulfur system in biochemistry. The

experiments performed suggest a model for the

reductive carboxylation of thioesters in abiotic and

non-enzymatic conditions (Figure 2). Also, an

electrochemical cell could be an approach to the

experimental study of Origin of Life, as are ideal for

the creation of electrochemical gradients and

simulate an electrochemically active geochemical

interface. Our work is the first experimental use of

electrochemical cells within the sphere of

abiogenesis and offers a potentially powerful model

through which to explore emergent biochemical

systems [5].

Figure 2: Reductive carboxylation of a simple

thioester, pulled by the iron-sulfur system

(pyrrothite/FeS/SH-) in an electrochemical cell. The

source of electrons is iron metal. Q: oxidized quinone;

HQ: reduced quinone.

3. Summary and Conclusions

Our experimental model shows that pyrrhotite

(Fe7S8), in a soluble sulphur-rich environment and in

the presence of soluble iron-sulphur clusters and

newly formed FeS mineral precipitates, whose

formation was induced by iron metal anodic

oxidation, can promote the reductive carboxylation of

simple thioacetic acid esters to form pyruvate/lactate

under mild conditions. The reaction could be

regarded as biomimetic of the pyruvate synthesis

promoted by pyruvate ferredoxin oxidoreductase

(PFOR) and favoured by the presence of low

potential electron donors, such as hydroquinone,

which suggests that the origin of ancient organic

cofactors boosted the emergence of simple

protometabolic systems. Overall, we showed

experimentally that iron sulphides could be coupled

with carboxylation in an emerging metabolism by

means of an electrochemical gradient.

References

[1] Beinert, H.: Iron-sulfur proteins: ancient structures, still

full of surprises, J. Biol. Inorg. Chem., Vol. 5, pp. 2–15,

2009.

[2] Russell, M.J., Martin, W.: The rocky roots of the

acetyl-CoA pathway. Trends Biochem. Sci. Vol. 29, pp.

358–363, 2004.

[3] Holm, R.H.: Electron Transfer: Iron–Sulfur Clusters. In

Comprehensive Coordination Chemistry II; McCleverty,

J.A., Meyer, T.J., Eds.; Pergamon: Oxford, UK, pp. 61–90,

2003.

[4] Russell, M.J.: The alkaline solution to the emergence of

life: energy, entropy and early evolution. Acta

Biotheoretica, Vol. 55, pp. 133–79, 2007.

[5] Ibañez de Aldecoa, A.L., Velasco, F. and Menor-Salván,

C.: Natural Pyrrhotite as a Catalyst in Prebiotic Chemical

Evolution. Life, Vol. 3, pp. 502-517.

[6] Kung, K. and Mcbride, M.B. Electron Transfer

Processes Between hydroquinone and iron oxides. Clay.

Clay Miner. Vol. 36, pp. 303–309, 1988.

Pyrrhotite catalyzes the synthesis of uracil under

hydrothermal conditions

A. L. Ibañez de Aldecoa and C. Menor-Salván

Centro de Astrobiología (CSIC-INTA), 28850-Torrejon de Ardoz, Spain (menorsc@cab.inta-csic.com)

Abstract

The hypothesis of a prebiotic origin for metabolic

cycles in hydrothermal systems gained interest

during last years. The experimental approach to

support this hypothesis was oriented mainly to the

formation of organic molecules in iron sulfide

mineral surfaces from inorganic precursors. In this

work, we explore the behavior of previously formed,

prebiotically plausible organic molecules in iron

sulfide rich, low temperature hydrothermal

environments. Using urea as a starting point, we

found that uracil and other nitrogen heterocycles

could be synthesized using water-urea solution as

precursor in a packed pyrrhotite bed reactor,

simulating hydrothermal conditions.

1. Introduction

Since the first proposals of a relationship between

hydrothermal systems and origin of life [1], the

experiments that replicate sulfide rich, hydrothermal

chemistry confirmed the potential of these systems

for the synthesis of organic molecules through carbon

fixation. The main role corresponds to ferrous sulfide

minerals [2]. These mineral phases can catalyze the

formation of organic compounds from CO and thiols

[3] in a hydrothermal environment, leading to the

hypothesis of the chemoautotrophic origin of

metabolism. About the role of this system in the

prebiotic chemistry of nucleic acid components, it

has been reported that iron sulfide minerals can

catalyze the formation of purines and pyrimidines by

formamide condensation [4]. We are interested in the

possible role of iron sulfide minerals in hydrothermal

environments in the prebiotic chemistry of organic

molecules regarded as prebiotic precursors, as urea,

amino acids and small organic acid. As an

experimental model, we designed a continuous flow

reactor with iron sulfide as immobilized phase and, in

a first approximation, presented here, we used

aqueous solutions of urea as nitrogen source and

tested if urea could be a source of nucleobases in iron

sulfide rich hydrothermal systems. Urea was selected

after its identification as a good precursor of

nucleobases in icy systems [5].

2. Materials and methods

2.1 Pyrrhotite

All pyrrhotite samples used were from the Gualba

quarries (Barcelona, Spain), a Fe-Cu (Mo-Pb-Zn)

sulfide rich skarn of Hercynian age. The pyrrhotite

was characterized by electron microprobe analysis

(EMPA-WDS) and X-ray diffraction (XRD). The

composition found is Fe9S10 with dominance of

hexagonal polytypes. The ore was selected from

metamorphic origin in order to minimize the content

of organic carbon. The Gualba pyrrhotite is strongly

ferromagnetic; this circumstance has been used to the

isolation of pyrrhotite from the ore paragenesis.

2.2 Experimental setup

The experiments were conducted using empty HPLC

25x0.25 cm steel columns, filled with pyrrhotite

powder. The powder was previously sterilized and

extracted using dichloromethane and methanol to

remove potential organic contaminants. The column

was connected to an HPLC pump using peek tubing

and connections. The pyrrhotite column was heated

at 120ºC and flow adjusted to maintain a constant

pressure of 200 bar (aprox. 0.1 ml/min). The aqueous

solutions (10 ml total) were previously filtered

through 0.22 microns filters and degassed. The

effluent of reactor was freeze-dried and organic

products were characterized using gas

chromatography-mass spectrometry (GC/MS) after

formation of trimethylsilyl derivatives.

3. Results

EPSC AbstractsVol. 8, EPSC2013-PREVIEW, 2013European Planetary Science Congress 2013c© Author(s) 2013

EPSCEuropean Planetary Science Congress

The formation of uracil was identified in a 0.1M

solution of urea flowed through pyrrhotite reactor,

with a yield of 3.5% of the total urea. The presence

of succinic acid, a common prebiotic molecule,

increased the uracil yield to 5.8%. The

supplementation of the urea solution with glyoxal

(0.1M) lead to the expected formation of hydantoin

and 2-oxo-4,5-dihydroxyimidazolidine as major

compounds, together with uracil, 5-

hydroxyhydantoin and succinic and fumaric acids

(Fig 1).

Figure 1: Synthesis of uracil and hydantoins from

urea catalyzed by pyrrhotite (FeS) under simulated

hydrothermal conditions.

To asset the mineral phase transformation, the worn

out pyrrhotite was studied by X-ray diffraction. The

new mineral phases identified were mainly pyrite,

followed by siderite and minor iron oxides.

4. Summary and Conclusions

This experiment could be added to those that

highlight the catalytic properties of iron sulfide

minerals in promoting prebiotic chemistry

transformations. The ferrous sulfide mineral can

catalyze the condensation of urea and/or urea and

succinic acid degradation products to form uracil in a

mechanism that still need to be elucidated. The

presence of other prebiotic molecules could increase

the organic diversity of the products. The presence of

glyoxal leads to the formation of hydantoins as main

product, together with uracil. The lack of other

pyrimidines or purines could be a consequence of the

extreme conditions of the system, which could

degrade other molecules more complex or labile. For

example, the potential cytosine could undergo rapid

deamination to uracil under these conditions. Uracil

remains in the system, as the most stable molecule of

the nucleobase related heterocycles. This is specially

highlighted by the use of urea as reactant, which, in

cold conditions, leads to the formation of a rich

assemblage of nitrogen heterocycles [5].

Acknowledgements

We thank the invaluable help of Frederic Varela

Balcells in the supply of pyrrhotite samples.

References

[1] Holm, N.G., ed.: Marine hydrothermal systems and the

origin of life, Origins of Life and Evolution of Biospheres,

Vol. 22, pp. 1-242, 1992.

[2] Wächtershäuser, G.: On the chemistry and evolution of

the pioneer organism, Chemistry and Biodiversity, Vol. 4,

pp. 584-602, 2007.

[3] Cody, G.D., Boctor, N.Z., Brandes, J.A., Filley, T.R.,

Hazen, R.M. and Yoder, H.S.: Assaying the catalytic

potential of transition metal sulfides for abiotic carbon

fixation, Geochimica et Cosmochimica Acta, Vol. 68, pp.

2185-2196, 2004.

[4] Saladino, R., Neri, V., Crestini, C., Costanzo, G.,

Graciotti, M., and Di Mauro, E.: Synthesis and degradation

of nucleic acid components by formamide and iron sulfur

minerals. Journal of the American Chemical Society, Vol.

130, pp. 15512–15518.

[5] Menor-Salván, C., Roig Marin-Yaseli, M.; A New

Route for the Prebiotic Synthesis of Nucleobases and

Hydantoins in Water/Ice Solutions Involving the

Photochemistry of Acetylene, Chemistry: a European

Journal, Vol. 19, pp. 6488-6497, 2013.

