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ISBN 978-85-7193-184-8 – Editora Interciência 2007 Paleontologia: Cenários de Vida
FIRST RECORD OF FOSSILS LEAVES FROM THE KELLER PENINSULA,
KING GEORGE ISLAND, ANTARCTICA
Alexander Wilhelm Armin Kellner1,2, Tânia Lindner Dutra3, Marcelo de Araújo Carvalho1, Renato Rodriguez
Cabral Ramos1, Orlando N. Grillo1,2, Helder de Paula Silva1,4, Douglas Riff 5 & Pedro Seyferth R. Romano1,2
1Departamento de Geologia e Paleontologia, Museu Nacional, Universidade Federal do Rio de Janeiro,
Quinta da Boa Vista s/n, São Cristóvão, 20940-040, Rio de Janeiro, RJ, Brasil
2Bolsista CNPq; 3Programa de Pós-graduação em Geologia, Universidade do Vale dos Sinos, Avenida
Unisinos, 900, 93022-000, São Leopoldo, RS, Brasil
4Ins tuto de Biociências, Ciências Biológicas, Universidade do Grande Rio Professor José de Souza Herdy,
Rua Professor José de Souza Herdy, 1160, 25071-200, Duque de Caxias, RJ, Brasil
5Universidade Estadual do Sudoeste da Bahia, Departamento de Ciências Naturais, Estrada do Bem Querer,
Km 04, 45083-900, Vitória da Conquista, BA, Brasil
E-mail: kellner@mn.ufrj.br, tdutra@unisinos.br, mcarvalho@mn.ufrj.br, rramos@mn.ufrj.br,
ongrillo@gmail.com, helder@acd.ufrj.br, driff 2@mn.ufrj.br, psrromano@gmail.com
RESUMO
Na expedição da 25ª Operação Antártica (OPERANTAR XXV) à Península Antártica, os
primeiros restos de folhas fósseis foram identifi cados para a Península Keller, Ilha King George.
O material está preservado como impressões em um tufo avermelhado do Membro Tyrrel
Ridge, Formação Visca Anchorage. Três morfótipos foram identifi cados, indicando a presença
de Nothofagus (Nothofagaceae), de um tipo relacionado a Monimiaceae (Magnoliopsida),
similar a Monimiophyllum antarcticum, e de uma possível Magnoliidae (Lauraceaea?). Junto
com outros elementos já identifi cados para a ilha, esta tafofl ora sugere uma idade Paleoceno
Superior? - Eoceno Inferior para a deposição.
Palavras-chave: Folhas fósseis, Península Antártica, Paleogeno
ABSTRACT
During the expedition of the 25th Antarctic Operation (OPERANTAR XXV) to the Antarctic
Peninsula, the fi rst fossil leaves specimens were identifi ed from the Keller Peninsula, King
George Island. The specimens are preserved as impressions in a reddish tuff from the Tyrrel
Ridge Member, Visca Anchorage Formation. Three morphotypes were identifi ed, representing
the presence of Nothofagus (Nothofagaceae), a type related to Monimiaceae (Magnoliopsida),
similar to Monimiophyllum antarcticum, and a possible Magnoliidae (Lauraceaea?). Together
with other elements previously identifi ed for the island, this taphofl ora suggests an Upper
Paleocene? - Lower Eocene age for those deposits.
Key-words: Fossil leaves, Antarctic Peninsula, Paleogene
628 Paleontologia: Cenários de Vida
1. INTRODUCTION
From the paleontological point of view, Antarctica can be regarded as practically unknown. There
are comparatively few studies regarding fossils from this continent, which is due to the diffi culties
in organizing expeditions to this region where extreme climatic conditions predominate and the rock
exposures, essential for paleontological activity, are restricted. Despite that, there have been advances in
the last decades, with several countries supporting projects aiming the search for Antarctic fossils.
