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RESTOS VEGETALES PERMINERALIZADOS: UNA NUEVA VENTANA A LA

VEGETACIN PASADO DE PATAGONIA Y ANTRTICA

(Permineralized plant debris: A novel window to the past vegetation of

Patagonia and Antarctica)

Nishida, H.

1,2

, Uemura, K.

3

, Terada, K.

4

, Yabe, A.

3

, Asakawa, T.

5

, Yamada, T.

6

, Kurita,Y.7, Rancusi, M.

8, Hinojosa, L.F.

9, and M. Leppe

10

1Department of Biological Sciences, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo, 112-8551 Japan. E-

mail: helecho@bio.chuo-u.ac.jp2Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan3National Museum of Nature and Science, Tokyo, 169-0073 Japan4Fukui Prefectural Dinosaur Museum, Fukui, 911-8601 Japan5Faculty of Science, Chiba University, Chiba, 263-8522 Japan6Faculty of Science, Kanazawa University, Kanazawa, Japan 920-11927Faculty of Science, Niigata University, Niigata, 950-2181 Japan8Colegio Compaia de Maria, Santiago, Chile9ChileFacultad de Ciencias, Universidad de Chile, Santiago, Chile

10

Instituto Antrtico Chileno-INACH, Punta Arenas

Permineralized plant fossil assemblages that are preserved in certain terrestrial or shallow

marine deposits are rich source of not only plants but also of other co-existed biota or evenecosystems of the past. Two major preservation types have historically provided biological

information of remarkable quality and quantity. Calcareous concretions represented, for

example, by Carboniferous coal-balls and Cretaceous Hokkaido nodules from Japan are theone, and the silicified peat layer such as the famous Devonian Rhynie Chert, Permian

Homevale Chert of Australia, and Eocene Princton Chert of Canada are the other. All these

fossil types provide novel aspects of past vegetation and environment in contrast to those

based on fossils of other preservation types. In Patagonia or even in South America, suchmaterials have not been found or studied much, excepting larger and more attractive fossils

such as wood.

This work summarizes recent results obtained from our field research in south Chile and inAntarctica, which is aimed to collect permineralized plant remains, particularly focusing on

small debri preserved in calcareous concretions of shallow marine origin or in silicified

peat of terrestrial origin.

The first plant-containing calcareous concretion from Patagonia was found at Riesco Islandin 2003. Various array of terrestrial plants and fungi have been identified within acetate-

cellulose peel sections obtained from only three nodules possibly derived from the

Paleocene Chorillo Chico Formation (Nishida et al., 2006). Most interestingly the

assemblage consists of a large amount of tiny plant debris including epiphytic fungi,mosses, and epiphytic filmy fern, which are not expected to be preserved in usual

depositional condition (Fig. 1). Similar concretions have been collected from Riesco Island

and other localities in Magallanes region in our later field investigation. A certain amountof nodules are confirmed to have originated from the Late Cretaceous Dorotea Formation

based on associated ammonites.

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Fig. 1. A-O. Plantas permineralizadas de la Formacin Chorrillo Chico. A. Cormo de Bryophyta. L1, L2:apndices foliares. B,C. Conidioma de Coelomyceta que contiene una conidiospora (flecha). D. Esporangio

deLophosoria. Puntas de flecha indican borde marginal tpico al gnero. E. Rizoma de Hymenophyllacea. F.

Rizoma de Trichomanes radicans Sw., especies actuales para la comparacin. G, H. Retoo y hoja de

Cupressacea. I, Retoo de Podocarpacea y la hoja tipo-1. J. Hoja tipo-2 de Podocarpacea. K, Posible retoo

ovulifero de Pteridosperma. L. Semilla del K ampliada. M-O. Fruta angiosprmica en forma de estrella. M, N.

Imgenes por TC. O. Seccin delgada. Escalas: A, D, 100 m. B, G-K, M, 1 mm. E, F, 0,5 mm.

Fig. 1. A-O. Permineralized plants from the Chorrillo Chico Formation. A. Bryophyta cormus. L1, L2: leafy

appendages. B,C. Coelomycetes conidioma containing a conidiospore (arrow). D. Sporangium of Lophosoria.

Arrowheads indicate typical spore marginal rim. E. Hymenophyllaceae rhizome. F. Rhizome of extant

Trichomanes radicansSw. for comparison. G, H. Cupressoid shoot and leaf. I, Podocarpaceous shoot and leaf

type-1. J. Podocarpaceous lear type-2. K,L. Possible Pteridosperm ovuliferous shoot. M-O. Star-shaped

angiosperm fruit. M,N. CT images. O. Thin section. Scales: A, D, 100 m. B, G-K, M, 1 mm. E,F, 0.5 mm.

Attempts to find similar calcareous concretions of the same time-span in northern part of

Chile became successful at Cocholgue, north of Tom, Concepcin Province. Well-

preserved plant debri have been found from the Maastrichtian Quiriquina Formation, alsoyielding petrified wood. It has been identified by now a wood rotting fungus, an epiphytic

lycopod strobilus; fern rhizomes and rachises, including those of dennstaedtiaceous ferns;

various conifer wood and leaves; and angiosperm remains (Fig.2, A-I). The assemblageshows components of humid warm temperate mixed forest that do not exist in Chile now.

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In 2011, a silicified peat layer was found for the first time in South America at Cocholgue

(Fig. 2, J-L).

Fig. 2. A-I. Plantas permineralizadas de la Formacin Quiriquina. A-C. Estrbilo de LycopodiumSeccin

Huperzia. D. Conidioma de hongo destruyendo la madera. E,F. Rizoma y raquis del helecho

Dennstaedtioideo. G, H. Retoo y hoja de cuprescea. I. Retoo de Araucaria. J, K. Turba silicificada de la

Formacin Navidad. L. Rizoma de gleichenicea. M. Vegetacin actual pantanosa de la isla de Chilo

mostrando Gleicheniay el bosque valdiviano detrs. Escalas 1 mm.

Fig. 2. A-I. Permineralized plants from the Quiriquina Formation. A-C. Strobilus of Lycopodium Section

Huperzia. D. Conidioma of wood rotting fungus. E,F. Dennstaedtioid fern rhizome and rachis. G, H.Cupressoid conifer shoot and leaf. I. Araucaria shoot. J, K. Silicified peat from the Navidad Formation. L.

Gleicheniaceous rhizome. M. Present bog vegetation in Chiloe Island showing Gleichenia and Valdivian

forest behind. Scales 1 mm.

H.N. and M.L. tried to find comparable concretions in Antarctica in 2011. Because of bad

weather, only one nodule containing a piece of wood was available, leaving future

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possibility. The permineralized debri assemblage can successively provide anatomy-based

rich paleobiological information.

ACKNOWLEDGEMENTSThis work is supported by the Grant-in-Aid for Scientific Survey nos. 18405013, 21405012

and 24570112 from MEXT Japan to HN, and has been realized with the courtesy ofConsejo de Monumentos Nacionales de Chile. Instituto Antartico Chileno (INACH)logistically supported the field work in Antarctica.

REFERENCESNishida, H., Uemura, K., Terada, K., Yamada, T., Rancusi, M. H., and Hinojosa, LF. 2006.

Preliminary report on permineralized plant remains possibly from the Paleocene Chorrillo

Chico Formation, Magallanes Region, Chile. In: Nishida, H. (ed.) Post-Cretaceous Floristic

Changes in Southern Patagonia, Chile. Chuo University, Tokyo, pp. 11-27.