Ice world: the origin of nucleobases in ice-liquid water

coexistence conditions.

César Menor-Salván

Centro de Astrobiologia (CSIC-INTA), Torrejon de Ardoz, 28850-Madrid, Spain (cmenor@mtiblog.com)

Abstract

We could define the ice world as the chemical

evolution in the range between freezing point of

water and the limit of stability of liquid brines,

≈273 to 210 K. In this environment, the synthesis of

nitrogen heterocycles using urea as nitrogen source

and methane as precursor of active intermediates is

favorable from a prebiotic chemistry standpoint,

leading to a mixture dominated by pyrimidines and

hydantoins. Hence, the synthesis in ice matrix

constitutes an experimental model for the study of

origin of nucleobases in Solar System bodies.

1. Introduction

Despite the research into the photochemical

transformations in ice from an astrochemical point

of view, the study of the chemistry in the range of

stability of the ice–water interface has not received

much attention. This may be due to the scarcity of

the defined conditions in the Solar System during

the epoch of active prebiotic chemistry or the

difficulties for demonstrating that these cold

conditions existed in Hadean Earth. The evidence

for a liquid water subsurface ocean on Saturn’s

moon Europa[1] and the possible presence of

water-ammonia eutectic brines or even a subsurface

ocean in other outer giant planet satellites such as

Titan[2] rekindled the interest in liquid water

prebiotic chemistry. Moreover, the subsequent

proposed steps for the emergence of cellular life

have a limited temperature range, and a hot

prebiotic Earth was regarded to be an unlikely

environment for the origin of life by some

authors[4]. Miller and Orgel stated in 1974 that the

emergence of biological organization could only

occur at temperatures below the melting point of

the polynucleotide structure. After observing the

instability of organic compounds in the prebiotic

stages, these authors concluded that a temperature

of 273 K would have been beneficial and that

temperatures near the eutectic point of NaCl

solutions (251.3 K) would have been even better [5].

The low temperatures in planetary surface ices

could be more conductive to the origin and the

preservation of molecules that could be relevant for

the emergence of life. In 1994, in one of the first

explorations of the idea of an ice world-based

origin of the life raw materials, Bada et al. [6]

suggested that ice formations on early Earth could

have preserved organic compounds against

hydrolysis or photochemical degradation. Under

plausible planetary conditions, the presence of

liquid water at T<273 K within an ice matrix

creates a potential reactor where the synthesis or

polymerization of molecules of biological interest

could occur. Within this context, we proposed a

model of prebiotic synthesis in icy environments

that could favor the origin of nucleobases.

2. Methodology

The experimental setup and methods was detailed

previously [7], [8]. Briefly, pure water or urea

water solution in a sealed reactor under primordial

methane containing or acetylene containing

atmosphere, was subjected to freeze-thaw cycles in

a temperature range between 5ºC and the urea-

water eutectic point (-21ºC). The system was

energized by means of spark discharges or

ultraviolet irradiation (254 and 185 nm). Reaction

products were separated and identified using gas

chromatography-mass spectrometry.

3. Results

The sparking on a freezing dilute urea solution

under a nitrogen/methane atmosphere leads to the

formation of and cytosine, uracil as the main

identified pyrimidines, in addition to adenine

(Figure 1). The experiments showed that using the

freeze-thaw conditions, the observed sequence of

pyrimidine yield obtained was cytosine > uracil >

2,4-diaminopyrimidine > 2,4,6-trihydroxy

pyrimidine.

EPSC AbstractsVol. 8, EPSC2013-PREVIEW, 2013European Planetary Science Congress 2013c© Author(s) 2013

EPSCEuropean Planetary Science Congress

Figure 1. Origin of nitrogen bases in urea water-ice

solution under methane atmosphere.

The formation of cytosine as the main pyrimidine

suggests that the low temperature conditions could

reduce the rate of deamination to uracil and favour

subsequent chemical evolution steps. In our

analysis of the gas mixture obtained after sparking

a CH4/N2 mixture, the main product was acetylene,

followed by unsaturated hydrocarbons and HCN,

but no cyanoacetylene was found. To test if

acetylene could be a precursor of nucleobases, ice-

water urea system under pure acetylene atmosphere

were irradiated with ultraviolet radiation. The

reaction products (Figure 2) contained hydantoins,

pyrimidines and purines, including uracil, uric acid,

xanthine, guanine and adenine. The highest yields

corresponded to 5-hydroxyhydantoin,2-oxo-4,5-

dihydroxyimidazolidine, hydantoin, uracil,

parabanic acid and uric acid. Additionally, cytosine,

6-methyluracil and iso-orotic and orotic acids were

found in significant quantities. The presence of urea

inhibits the formation of acetylene photopolymers.

Figure 2: Acetylene as precursor of nucleobases.

Analysis of the reaction products suggests that

hydantoin was a product of direct synthesis from

acetylene derived glyoxal and urea. 5-

hydroxyhydantoin was a product of both direct

synthesis from glyoxylic acid and urea, and, in

lesser extent, from photodegradation of purines and

pyrimidines. The mechanism of formation of

purines is unclear, and the formation of ureido

derivatives of carboxylic acids could be implicated.

The water-ice matrix played a dual role as a

protective medium and a source of radicals for the

photo-oxidation of purines and pyrimidines.

4. Summary and Conclusions

The ice is a favorable matrix for the origin of

nucleobases and other organic molecules of

prebiotic interest, from precursors available in

primordial conditions, as urea and acetylene or

methane. The principal difference with prebiotic

chemistry in hot conditions is that, in ice free

environment, the atmospheric precursors tend to the

formation of tholins and photopolymers and the

inhibition of synthesis of nucleobases, which seems

to be strongly favored in the zone of coexistence of

ice and liquid water solutions enriched in organic

solutes.

References

[1] Chyba, C.F., and Phillips, C.B.; Europa as an abode

of life, Origins of Life and Evolution of the Biosphere,

Vol. 32, pp. 47-67.

[2] Tobie, G., Grasset, O., Lunine, J.I., Mocquet, A., and

Sotin C.; Titan internal structure inferred from a coupled

thermal-orbital model, Icarus, Vol. 175, pp. 496-502,

2005.

[4] Moulton, V., Gardner, P.P., Pointon, R.F., Creamer,

L.K., Jameson, G.B., and Penny, D.; RNA argues against

a hot start origin of life, Journal of Molecular Evolution,

Vol. 51, pp. 416-421, 2000.

[5] Miller, S.L., and Orgel, L.; The Origins of Life on the

Earth, Prentice Hall, New Jersey, 1974.

[6] Bada, J.L.; How life began on Earth: a status report,

Earth and Planetary Science Letters, Vol. 226, pp.1-15,

2004.

[7] Menor-Salván, C., Ruiz-Bermejo, M., Guzmán, M.I.,

Osuna-Esteban, S., Veintemillas-Verdaguer, S.; Synthesis

of Pyrimidines and Triazines in Ice: Implications for the

Prebiotic Chemistry of Nucleobases, Chemistry: a

European Journal, Vol. 15, pp. 4411-4418, 2009.

[8] Menor-Salván, C., Roig Marin-Yaseli, M.; A New

Route for the Prebiotic Synthesis of Nucleobases and

Hydantoins in Water/Ice Solutions Involving the

Photochemistry of Acetylene, Chemistry: a European

Journal, Vol. 19, pp. 6488-6497, 2013.

Origins2011 International Conference July 3rd–8th, 2011, Montpellier, France

A tholin with lactate dehydrogenase enzyme-mimic activity

César MENOR-SALVÁN*, Marta RUIZ-BERMEJO, Luis RIVAS, Susana OSUNA-ESTEBAN,

Sabino VEINTEMILLAS-VERDAGUER

Centro de Astrobiología (INTA-CSIC), Carretera Torrejón-Ajalvir Km 4.2, E-28850 Torrejón de Ardoz, Spain

* menorsc@cab.inta-csic.es

Several ways are possible to generate tholins (i.e. complex organic materials generated by irradiation of CH4,

CO or CO2 atmospheres, Sagan and Khare, 1979) by modification of physical conditions, composition or

energy sources. Generally, the hydrolysis or pyrolysis of tholins release single molecules as amino acids,

carboxylic acids or nitrogen heterocycles, but the nature and properties of their macromolecular structures

received comparatively lesser attention (McDonald et al., 1994). After the fractionation of tholins in a

hydrophilic and hydrophobic macromolecular fractions, we found that, despite its different chemical nature,

hydrophilic tholin share some physicochemical properties with polypeptides (Ruiz-Bermejo et al. 2008). In a

next step, we tested the ability of tholin to mimic intermediary metabolism reactions with prebiotic interest, a

role that could be relevant in the origin of the metabolism, following the idea of a protometabolism without

enzymes. In this sense, we show that some tholins generated by irradiation of CH4/N2 atmospheres could

mimic the lactate deshydrogenase (LDH) activity. This paleozyme (catalyst in a hypothetical non-enzymatic

origin of metabolism), could catalyze the oxidation of lactic acid to pyruvic acid, using NAD+ as electron

acceptor, in the same conditions of purified LDH-D from Lactobacillus leichmanii, selected by its low

activity and used as positive control. The dynamic light scattering and electrophoretic study of the active

tholin suggest that a tridimensional configuration analog to the tertiary structure of proteins could be the

basis of the catalytic activity.