Among those is the PROANTAR (Brazilian Antarctic Program) from the CNPq (Conselho Nacional
de Desenvolvimento Científi co e Tecnológico) that has funded fi eld activities to collect fossils in the
past (e.g., Dutra, 2001; Anelli et al., 2006). In 2006 PROANTAR approved the project PALEOANTAR
(Antarctic Paleontology, coordinated by the Museu Nacional/UFRJ), which fi rst phase consisted in
prospecting the James Ross Island at the Antarctic Peninsula for macro-and microfossils during the
Antarctic summer of 2007 (during the twentieth fi fth Antarctic Operation, OPERANTAR XXV).
On the way back, the members of the PALEOANTAR had the opportunity to explore the outcrops
around the Admiralty Bay, particularly at the Keller Peninsula, what was done on February 7th and
March 1st. This effort resulted in the collecting of several samples of petrifi ed wood and fossil leaves.
Due to the rarity of the fossil leaves, the fi rst ones from the Keller Peninsula, a short account of this
occurrence is provided here.
Fig. 1: Map of the King George Island indica ng the locality of the Keller Peninsula and the Estação Antár ca Comandante Ferraz
(EACF).
Alexander Kellner, Tânia Dutra, Marcelo Carvalho, Renato Ramos, Orlando Grillo, Helder Silva, Douglas Riff & Pedro Romano 629
2. GEOLOGICAL SETTING
The geology of the King George Island (the more northern of the South Shetland Islands), located
between the Drake Passage and the Brainsfi eld Strait, is quite complex (Birkenmajer, 1980; 2001).
This is particularly true for the Keller Peninsula at the Admirality Bay where the fossil leaves described
in this paper were found.
The material was collected between Mount Flagstaff (“Morro da Cruz”) and Mount Birkenmayer
(“Pico Norte”), close to the ridge uniting those hills (GPS: S 62°04’31.7”; W 058°24’14.9”) (Figure
1-2). Several samples of petrifi ed wood, most showing carbonization, were collected bellow this
ridge, particularly at two points (GPS: S 62°04’32.1”; W 058°24’36.8” and S 62°04’28.9”; W
058°24’16.8”).
According to Birkenmajer et al. (1983) the rocks that outcrop in this area belong to the Visca
Anchorage Formation of the Martel Inlet Group. This unit is subdivided into the Barton Buttress
Member and Tyrrel Ridge Member. The Barton Buttress Member, situated at the base, is about
110 m thick. This unit is formed essentially by light colored (grey and greenish) andesite and lava
fl ows with varying thickness. Intercalated with those are tuffs and volcanic breccia, whose colors
vary from red and purple to yellow (Birkenmajer et al., 1983). Those rocks are overlain by the
Tyrel Ridge Member whose thickness varies around 30 meters. It consists of coarse agglomerates
composed by andesite fragments and thin layers of purple to yellow tuffs. Both members were
not mapped in detail. It has been pointed out that the Tyrel Ridge Member shows the presence of
petrifi ed wood (Birkenmajer et al., 1985).
Fig. 2: Photograph of the Keller Peninsula indica ng the approximate loca on where the material was collected (short arrow), between
Mount Flagstaff and Mount Birkenmayer, near the Brazilian Sta on (Estação Antár ca) Comandante Ferraz (EACF).
The fossil leaves described here were preserved in a comparatively dense reddish rock. Two
petrographic sections were made of one of the specimens. They show that the matrix is made by iron
oxides and hydroxides that comprise about 80% of the thin section. Calcite grains are found dispersed
630 Paleontologia: Cenários de Vida
in the matrix, possibly representing former vitroclasts. Some show the presence of millimetric shards
and spherulites which were formed by devitrifi cation. Despite the fact that the intense formation
of iron has masked most of the matrix of this rock, the features presented above suggest that the
specimen represents a tuff that was diagenetically modifi ed.
Based on the information above, we conclude that the fossil leaves described here come from the
Tyrrel Ridge Member.
3. DESCRIPTION
Two tuff samples with fossil leaves were found, all housed at the paleobotanical collections of the
Museu Nacional/UFRJ under the numbers 451 Pbe to 453 Pbe (Figures 3-6). The larger one was
further divided into two pieces (451 Pbe; 452 Pbe) in order to expose more leaves. In one a small
piece for thin sections was taken.