6 8 10 12 14

Retention time

Ab

un

da

nce

(%

)

6 8 10 12 14

Retention time

Ab

un

da

nce

(%

)

A B

HO

O

OH

lactic acid

O

O

OH

pyruvic acid

Figure 1. Gas chromatogram showing lactate and the pyruvate synthesized using tholin exhibiting LDH mimic activity

(A) and a negative control performed in the same conditions using an inactive tholin (B).

References

Sagan C, Khare BN (1979). Tholins: organic chemistry of interstellar grains and gas. Science 277: 102–107.

McDonald GN, Thompson WR, Heinrich M, Khare BN, Sagan C (1994). Chemical investigation of Titan and Triton

tholins. Icarus 108: 137–145.

Ruiz-Bermejo M, Menor-Salván C, Mateo-Martí E, Osuna-Esteban S, Martín-Gago JA, Veintemillas-Verdaguer S

(2008) CH4/N2/H2 spark hydrophilic tholins: A systematic approach to the characterization of tholins. Icarus 198,

232-241.

Origins2011 International Conference July 3rd–8th, 2011, Montpellier, France

Magnetically induced enantioselective crystallization of sodium chlorate with hydrophobic amino acid impurities at the water-air interface

Susana OSUNA-ESTEBAN*, Maria Paz ZORZANO, César MENOR-SALVÁN, Marta RUIZ-BERMEJO, Sabino VEINTEMILLAS-VERDAGUER

Centro de Astrobiología (INTA-CSIC), Carretera Torrejón-Ajalvir Km 4.2, E-28850 Torrejón de Ardoz, Spain

*osunaes@cab.inta-csic.es

All the organic chemistry of terrestrial organisms is based on the L form of amino acids. Despite much effort devoted to elucidating how and why L-amino acids were preferentially selected with respect to the D-enantiomer no clear solution has yet been obtained. Some enantioselective mechanisms have been proposed however none of them deal with organic molecules in plausible prebiotic Earth environments.

In 1985 Gilat ( Gilat and Schulman 1985, Gilat 1985) proposed the existence of what he named “chiral interaction” between chiral biomolecules (such as amino acids) and a polar solvent (such as water), in the presence of an interface, that leads to the formation of a magnetic moment of opposite direction for each enantiomer. He also suggested that the geomagnetic field of the Earth may have interacted with this hypothetical magnetic moment inducing an energy difference between the two enantiomers. To validate this hypothesis, is necessary a technique that is sensitive to tiny amounts of chiral hydrophobic amino acids located only at the upper molecular layers of a water solution. We propose to use the crystallization of sodium chlorate (Osuna-Esteban et al. 2008) as a probe for plausible amino acid enantiomeric excesses (e.e.) at this interface. Our results indicate that an upwards pointing magnetic field induces a detectable L e.e. at the water-air interface, whereas a downwards pointing field induces a D excess in these environments. These experiments suggest that the geomagnetic field of the Earth may have played a significant role on the prebiotic origin of homochirality inducing an e.e. on all hydrophobic chiral amino acids participating in the ocean-atmospheric chemistry of the primordial aerosol cycle.

Figure 1. Hydrophobic amino acid at the air-water interface in L (left) and D (right) conformation, with the hydrophobic residue R sticking out of the water. The electric dipole field associated with the zweitterion induces around the molecule a loop current of solution cations and anions. This current produces a magnetic dipole µ (here indicated as a vector) which points upwards for the L enantiomer, and downwards for the D enantiomer.

References

Gilat G, Schulman LS (1985) Chiral interaction, magnitude of effects and applications to natural selection of L enantiomer. Chem. Phys. Lett. 121: 13-16

Gilat G (1985) Chiral interactions in biomolecules. Chem. Phys. Lett. 121: 9-12. Osuna-Esteban S. Zorzano MP, Menor-Salvan C, Ruiz-Bermejo M, Veintemillas-Verdaguer S (2008) Asymmetric

chiral growth of micron sized NaClO3 crystals in water aerosols. Phys. Rev. Lett. 100: 146102(4).

Origin of life in Fe-poor oceans under a CH4-rich and SO2-poor atmosphere: II. Experimental evidence. Cesar

Menor Salván1

and Hiroshi Ohmoto2.

1Centro de Astrobiologia, INTA-CSIC, Citra Ajahvir km. 4, 28850 Torrejón

de Ardoz, Spain, menorsc@inta.es. 2Penn State Astrobiology Research Center & Department of Geosciences, The

Pennsylvania State University, University Park, PA 16803, hqo@psu.edu.

Laboratory experiments carried out by various re-

searchers during the past decades have shown that or-

ganic synthesis by Miller-Urey reactions or related

mechanisms is not likely to have occurred if the pre-

biotic atmosphere was neutral or weakly reducing (i.e.,

CO2>CH4 N2>NH3, SO2>H2S, and H2>O2) Formation

of a significant amount of complex organic molecules

(i.e., tholins, amino acids, carboxylic acids, nitriles,

and hydrocarbons) in the atmosphere requires methane

as the main carbon bearing gas and an energy source

(e.g., sparks, plasma- and electromagnetic discharge,

and/or nuclear particles).

Our laboratory approach is consistent with theoreti-

cal investigations on the chemistry of pre-biotic atmos-

phere and oceans by Ohmoto and Menor-Salvan (see

the accompanying paper). The aim is to investigate the

fate of organic molecules, which were synthesized in

methane-rich atmospheres by spark discharges, in Fe2+

-

rich aqueous solutions. The atmospheres was varied in

the CH4/N2/H2 ratios: 100/0/0, 10/90/0, 30/70/0,

50/50//0, and 40/30/30. Temperature of the atmosphere

was thermostatized at room temperature. Organic

molecules formed in the atmosphere continuously fell

on a pool of liquid water (i.e., a simulated ocean) that

contained either 0 or 10 mM of aqueous Fe2+

. Tem-

perature of the “ocean” was regulated at 0, 25, or 50°C.

Aliquotes of the gas and solution were withdrawn

every 3 (or 5) hours and analyzed for compositions

using gas chromatography coupled with mass spec-

trometry. The chromatographic analysis was performed

using a Hewlett Packard PLOT/Q GC column installed

in a Turbomass Perkin Elmer GCMS system.

Our results indicate that the production of organic

molecules in the atmosphere was dependent primarily

on the partial pressure of CH4. However, for the pro-

duction of HCN, N2 is necessary. Dominant products in

the atmosphere acetylene and their volatile polymers

(diacetylene), unsaturated hydrocarbons (dominated by

ethylene, 1-propene, but-1-en-3-ine and 1,3-butadiine),

hydrogen cyanide, acetonitrile and acrylonitrile. Gas-

phase reactions were nearly completed in the first 3-5

hours, which were subsequently followed by the for-

mation of polymeric materials in aqueous or solid

phase when the water was free of iron.

In contrast, presence of iron (II) in solution is found

to destabilize hydrogen cyanide and acetylene that

formed in the atmosphere. A previous study in our

laboratory [1] showed that aqueous ferrous iron de-

creased the amounts of amino acids and polymeric ma-

terials which were formed by sparking meth-

ane/nitrogen/hydrogen atmospheres. Our results sug-

gest that the main reason for preventing the organic

molecules to increase polymerization in Fe-rich aque-

ous solutions is due to sequestration of cyanide by the

formation of iron ferrocyanide (Fe4[Fe(CN)6]3, Prus-

sian blue). Therefore, Fe2+

-rich oceans are not favor-

able environments for a chemical evolution scenario

based on atmospheric generation of organics. Further-

more, if the pre-biotic oceans had been Fe2+

-rich, most

of C and N in the atmosphere would have been se-

questred as ferrocyanide, which would have resulted in

reducing the amounts of C available for formation of

acetylene and other unsaturated hydrocarbons.

Results of our experimental study support the idea

that in an environment dominated by Fe-poor oceans,

the classical Urey-Miller based prebiotic chemistry in a

reducing atmosphere that was rich in CH4, N2 and H2

could be a significative contribution for the chemical

evolution and life emergence on Earth.

Reference: [1] Ruiz-Bermejo, M.; Menor-Salván,

C., Osuna-Esteban, S.; Veintenillas-Verdaguer, S. The

effects of ferrous and other ions on the abiotic forma-

tion of biomolecules using aqueous aerosols and spark

discharges. Orig. Life Evol. Biosph 37(6): 507-521

(2007)

5290.pdfAstrobiology Science Conference 2010 (2010)

ORIGIN OF LIFE IN FE-POOR OCEANS UNDER A CH4-RICH AND SO2-POOR ATMOSPHERE: I. THEORETICAL APPROACH. Hiroshi Ohmoto1 and Cesar Menor Salván2. 1 Penn State Astrobiology Research Center & Department of Geosciences, The Pennsylvania State University, University Park, PA 16803, hqo@psu.edu, 2Centro de Astrobiologia, INTA-CSIC, Citra Ajahvir km. 4, 28850 Torrejón de Ardoz, Spain.

Current popular theory for the pre-biotic Earth pos-

tulates a weakly reducing atmosphere (CO2>CH4 N2>NH3, SO2>H2S, and H2>O2), which would have prevented organic synthesis through the Urey-Miller related reactions based on CH4 as the carbon source. This theory was developed mostly on the assumptions that: (i) the atmospheric chemistry on early Earth was dictated primarily by volcanic emissions, (ii) composi-tion of the average volcanic gas has remained essen-tially the same throughout geologic history, and (iii) UV photolysis of volcanic SO2 produced the anoma-lous isotopic fractionation of sulfur (AIF-S) in Archean sedimentary rocks. Most geologists have also assumed that the Archean oceans were rich in Fe, derived by submarine hydrothermal fluids on mid ocean ridges, to produce banded iron formations.

However, recent geological and geochemical inves-tigations by various researchers have raised a serious question regarding the validity of these assumptions. For example, most H2O, C, N, and S on Earth may have been delivered >50 Ma after the accumulation of metals. Volcanic emission on the pre-biotic Earth probably occurred mostly under the oceans, rather than on land as today, because the land area was probably <20% of today. The typical fO2 values of pre-biotic magmas were probably 1±1 log unit below those of the fayalite+magnetite+quartz (FMQ) buffer, whereas those of modern subaerial volcanic gases are typically 1±1 log unit above FMQ. The AIF-S signatures in sedimentary rocks may have been produced by chemi-sorption reactions involving aqueous sulfate, H2S, or-ganic matter and a variety of minerals during the early diagenesis of sediments under hydrothermal condi-tions, rather than by atmospheric UV reactions.

Using thermochemical data, we have computed gas-fluid speciation in the H-O-C-S-N-Fe system as a function of T (1400-200°C), PH2O (1000-1 bar), and fO2 (FMQ-3 to FMQ+3); an important constraint on the sulfur chemistry is the presence of pyrrhotite (FeS) in most igneous rocks. The results suggest that vol-canic inputs to the pre-biotic atmosphere-ocean were dominated by reducing gases: H2>H2S>>SO2; CH4>CO2>CO; and NH3≈N2. We have demonstrated in the laboratory that Urey-Miller type organic synthe-sis readily occurs in atmospheres comprised of these reducing gases.

Our calculations also suggest that submarine hy-drothermal fluids contain excess H2S over heavy met-

als (= Fe+Cu+Zn+Pb) at T >~250°C. Mixing of such fluids with O2-poor pre-biotic oceans would have re-sulted in the precipitation of all the heavy metals as sulfides (and carbonates) at sites of fluid discharge, whereas significant amounts of Fe precipitates as goethite in modern oceans. The excess H2S from the submarine hydrothermal fluids would have reacted with oceanic basalts at lower temperatures to form additional FeS and FeS2. Therefore, the pre-biotic oceans were likely to have been poor in both Fe and H2S. This is important for the origin of life, because our laboratory experiments have shown that polymeri-zation of organic molecules to build complex organic molecules is inhibited by the presence of Fe2+ in water. The effects of Fe in organic synthesis will be further discussed in an accompanying paper by Menor Salvan and Ohmoto.

Our study supports the atmospheric-synthesis sce-nario proposed by Urey-Miller for the origin of life on Earth.

5473.pdfAstrobiology Science Conference 2010 (2010)

Goldschmidt Conference Abstracts A266

Critical influence of biogenic sulfur in the genesis of giant VHMS, Iberian

Pyrite Belt D.C. FERNÁNDEZ-REMOLAR

1, C. MENOR-SALVÁN1,

MARTA RUÍZ-BERMEJO1, RICARDO AMILS

1,2 AND

F. TORNOS3

1Centro de Astrobiología (INTA-CSIC), Ctra Ajalvir km 4, 28850 Torrejón de Ardoz, Spain (fernandezrd@inta.es)

2Centro de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Spain

3Instituto Geológico y Minero de España, c/Azafranal 48, 37001 Salamanca, Spain (f.tornos@igme.es)

During the late Devonian-early Carboniferous, the Iberian

Pyrite Belt was the loci of widespread hydrothermal activity and formation of volcanogenic massive sulfide deposits, making it the largest concentration of massive sulfides in the earth’s crust [1, 2]. The formation of these massive sulfides is currrently associated to subseafloor to seafloor precipitation by mixing of sulfur-depleted, metal-rich deep hydrothermal fluids of likely basinal derivation with seawater rich in biogenically derived reduced sulfur [2, 3]. Exhalative massive sulfides are better formed and preserved in anoxic oceanic bottoms, mainly three order basins filled with hydrothermal brines, i.e., brine pools [4]. The sulfides will result from the interaction of H2S, being produced through biogenic sulfur reduction, and the exhalated cations (H2S + M2+ → MS). This process demands reduced sulfur that can be mediated through Sulfur Reducing Bacteria. However, several questions remains unasked as the electron donor which would drive the reduction from SO4

= to H2S. The combination of several evidences as the presence of organics (including pristane and phytane), mineral association to siderite and microbial structures and the low δ34S values suggest that the massive sulfides were produced by microbial activity as proposed in [3] and can shed light in those biogeochemical processes involved in the sulfide production. [1] Leistel et al. (1998) Miner. Dep. 33, 2-30. [2] Tornos (2006) Ore Geol. Rev. 28, 259-307. [3] Tornos & Heinrich (2008) Chem. Geol. 247, 195-207. [4] Solomon et al. (2002) Geology 30, 87-90.

Cosmogenic-based physical and chemical denudation rates in the

Idaho Batholith KEN L. FERRIER

1,2, JAMES W. KIRCHNER1,3,4

AND ROBERT C. FINKEL

2,1 1Department of Earth and Planetary Science, University of

California, Berkeley, USA, 94720 (ferrier@eps.berkeley.edu, kirchner@eps.berkeley.edu)

2Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, 94550 (finkel1@llnl.gov)

3Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL), Birmensdorf, Switzerland

4Department of Environmental Sciences, Swiss Federal Institute of Technology (ETH), Zürich, Switzerland

Chemical weathering plays a prominent role in many

biogeochemical and geomorphological processes, supplying nutrients to soils and streams, promoting soil production, and drawing down atmospheric carbon dioxide. Rates of chemical weathering and physical erosion are thought to be coupled to one another, because rates of chemical weathering may depend on the rate at which physical erosion supplies fresh minerals to the soil, and rates of physical erosion may depend on the rate at which chemical weathering weakens bedrock and aids soil production. Several studies have found that chemical weathering rates are positively correlated with physical erosion rates, although the relationship varies substantially between studies.

Along two elevation transects in the deep, steep canyon of the South Fork of the Salmon River in the granitic Idaho Batholith, we have measured total denudation rates using 10Be concentrations in soil-borne quartz, and have split these rates into their physical and chemical components based on concentrations of chemically immobile zirconium in soil and parent rock. These rates are averaged over the long timescale of 10Be accumulation in soil-borne quartz, which at our field sites ranges from 5,000 to 26,000 years. Across our field sites chemical denudation rates (W) range from -5 ± 8 to 30 ± 4 t km-2 yr-1 and physical erosion rates (E) vary by more than a factor of four from 49 ± 4 to 218 ± 19 t km-2 yr-1. Most of our measurements are consistent with a power-law relationship between W and E, but several of the more rapidly eroding sites have slower chemical denudation rates than this relationship would predict, suggesting that chemical denudation rates at these sites may be damped by non-erosional factors (e.g., climate, vegetation) or that chemical denudation rates may in fact decrease as physical erosion rates approach limiting rates of soil production.

Goldschmidt Conference Abstracts

A620

Impact of sulfide separation on Ag and Mo budgets in arc magmas

M.J. MENGASON*, P.M. PICCOLI AND P.A. CANDELA

LMDR, Department of Geology, University of Maryland, College Park, MD 20742, USA (* correspondence: mengason@geol.umd.edu)

To understand the impact of sulfide separation on the

metal budgets of Ag and Mo in arc magmas, experiments have been performed on the partitioning of these metals among pyrrhotite, a rhyolitic melt, and an immiscible Fe-S-O liquid. Previous experimental work on the partitioning of pyrrhotite and chalcopyrite with respect to Cu and Au in magmatic settings relevant to intrusion-related hydrothermal ore deposits, show a strong potential for the depletion of these metals by the segregation of the sulfide phases from silicate melts [1, 2, 3]. This sequestration of metals in sulfides may play a role in determining the relative abundances of these metals in associated deposits, or possibly even preclude ore formation. Evacuated sealed silica tube experiments were performed at 1042°C, log fO2 between FMQ and NNO, and log fS2 = -1bar. Partition coefficients for Ag and Mo between pyrrhotite and silicate melt (Ag 58±8 [1σSDOM]; Mo 35±3), and between Fe-S-O liquid and silicate melt (Ag 120±20; Mo 90±10) have been determined. Uncertainties represent one standard deviation of the mean. Based on these values, limits may be placed on the proportion of the initial metal budget that may be removed by the segregation of these sulfides. During Rayleigh fractionation (F=0.1) where sulfides compose 0.1wt% of the assemblage, pyrrhotite would sequester Ag (13%) and Mo (8%) less effectively that the Fe-S-O melt (24% and 19% respectively). Although these reductions might lead to variations in the tenor of associated ore they appear to be unlikely to significantly inhibit ore formation on their own. However if the magma metal budget is augmented through interactions with other magmas or by the assimilation of reduced sulfide-bearing sediments, the effects would be enhanced. Under the same conditions with 0.3wt % sulfides, po could remove 33% of the Ag and 21% of the Mo, whereas Fe-S-O melts could remove 51% of the Ag and 46% of the Mo. This suggests that exogenous additions of sulfur to arc magmas can affect their ore metal budgets.

[1] Jugo et al. (1999) Lithos 46, 573-589. [2] Lynton et al. (1993) Economic Geology 88,s 901-915. [3] Simon et al. (2007) Geochimica et Cosmica Acta 71, 1764-1782.