Fig. 3: In 1, the largest tuff sample (451 Pbe), whit several leaf impressions preserved. In 2, detail showing the leaf tenta vely a ributed
to Monimiaceae (? Monimiophyllum antarc cum) and, in 3, detail of Nothofagus leaf showing the closed secondary vena on. Scale
bar: 20 mm.
Alexander Kellner, Tânia Dutra, Marcelo Carvalho, Renato Ramos, Orlando Grillo, Helder Silva, Douglas Riff & Pedro Romano 631
Fig. 4: In 1, impression of a leaf a ributed to the genus Nothofagus. Scale
bar: 20 mm; In 2, a detailed view showing the great number of craspedo-
dromic secondaries. Scale bar: 10 mm.
Overall the leaves are not well preserved. More than ten
fragments could be identifi ed but this number is likely
higher, with several possible still inside the matrix. All
are incomplete and preserved as impressions.
Three morphotypes can be distinguished. The most
common shows typical architectural characters of the
genus Nothofagus Blume (Nothofagaceae), with the
primary vein, the secondaries and part of the third order
venation preserved (Figures 3.3; 4.1, 4.2). Those features,
mainly the close disposition of the secondaries and their
plicate character, have been found in leaves attributed
to Nothofagus subferruginea (Dúsen) Tanai (see Tanai,
1986: plate 9:7) and after reclassifi ed by Dutra & Batten
(2000) like Nothofagus hillii. Between the modern
representatives of this genus such morphologic features
are found in Nothofagus alessandri Espinosa, a deciduous
that nowadays lives under seasonal climates in Chile,
between 30-35°S. Since the leaf margins are not well
preserved we cannot confi rm these affi nities.
Another incomplete leave shows affi nities with Nothofagus but differs from the former by having
weaker folds on the lamina and more spaced secondaries (Figure 5). Those features, associated
with the apparently more ovate shape of this material suggest that this specimen could be related
to Nothofagus glauca (Phil.) Krasser, another element of extant Chilean and Argentine vegetation,
found in high areas of the Coastal and Andean Cordillera.
A second morphotype comprises an elongated and coriaceous leave where only the main venation is
apparent (Figure 3.2). The external surface is smooth with the leaf margins showing a conspicuous
sinuosity that probably refl ects its original serrate and wavy nature. Despite the poor preservation,
this specimen probably represents a taxa closely related to Monimiophyllum antarcticum Zastawniak,
described in Birkenmajer & Zastawniak (1989). This species was included in the Monimiaceae
(Magnoliopsida) and together with Nothofagus, is the most common morphotype of this
paleoassemblage, each one represented by 3 or 4 leaf remains. Exclusive of the Southern Hemisphere,
the modern representatives of this group lives in tropical to subtropical and wet climates and their
origin can be traced to the Cretaceous of Antarctica.
632 Paleontologia: Cenários de Vida
Fig. 5: Tuff sample 452 Pbe, showing Nothofagus sp. In 1, general view of the material. Scale bar: 20 mm. In 2, a detailed view. Scale
bar: 10 mm.
The third morphotype (Figure 6) is represented by a laurophyllous leaf, with curved upward secondaries,
suggesting a brochidodromous pattern, common in the Magnoliidae (Lauraceaea?). This venation
pattern is very common in the King George taphofl oras, mainly in those of Upper Paleocene?-Lower
Eocene deposits (Birkenmajer & Zastawniak, 1989; Dutra, 2004). Based on this specimen it is likely
that the climate in this region when this fl ora was established was not very cold or dry, at least during
part of the year.
Fig. 6: Tuff sample (453 Pbe) containing a laurophyllous impression with upward secondaries. In 1, whole sample (Scale bar: 20 mm)
and, in 2, detail of the leaf (Scale bar: 10 mm).