Biomarkers preserved in fluid inclusions in quartz from the Berbes

fluorite deposit (N Spain) C. MENOR-SALVÁN

1, F. TORNOS2, M. RUIZ-BERMEJO

1, D. FERNÁNDEZ-REMOLAR

1 AND R. AMILS

1

1Centro de Astrobiología (INTA-CSIC), Ctra Ajalvir km 4, 28850 Torrejón de Ardoz, Spain (menorsc@inta.es)

2Instituto Geológico y Minero de España, c/Azafranal 48, 37001 Salamanca, Spain (f.tornos@igme.es)

The Cantabrian Zone in North Spain includes several

stratabound to vein-like fluorite deposits, forming a significant MVT district. The fluorite deposits replace Paleozoic limestone which are associated to an aureole of hydrothermal alteration including dolomitization and silicification. They are interpreted as formed from the reaction of deep basinal brines with limestone, with some mixing with coeval seawater. The outer hydrothermal aureole includes abundant euhedral quartz crystals hosting abundant and large fluid inclusions that are frequently infilled with hydrocarbons. The analysis of the hydrocarbons reveals the presence of biomarkers: acyclic isoprenoids, polycyclic isoprenoids and fatty acid esters. Specifically, we found squalene, phytol and phytene, evidencing low maturation of organics.

Figure 1: GC/MS chromatogram (total ion count) of hydrocarbon inclusions in quartz from Berbes. Sq: squalene.

These results suggest that the hydrocarbons included in

quartz source well preserved biomarkers which be of great interest for early Earth biosphere and planetary studies.

The genesis of these hydrocarbons is probably related with (a) dolomitization of the host rocks, or (b) hydrothermal degradation of underlying shale. Speculative, these processes would lead to the formation of nearby gas and oil fields.

Sq

Hopanoids

Phytol

Wax esters

European Astrobiology Network Association2006 Meeting

EANA – European Astrobiology Network Association

16–18 October 2006Lyon, France

Early Earth

Why on Earth?F. AlbaredeLST, Ecole Normale Superieure de Lyon, 46 Allee d’Italie, 6964 LyonCedex 7, France, e-mail: albarede@ens-lyon.fr

The most troubled period of Earth’s history extends from the end of

planetary accretion to the onset of plate tectonics: it is certainly the

most important for understanding the origin of life but also still the

most confusing for its near complete lack of observations.

Fundamental uncertainties arise both with the sequence of geodynamic

processes that eventually lead to the triumph of plate tectonics and life

and with the timing of events. The first issue is the very existence of a

terrestrial magma ocean. The upper mantle of the early Earth must

have been molten to depths in excess of 500 km by the release of the

gravitational energy of planetary accretion, which includes the Moon-

forming impact and core segregation. However, this concept has been

broadly rejected by geodynamicists for over 15 years on the ground

that the major solid silicates (olivine, pyroxenes, and garnet) are denser

than the magmas they crystallize from, while the role of buoyant

plagioclase remains limited by the strong gravitational field of the

Earth. This view holds that barren magma exposed to the surface

quickly looses its heat by radiation into space and the Earth freezes in

less than a million years. Evidence of 142Nd anomalies created by the

extinct radioactivity of 146Sm (T1/2=103 My) gathered over the last

three years showed this view to be incorrect and that a molten mantle

existed until some 30 My after the formation of the nebula, a timing

which happens to coincide with core segregation. The crux is likely to

be the presence of a hydrosphere, which is unlikely to originate by

outgassing of the Earth’s magma ocean: terrestrial material lost most

of its volatile elements (e.g. 85% of its K) and the interior of the planet

certainly emerged bone-dry from the early stages of accretion. Water

was therefore introduced from the outer Solar System at a late stage by

the perturbing effect of giant planets on the orbits of icy objects. Water

reacts with magmas and solid rocks to form hydrous minerals with low

densities (serpentine, talc, and amphibole), which accumulated as a

protective crust. Such a conductive boundary layer on top of the

magma ocean extended the life of the magma ocean by a few tens of

millions of years. An additional characteristic of the presence of water

is the massive liberation of H2 upon oxidation of ferrous iron and its

ensuing reaction with CO2 to produce CH4 and NH3. A remarkable

incidence of these processes on the origin of life is the formation of pre-

biotic molecules. A second issue is how and when the Earth’s dynamic

regime morphed into plate tectonics (or at least some early form of it)

and why it did not bifurcate into a Mars-type regime of a thick litho-

spheric lid stagnant over the convective mantle, a situation far less

propitious to create a biotic environment. Abundant granites are the

hallmark of plate tectonics because they cannot be melts of the mantle

and necessitate wet basalts as source rocks. Zircons are ubiquitous in

granites but are highly soluble in basaltic melts. The discovery of

4.0–4.4 Gy old zircons in Jack Hills sandstones (Australia) therefore

appears as smoking-gun evidence that at least some true granites

existed, while their 176Hf isotope compositions indicate that the source

of these granites (presumably hydrous basaltic rocks) formed very

early in the Earth’s history. Continents rising above sea level constitute

the major renewable source of nutrients (nitrate, phosphate) essential

to maintaining life. This does not necessarily mean that continents

were as widespread then as they are today and the case has recently

been made that the rise of chlorophyll stepped up the capture of Solar

energy, thereby increasing the rate of weathering and indirectly affec-

ted the rate of continental crust production. Conservatively, the point

can be made that some continental crust existed by 4.3 Gy and that ‘a

lot’ of it had come into existence by the time of the Isua rocks (3.85 Gy

ago). Plate tectonics and life share water as a common thread, and

water owes its presence on Earth to the strong gravitational field of the

planet.

From suns to life : a chronological approach to thehistory of life on EarthM. Gargaud(1), D. Despois(1), F. Albarede, J. C. Augereau, L. Boiteau,M. Chaussidon, P. Claeys, E. Douzery, P. Forterre, M. Gounelle,A. Lazcano, H. Martin, M. Marty, P. Lopez-Garcıa, M. C. Maurel,T. Montmerle, A. Morbidelli, D. Moreira, R. Pascal, D. Pinti,J. Pereto, D. Prieur, J. Reisse, F. Selsis, M. Van Zuilen(1) Observatoire Aquitain des Sciences de l’Univers, L3AB, BP89,33270 Floirac, France, e-mail: gargaud@obs.u-bordeaux1.fr

We present, in a synthetic chronological frieze, the various events

considered by the authors as relevant to the origins of life on Earth.

These events have been tentatively ordered chronologically in accord-

ance with actual knowledge within all the scientific disciplines involved

in astrobiology. This frieze was originally published in November 2006

in a topical issue of Earth, Moon and Planets1 gathering nine articles

written by 25 scientists (astronomers, geologists, biologists, and chem-

ists) who have attempted to share their specialized knowledge con-

cerning a common question: How did life emerge on Earth? Their

ultimate goal was to provide an initial answer as a prerequisite to an

even more demanding question: Is life universal? By adopting a

chronological approach to the question of the emergence of life on

Earth (the only place where we know for sure that life exists, even

though nobody agrees on the general definition of ‘ life ’), it was poss-

ible to break down this question into several sub-questions that can be

addressed by different disciplines. After an introduction, the main

chapters of this review cover the following: the formation and evol-

ution of the Solar System; the building of an habitable planet; pre-

biotic chemistry, biochemistry, and the emergence of life ; the

environmental context of the early Earth; the ancient fossil record and

early evolution. The concluding chapter summarizes the highlights of

International Journal of Astrobiology 6 (1) : 59–87 (2007) Printed in the United Kingdom

doi:10.1017/S1473550407003679 f 2007 Cambridge University Press

59

and simulated Mars conditions. The methanogenic archaea in pure

cultures as well as in their natural environment of the Siberian perma-

frost represent high survival potential under these extreme conditions.

In contrast, these conditions were lethal for the reference organisms

from non-permafrost habitats1,2. Our data suggest that in the scenario

of subsurface lithoautotrophic life on Mars methanogenic archaea

from Siberian permafrost could be used as an appropriate candidates

for possible life on Mars.1 Morozova, D. & Wagner, D. (2006). Stress response of methanogenic

archaea from Siberian permafrost compared to methanogens from non-

permafrost habitats. FEMS Microbiol. Ecol. (submitted).2 Morozova, D. et al. (2006). Survival of methanogenic Archaea from

Siberian permafrost under simulated Martian thermal conditions.

Origins Life Evol. Biosph. (in press).

Halophiles from rock salt – a promising model for thesearch for extraterrestrial life?G. W. Weidler, F. W. Gerbl, M. Pfaffenhuemer, C. Gruber,H. Stan-LotterUniversity of Salzburg, Department of Molecular Biology, Divisionof Microbiology, A-5020 Salzburg, Austria, e-mail:gerhard.weidler@sbg.ac.at

Halophiles isolated from Permian rock salt might be promising model

organisms for the search for extraterrestrial life, owing to the discovery

of halite in meteorites, salts on Mars and the fact that several viable

microorganisms have been isolated from Permo-Triassic rock salt (age

195 to 250 million years)1. In most cases these strains belong to the

extremely halophilic Archaea. Two major strategies for the estimation

of microbial community composition in ancient rock salt were used.

First, diversity was determined by molecular methods such as 16S

rRNA gene amplification, clone library construction and phylogenetic

analysis2. Second, a culture-dependent approach was started in 1999

with rock salt obtained from alpine salt mines. In this work 135 isolates

have been examined with restriction fragment length polymorphism

(RFLP) analysis of 16S rRNA gene fragments and with pulsed field gel

electrophoresis (PFGE), as well as S1 Nuclease-PFGE to identify

putative megaplasmids. It was possible to arrange all isolated strains

into three groups according to RFLP patterns. Two RFLP groups were

closely related to Halococcus sp. and one group was related to

Halobacterium sp. PFGE and S1-PFGE analyses showed, according to

whole genome restriction analysis and the presence of putative mega-

plasmids, that diversity is broader than RFLP analysis showed. Our

results show that the diversity of cultivable organisms is, as expected,

small, but examination of isolates by molecular methods showed that

the closely related strains are more diverse than previously thought.1 Stan-Lotter, H. et al. (2003). Int. J. Astrobiol. 1(4), 271–284.2 Radax, C., Gruber, C., Stan-Lotter, H. (2001). Extremophiles 5,

221–228.

Growth of microorganism populations underexperimental modelling of Martian and cometarynucleus subsurface conditionsA. K. Pavlov(1,3), V. N. Shelegedin(2), M. A. Vdovina(1),A. V. Tretyakov(1)(1) Ioffe Physico-Technical Institute, St. Petersburg, Russia, e-mail :mariya.vdovina@mail.ioffe.ru; (2) St. Petersburg Polytechnical StateUniversity, St. Petersburg, Russia; (3) Russian Astrobiology Center,St. Petersburg, Russia

Modern environmental conditions on Mars and cometary nuclei pro-

hibit the existence of liquid water on the surface layer of Martian soil

and cometary mantles because of extremely low atmospheric pressure.

However, according to observational data, a large amount of water ice

is present in the Martian and cometary subsurface. In both cases the ice

is subject to intensive sublimation if the surface is heated by Sunlight.

The surface layer which diffusion goes through is a porous material

with a poor admixture of organic matter for Mars and high admixuture

of organic for comets. In our experiment, we used a special vacuum

chamber in order to model the process of ice sublimation and vapour

diffusion under heating. In order to model these processes we used a

water ice sample covered by several centimetres of sand containing or-

ganic matter. Intensive sublimation was provided by radiation heating

of the sand’s surface. We studied the possibility of the active growth of

microorganisms in the vapour diffusion layer. Bacteria Vibrio sp. X

were added to the sand. We performed several three-day experimental

runs of the intensive sublimation of ice. As a result, we have recorded

an increase of the bacterial population after each run. These results

confirm the possibility of active metabolism and even reproduction of

microorganisms under Martian and cometary surfaces.

Application of Solid-Phase Micro-Extraction (SPME)in the analysis of biomarkers in geological samplesC. Menor-Salvan, M. Ruiz-Bermejo, S. Osuna-Esteban,S. Veintemillas-VerdaguerNational Institute for Aerospace Technology (INTA), Spain, e-mail:menorsc@inta.es

Biomarkers are organic indicator compounds that could be used as

tracers for geological and environmental processes1. These organic

compounds can unambiguously be linked to a known biological pre-

cursor and include mainly hydrocarbons (derived from lipids and pig-

ments), fatty acids and long-chain ketones and alcohols. Authors

usually use the solid–liquid extraction of the samples as separation step,

prior to the analysis of biomarkers by instrumental and chromato-

graphic techniques. The properties of biomarker compounds are ap-

propriate for the use of SPME as preparative step in the analytical

process. It is a solvent-free technique that enables extraction and con-

centration steps simultaneously, using small quantities of the rock or

sediment sample and allows the later application of classic extraction

techniques in the same sample. SPME, coupled with GC-MS, has a

higher efficiency and sensitivity than classic liquid extractions, reduces

the process time and increases the cleanness of the technique. We used

the SPME technique successfully for the organic analysis of natural

samples with different geology and age and we found it applicable in the

routine organic speciation of geological samples.1 Simoneit, B. (2005). Mass Spectrom. Rev. 24, 719–765.

Light- and electron-microscopic analysis ofHaloarchaea embedded in Austrian rock saltM. Dornmayr-Pfaffenhuemer(1), T. J. McGenity(2), M. N. Spilde(3),P. J. Boston(4), H. Stan-Lotter(1)(1) Department of Molecular Biology, University of Salzburg,Billrothstrasse 11, 5020 Salzburg, Austria, e-mail:marion.pfaffenhuemer@sbg.ac.at; (2) Department of BiologicalSciences, University of Essex, Colchester CO4 3SQ, UK; (3) Instituteof Meteoritics, MSC03 2050, 1 University of New Mexico,Albuquerque, NM 87131-0001, USA; (4) Department of Earth &Environmental Science, New Mexico Tech, Socorro, NM 87801, USA

Subsurface salt mines, such as those in Bad Ischl and Altaussee,

Austria, are examples of sites where extremophilic microorganisms can

be found. The most recent isolates from these salt mines areHalococcus

dombrowskii1 and Halobacterium noricense2. In order to understand

how these microorganisms are able to survive long periods of time

embedded within sediments it is necessary to analyse the fine structures

and the average chemical composition of the minerals where they were

isolated. In this study a JEOL 8200 Electron Microprobe and a JEOL

5800LV SEM equipped with an Oxford Analytical ultrathin-window

EDS and an Oxford Isis 300 X-ray analyser were used to analyse the

ultrastructure and chemical composition of 250 million year old rock

salt. The mineral structures, which occur at grain boundaries and in

fluid inclusions, were examined for their significance as possible mi-

crobial habitats. In addition, haloarchaeal cells were embedded within

salt crystals under laboratory conditions and subsequently analysed by

light microscopy. The mineral structures of the ancient rock salt were

examined for their significance as possible microbial habitats. Liquid-

filled structures such as clay particles, fluid inclusions and grain

boundaries are present; the chemical analysis of the liquid composition

EANA 2006 Lyon Abstracts 69

temperatures below 500 xC in several active tectonic settings.

Biogeochemically, the process is important because it leads to reduction

of H2O to H2. At the same time, catalytically active compounds such as

magnetite are formed. H2 may be used together with CO2 andmagnetite

as a catalyst in Fischer–Tropsch Type (FTT) reactions. FTT processes

may lead to the formation of CH4 as well as heavier hydrocarbons and

other abiotic organic compounds. Serpentinization at temperatures

below 300 xC is associated with high pH (pH 10–12). It is possible

that the high pH may promote the formose reaction in natural en-

vironments and the abiotic formation of pentoses such as ribose,

the carbohydrate constituent of RNA. Pentoses, and ribose in par-

ticular, are stabilized by borate that is scavenged from seawater by

brucite – magnesium hydroxide that is yet another product of ser-

pentinization reactions.

Origin of homochirality in an early peptide worldA. Brandenburg(1,2), H. Lehto(1,3), K. Lehto(1,4)(1) Nordita, Blegdamsvej 17, DK-2100 Copenhagen, Denmark, e-mail :brandenb@nordita.dk; (2) AlbaNova University Center, 10961Stockholm, Sweden; (3) Tuorla Observatory and Physics Department,University of Turku, Finland, e-mail: hlehto@utu.fi; (4) PlantPhysiology and Molecular Biology Laboratory, University of Turku,Finland, e-mail: klehto@utu.fi

Life on Earth has chosen one of two possible chiral forms: amino acids

left handed, and sugars right handed. Life may very well have been the

other way around, and maybe it is actually the other way for some alien

life forms still to be discovered. In our talk we review various ap-

proaches to achieving full homochirality, focusing mainly on the poly-

condensation of peptides but also addressing the polycondensation of

polynucleotides. In the latter, autocatalysis and enantiomeric cross-

inhibition play key roles1,2, whilst in the former activation and epimer-

ization are crucial3. The latter possibility may have been more relevant

for the prebiotic chemistry on the early Earth, either in the porous

structures in hydrothermal vents or in drying and wetting beach scen-

arios. This scenario may also be more readily amenable to laboratory

investigations. The model captures effects similar to autocatalysis and

enantiomeric cross-inhibition without, however, producing unreactive

‘waste’ product4. Finally, the spreading of chirality on the early Earth

is discussed by solving a set of reaction-diffusion equations based on a

polymerization model. It is found that effective mixing of the early

oceans is necessary to reach the present homochiral5.1 Sandars, P. G. H. (2003). Origins Life Evol. Biosphere 33, 575–587.2 Brandenburg, A. et al. (2005). Origins Life Evol. Biosphere 35,

225–242.3 Plasson, R., Bersini, H. & Commeyras, A. (2004). Proc. Natl Acad.

Sci. 101, 16 733–16 738.4 Brandenburg, A., Lehto, H. & Lehto, K. (2006). Homochirality in an

early peptide world. Astrobiology (submitted), http://arxiv.org/abs/

abs/q-bio/0610051.5 Brandenburg, A. & Multamaki, T. (2004). Int. J. Astrobiol. 3,

209–219.

Photolysis of mixtures of gases containingcyanoacetylene or cyanubutadiyneY. Trolez, J. Jeftic, J.-C. GuilleminSciences Chimiques de Rennes, UMR 6226 CNRS-ENSCR, 35700Rennes, France, e-mail : jean-claude.guillemin@ensc-rennes.fr

Nitriles and particularly unsaturated nitriles play a determining role in

Astrobiology. Cyanoacetylene 1 (H—C———C—C———N) has been observed

in the atmosphere of Titan, in comae, in the Interstellar Medium (IM)

and in numerous lab simulations of Planetary Atmospheres. The first

cyanopolyyne, cyanobutadiyne 2 (H—C———C—C———C—C———N), has

been detected in the IM and in lab simulations of the atmospheres of

Titan and the Primitive Earth. Several approaches leading to mixtures

of products have been reported to detect it and to record its spectra1–3.