Alexander Kellner, Tânia Dutra, Marcelo Carvalho, Renato Ramos, Orlando Grillo, Helder Silva, Douglas Riff & Pedro Romano 633
4. DISCUSSION AND CONCLUSIONS
Despite the incomplete and fragmentary nature of the leaves reported here, this material provides
some new information for the study of the taphofl oras of the King George Island. Nothofagus is
presently known by over 30 extant species that are restricted to the Southern Hemisphere, namely
in New Zealand, Australia, New Guinea, New Caledonia, and South America (Gandolfo & Romero,
1992). Their phylogeny can be regarded as well researched (Jordan & Hill, 1999) and agrees with
their macrofossil record (Cook & Crisp, 2005). The fossil species attributed to this genus is also in
the range of 30, but according to Jordan & Hill (1999) only seven are based on specimens that show
well preserved of both cuticular and leaf architectural characters.
The general pattern observed in the specimens from the Tyrrel Ridge Member of the Visca Anchorage
Formation clearly suggests the presence of the genus Nothofagus, which has been reported elsewhere
in the Antarctic Peninsula. The leaves show affi nities with the modern forms Nothofagus alessandri
and Nothofagus glauca, and with fossil material described from other areas of the King George Island,
Nelson, Seymour and James Ross islands, like Nothofagus subferruginea and Nothofagus hillii Island
(Birkenmajer & Zastawniak, 1989; Dutra & Batten, 2000; Dutra, 2001; 2004).
Ages for fossil leaves of Nothofagus vary from the Upper Cretaceous to the Late Pleistocene. Based
on the pollen record, the oldest records of this genus come from Antarctica (Baldoni, 1987; Dettman
et al., 1990) and South America (Baldoni & Askin, 1993). New molecular data suggests that the
modern forms diversifi ed only during the Paleogene (Cook & Crisp, 2005).
The occurrence of taxa similar to modern species of Nothofagus can be regarded as indicative of warm
temperate (subtropical) to temperate climate, supporting the general idea that this kind of climate was
present form the late Cretaceous until the beginning of the Middle Eocene in the areas of the northern
Antarctic Peninsula (e.g., Dutra, 2004).
From the taphonomic point of view, leaves are comparatively fragile and their transportation tends
to be reduced. Therefore we propose that the Tyrrel Ridge Member and perhaps the whole Visca
Anchorage Formation was deposited in a sub aerial context and that the volcanic activity nearby
was the main cause of vegetation recovering and has made the preservation of leaves possible. The
remains of fossil leaves showing features of Nothofagus, mainly those mesophyllic and signals of
deciduousness, associated with probable Monimiaceae and Lauraceae are found also in the Fossil
Hill Flora from Fildes Peninsula (Fossil Hill Formation, Fildes Peninsula Group) in the King George
Island (Zastawniak & Birkenmajer, 1989). Therefore the specimens reported here suggests correlation
between those stratigraphic units present in the central and southern part of the Island and a Upper
Paleocene ? - Lower Eocene age for those deposits as suggested by Dutra (2004).
5. ACKNOWLEDGMENTS
We would like to thank Dennis T. de Jesus and André Schumann Rosso (SECIRM - Secretaria da
Comissão Interministerial para os Recursos do Mar) for allowing our work at the Admiralty Bay.
Francisco E. S. Petrone and Roberto do Val Vilela, both from the Clube Alpino Paulista (CAP),
are thanked for their help during the fi eld activities of the PALEOANTAR project. We also thank
Captain José Carlos Parente and the crew of the oceanographic ship Ary Rongel (NApOc) for all their
assistance during the fi eld activity of this project.
634 Paleontologia: Cenários de Vida
Funding for the PALEOANTAR project was provided by the Conselho Nacional de Desenvolvimento
Científi co e Tecnológico (CNPq 304785/2003-2 and PROANTAR 55.7347/2005-0) and the Fundação
Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ - E-26/152.885/2006),
grants to A.W.A.K. T.L.D acknowledges the support of the CNPq to her studies of the Antarctic fl ora
(PROANTAR 55.7357/2005-0).
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