We have recently reported the first preparative synthesis of cyano-

butadiyne 24. The photolysis of compounds 1 and 2 could have played a

very important role in the formation of many compounds in the IM, in

comae or planetary atmospheres including the Primitive Earth. The

photolysis of cyanoacetylene by itself or with various other gases has

been reported5,6. Tricyanobenzenes and tetracyanocyclooctatetraenes

have been obtained as well as the corresponding 1,4-adduct or diadduct

with ammonia, phosphine (PH3), silane (SiH4), H2S, alkynes or alkenes.

Performing the same photolysis in gaseous phase with cyanobutadiyne

2 instead of cyanoacetylene 1, we have never been able to detect an

adduct except with thiols. Even if the vapour pressure of cyanobuta-

diyne 2 is low at room temperature, very small quantities of vinylic or

aromatic compounds can be easily detected by 1H NMR spectroscopy.

Similarly, the kinetic instability of cyanobutadiyne, which is much

more important than the one of cyanoacetylene 1, cannot be proposed

as an explanation, cyanobutadiyne being still easily observed in all the

photolyzed samples.1 Alexander, A. J., Kroto, H. W. & Walton, D. R. M. (1976). J. Mol.

Spectrosc. 62, 175–180.2 Haas, S., Winnewisser, G. & Yamada, K. M. T. (1994). Can. J. Phys.

72, 1165–1178.3 Bizzocchi, L., Degli Esposti, C. & Botschwina, P. (2004). J. Mol.

Spectrosc. 225, 145–151.4 Trolez, Y. & Guillemin, J.-C. (2005). Angew. Chem. Int. Ed. 44,

7224–7226.5 Ferris, J. P. & Guillemin, J.-C. (1990). J. Org. Chem. 55, 5601.6 Guillemin, J.-C. et al. (1998). Chem. Eur. J. 4, 1074.

3-Amino-2-propenenitrileJ.-C. GuilleminSciences Chimiques de Rennes, UMR 6226 CNRS-ENSCR, 35700Rennes, France, e-mail : jean-claude.guillemin@ensc-rennes.fr

Cyanoacetylene has been observed in the Interstellar Medium, in co-

mae, in Titan and in many simulations of planetary atmospheres. The

presence of ammonia on the Primitive Earth has been the subject of

strong debates. However, many compounds postulated as precursors or

building blocks (a-aminonitriles, aminoacids etc.) easily give ammonia

on hydrolysis or heating. Cyanoacetylene quickly and easily reacts with

ammonia to form 3-amino-2-propenitrile in very good yields. In the

area of Exobiologie, studies on 3-amino-2-propenitrile have been dra-

matically underinvestigated. We have developed a quite general study

on the chemistry of 3-amino-2-propenenitrile1–3. We demonstrated

particular properties on the chemistry, acidity and basicity in gas phase

of this compound2. On the hypothesis that this compound could be

formed in the IM or planetary atmospheres, we recorded its gas-phase

infrared1 and microwave spectra3 to allow its detection in planetary

atmospheres or in the Interstellar Medium.1 Benidar, A. et al. (2005). J. Phys. Chem. A. 109, 4705–4712.2 Luna, A. et al. (2006). Gas-phase protonation and deprotonation of

cyanovinyl compounds. Chem. Eur. J. (in press).3 Askeland, E. et al. (2006). Microwave spectrum, structure and

quantum chemical studies of a compound of potential astrochemical

and astrobiological interest: Z-3-Amino-2-propenenitrile. J. Phys.

Chem. A. (in press).

Effects of Fe (II) in the formation of biomoleculesin simulations experiments using spark dischargesand aqueous aerosolsM. Ruiz-Bermejo, C. Menor Salvan, S. Veintemillas VerdaguerCentro de Astrobiologıa (CSIC-INTA), Carretera Torrejon-Ajalvir,Km. 4,2, E-28850 Torrejon de Ardoz, Madrid, Spain,e-mail : ruizbm@inta.es

The emergence of life is one of the most puzzling scientific problems. In

this context, it has been proposed that aerosols played a major role on

the origin of life on the Archean Earth. On the other hand, it is postu-

lated that ancient sea had a salinity of 1.5 to 2 times the modern value, a

pH=5–10 and the presence of the banded iron formations show that

dissolved iron was present in excessive quantities in the early Earth.

Our experimental approach to synthesize abiotically organic molecules

with biological interest consist in the simulation of an aqueous aerosol

EANA 2006 Lyon Abstracts80

in a plausible prebiotic atmosphere (CH4, N2 and H2) and in a plausible

ancient sea (pH=5.8, salinity about 2 times the modern sea and Fe+2

0.01 M) and the simulation of storms using spark discharges. Using

different sources of Fe (II) (FeCl2, FeCO3 or FeS) we observed the

formation of some amino acids, hydroxy acids, di- and tri-carboxylic

acids and heterocycles involved in biological process. Indeed, the

presence of dissolved Fe+2 in our simulation experiments generates the

formation of Prussian Blue, Fe4[Fe(CN)6]. This inorganic salt could be

an important reservoir of HCN in the initial prebiotic conditions of

Earth. However, in the experiments carry out in presence of insoluble

FeS the formation of Prussian Blue is not observed but amino acids

containing S are detected.

Chemical effects of gas–water interface: analysisand structural characterization of complex materialsobtained from a CH4/N2/H2 atmosphereand an aqueous aerosolM. Ruiz-Bermejo, C. Menor-Salvan, E. Mateo-Martı, J. AngelMartın-Gago, S. Veintenillas-VerdaguerCentro de Astrobiologıa (CSIC-INTA), Carretera Torrejon-Ajalvir,Km. 4,2. E-28850 Torrejon de Ardoz, Spain, e-mail: ruizbm@inta.es

It has been proposed that aerosols played a major role on the origin of

life on the Archean Earth. Our experimental approach consists of the

simulation of an aerosol in a plausible prebiotic atmosphere and the

simulation of storms using spark discharges. The organic compounds

with biological interest (i.e. amino acids, purine bases) are not present

per se in the raw collected in simulation experiments otherwise as,

generally, unknown precursors. Therefore, it is necessary to character-

ize the structure of these complex materials in order to clarify the

nature of precursors and to find a plausible mechanism of synthesis. We

used different spectroscopic techniques (IR, UV-vis, XPS, Solid State13C NMR spectroscopy) and other analytical tools (HPLC, GC-MS) to

characterize the structure of our products. In our experiment, we ob-

tained one water-soluble fraction (S) and one insoluble fraction (I). The

bulk S fractions are constituted by polar units (containing carboxylic

acids, amines, alcohols, and nitriles) with different molecular weights. It

yields a relatively high amount of amino acids, purines bases and

carboxylic acids. We propose the Strecker synthesis as the most likely

mechanism in the formation of amino acids under our prebiotic con-

ditions. However, the I fraction is an apolar solid that seems to be

formed by large and rigid hydrocarbon chains. The presence of a

punctual unsaturated bond (C——C, C———C) in the chains could be the

reason for the rigidity and the amine and hydroxyl group could allow

the hydrogen bond among neighbour chains. The oxidative cleavage

shows the presence of structures —C——C—C—C——C—.

Studies on prebiotic synthesis and ionophoric activityof model cyclic peptidomimeticsK. Adamala(1,2), R. Ostaszewski(1,3)(1) Institute of Organic Chemistry, Polish Academy of Sciences,Kasprzaka 44/52, 01-224 Warszawa, Poland, e-mail:rysza@icho.edu.pl; (2) Faculty of Chemistry, University of Warsaw,Poland; (3) Faculty of Chemistry, Warsaw University of Technology,Poland

Selective transport of ions and small molecules across cell membranes is

crucial for the origin of the living cell’s homeostasis. Prebiotic synthesis

of simple peptides or peptidomimetics must have been essential for

formation of ion channels and pores in early cell membranes. We report

our attempted synthesis of peptidomimetics with pore-forming activity,

performed under prebiotic-like conditions. Synthesis was based on

compounds already presented in a prebiotic Earth environment. The

key-step of the total synthesis is the Ugi reaction, a four-component

condensation reaction between an isocyanide, an amine, a carboxylic

acid and an aldehyde, leading to the peptidomimetic structures. These

products can be readily cyclized to final ionophoric compound. We

suggest that upon proper substrate choice, intramolecular hydrogen

bonds can be formed between side chains of amino acid used as

substrates for synthesis of peptidomimetic compounds. This hydrogen

bond pattern can be responsible for stereoselective course of Ugi reac-

tion. Ionophoric activity of cyclic compounds is confirmed by the

standard mitochondria swelling assay and by data obtained by

measuring picrate salts trans-phase transport of target compounds.

Oscillating prebiotic model : the theoreticalsubstantiation and the program for experimentalproofV. N. Kompanichenko(1,2)(1) Institute for Complex Analysis, 4 Sholom-Aleyhem Street,Birobidzhan 679016, Russia, e-mail: kompanv@yandex.ru;(2) Department of Chemistry, University of California, 1156 HighStreet, Santa Cruz, CA 95064, USA

Various explored prebiotic models are able to self-complicate under

certain conditions. However, the conducted experiments have not led to

their transformation into a kind of simplest living units. According to

the theoretically elaborated conception1, this transformation is possible

through the intermediate stage – formation of oscillating (pulsing)

prebiotic microsystem. Such a ‘bistate’ system may originate during

non-equilibrium transition of a prebiotic microsystem from the initial

into advanced state, in case there appears the balance between the

states keeping through the oscillations around the highest ‘bifurcate’

point of transition. The system acquires the paradoxical way of or-

ganization – ‘stabilized instability’ : the principally unstable point of

bifurcation is ‘ incorporated’ between two opposite but equal forces.

The regular oscillations to the initial and advanced states give the

transformed microsystem the following properties, which are at the

foundation of life : incessant inner fluctuations and re-arrangement of

molecules; integrity through cooperative events; exchange by matter

and energy with the outside world; forked structure consisting of two

interrelated co-structures; repulsion of the co-structures from the cen-

tral point of instability and their dichotomy at the end of cycle of the

existence, etc. Experimenters are invited to begin experiments in this

way. The aim of the experimental research is to obtain oscillating pre-

biotic microsystems, which are able to evolve to life. During the ex-

periments various prebiotic models should be explored at the state of

bifurcate transition and under oscillating conditions in experimental

chambers.1 Kompanichenko, V. N. (2004). Frontier Perspectives 13(1), 22–40.

Adsorption and thermal transformation of simpleamino acids on oxidesJ.-F. Lambert, L. Stievano, I. Lopes, L. Piao, D. CostaLaboratoire de Reactivite de Surface, UMR 7609, Universite Pierre etMarie Curie, 4 Pl. Jussieu, 75252 Paris Cedex 05, France

It has long been proposed that the surfaces of oxide materials may have

played an important role in promoting and directing the synthesis of

oligopeptides from amino acids, on the prebiotic Earth or in interstellar

conditions. Mostly macroscopic level results have been obtained so far;

the molecular environment of adsorbed amino acids is unknown. In

particular, polymerization selectivities are hard to rationalize, so that

one cannot evaluate the likelihood of the synthesis of ‘useful’ polymers.

In this study, simple amino acids were adsorbed on high surface area

solid oxides (silica, alumina, saponite clay, Al-pillared saponites,

goethite) with well-known surface structures. The adsorbed amounts

were quantified as a function of pH. The adsorbed amino acids were

characterized at the molecular level by vibrational spectroscopy, 13C

NMR and DFT modelling. Thermal activation resulted in the clean

formation of cyclic or linear dimers depending on water activity. Some

hypotheses have to be reconsidered in view of our data. Even in the case

of glycine, no less than four molecular environments are observed for

the deposited amino acid: bulk a- and b-glycine, molecularly adsorbed

zwitterions, and molecularly adsorbed neutral glycine. The systems

studied exhibited a more complicated behaviour than anticipated, and

thus a wider range of opportunity for the appearance of complex

phenomena. Mixtures of two amino acids were also adsorbed on the

EANA 2006 Lyon Abstracts 81

Goldschmidt Conference Abstracts 2007 A653

Generating the aromatic world: Synthesis of aromatic compounds in

icy environments C. MENOR-SALVÁN, M. RUIZ-BERMEJO,

S. OSUNA ESTEBAN AND S. VEINTEMILLAS VERDAGUER Centro de Astrobiología (CSIC-INTA). Ctra. Torrejón-Ajalvir

km. 4.2, Torrejón de Ardoz. E-28850 (Spain); (menorsc@inta.es) The aromatic hydrocarbons are recognized as

astrophysically important molecules and their presece in interstellar ices may contribute to the materials incorporated into planets, satellites, asteroids and comets. Ultimately, PAHs are recognized as key molecules in the study of the origin of life, due to their photochemical properties that could allow to PAHs to play the role of primitive pigment systems that drive synthesis of amphiphilic compounds; assemblies based on aromatic hydrocarbons were proposed as components of informational polymers, containers and mediators in metabolic pathways (1). The disponibility and stability of such aromatic compounds plus their capacity for self-assembly driven by pi-pi stacking interaction and weak forces made the aromatic hydrocarbons good building blocks for protocellular structures. Indeed, it has been demonstrated that amphiphyllic polycyclic aromatic compounds are capable to self-assemble and form bilayer structures (2). We demonstrate that complex mixtures of aromatic compounds could be synthesized in cold systems with water ice and methane as carbon source. Using spark discharges as energy source and generating a “ice reactor” by means of a cycle of freezing-melting we found benzene derivatives as acetophenone, benzaldehyde and benzonitrile and PAHs.

Figure 1: SPME-GC/MS chromatogram showing main aromatic compounds obtained in an icy environment.

References [1] Ehrenfreund P., Rasmussen J., Cleaves J., Chen L. (2006)

Astrobiology 6, 490-520. [2] Chen L., Geiger J., Perlstein J., Whitten D.G. (1999)

J. Phys. Chem. B. 103, 9161-9169.

Dating carbonate rocks with in situ produced cosmogenic 10Be:

Why it often fails S. MERCHEL1, R. BRAUCHER1, L. BENEDETTI1,

O. GRAUBY2 AND D. L. BOURLÈS1 1CEREGE, CNRS UMR 6635, Université Aix-Marseille III,

F-13545 Aix en Provence, France (merchel@cerege.fr) 2CRMCN-CNRS, F-13288 Marseille cedex 9, France

In situ produced cosmogenic nuclides have proved to be valuable tools for environmental and Earth sciences. Progress in the field of accelerator mass spectrometry (AMS) allows the determination of radionuclide concentrations as low as of 104-105 atoms/(g rock) that makes quantifying Earth’s surface processes possible.

However, surface exposure dating of carbonate rocks using the cosmogenic radionuclide 10Be is still problematic. In order to investigate the reasons for this, we have performed extensive step-wise leaching of calcite-rich samples. Results on different grain size fractions clearly indicate the sources of atmospheric 10Be being small clay minerals. We demonstrate that partial-leaching procedures that result in moderate pH levels will not release 10Be (in-situ produced or atmospheric) due to the instant re-absorption on grain surfaces. Under strongly acidic conditions all absorbed atmospheric 10Be is leached from aluminosilicates giving abnormally high 10Be concentrations and consequently exposure ages that are too old (Merchel et al., submitted).

Now, that we understand the main obstacles in analysing 10Be from carbonate rocks, the next steps are clear: We need to concentrate on samples that do not contain clay minerals. This might require working on coarser grain size fractions or recrystallized material. Or we need to find a way to physically and/or chemically separate clay minerals from carbonates before dissolving them. This task is most challenging because clay is generally much more resistant to chemicals than carbonate minerals. After testing several analytical methods, i.e. XRD, IR, TEM-SAED, ICP-OES, SEM-EDX, we are still searching for a “simple and fast” method which could quantify clay concentrations in our samples and could help monitoring the efficiency of future separation procedures.

Acknowledgments: We thank I. Schimmelpfennig,

L. Palumbo and P.H. Blard for their help during field work. D. Borschnek is thanked for performing XRD, H. Miche for ICP-OES, and G. Camoin for optical microscopy at CEREGE. We also acknowledge the good collaboration with J. Huth (MPI for Chemistry, Mainz) in respect to SEM-EDX measurements. The AMS measurements at Gif-sur-Yvette would not be possible without G. Aumaître.

References Merchel S., Braucher R., Benedetti L., Grauby O., and

Bourlés D.L. (2007), submitted to Quaternary Geochronology.

O

Benzaldehyde

N

benzonitrile

O

acetophenone

Naphthalene

biphenyl

1-methyl-naphthalene

2-methylnaphthalene

OO

benzil

O

1-phenyl-1-propanone

O

Benzaldehyde

N

benzonitrile

O

acetophenone

Naphthalene

biphenyl

1-methyl-naphthalene

2-methylnaphthalene

OO

benzil

O

1-phenyl-1-propanone

Ice as matrix for chemical evolution: Synthesis of polycyclic aromatic

hydrocarbons in frozen environment by spark discharges.

C. MENOR-SALVÁN, M. RUIZ-BERMEJO, S. OSUNA ESTEBAN AND S. VEINTEMILLAS VERDAGUER.

Centro de Astrobiología (CSIC-INTA). Ctra. Torrejón-Ajalvir km. 4.2, Torrejón de Ardoz. E-28850 (Spain); menorsc@inta.es

It has been demonstrated that frozen water is a suitable matrix for high order chemistry, such as the oligomerization of nucleotides[1]. In this work we propose that frozen water with realistic temperature variations could be an attractive model in lower order chemistry, boosting the chemical evolution of the organic molecules synthesized by the effect of spark discharges on a suitable prebiotic atmosphere. Our experiment creates a melting-freezing cycle of a liquid water pool under a CH4/N2/H2 atmosphere. After the generation of organic matter by means of spark discharges during 72 h, the system was maintained sealed and the melting-freezing cycle stablished during 3 months. After that, the organic solution in the reactor device was analyzed by solid phase microextraction (SPME) coupled with GC-MS. We found a set of polycyclic aromatic hydrocarbons (PAHs) and other aromatic compounds as acetophenone or benzaldehyde (see figure). PAHs are recognized as key molecules in the study of the origin of life, due to their photochemical properties i.e. as primitive pigment systems that drive synthesis of amphiphilic compounds [2]; with the freezing-melting cycle, we found a stable environment that could be conductive to the synthesis and accumulation of PAHs and prebiotic organic molecules on Mars, Europa, Titan or early Earth.

References [1] Trinks H., Schröder W., Biebricher C.K. (2005) Origins Life Evol. Biosph. 35, 429-445. [2] Segré D., Ben-Eli D., Deamer D.W., Lancet D. (2001) Origins Life Evol. Biosph. 31, 119-145.