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Taxonomia De Invertebrados Fósseis (Oligoceno- Mioceno) Da Ilha Rei George (Antártica Ocidental) E Paleobiogeografia Dos Bivalvia Cenozóicos Da Antártica

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Taxonomia De Invertebrados Fósseis (Oligoceno- Mioceno) Da Ilha Rei George (Antártica Ocidental) E Paleobiogeografia Dos Bivalvia Cenozóicos Da Antártica UNIVERSIDADE DE SÃO PAULO INSTITUTO DE GEOCIÊNCIAS TAXONOMIA DE INVERTEBRADOS FÓSSEIS (OLIGOCENO- MIOCENO) DA ILHA REI GEORGE (ANTÁRTICA OCIDENTAL) E PALEOBIOGEOGRAFIA DOS BIVALVIA CENOZÓICOS DA ANTÁRTICA Fernanda Quaglio Orientador: Prof. Dr. Luiz Eduardo Anelli DISSERTAÇÃO DE MESTRADO Programa de Pós-Graduação em Geologia Sedimentar SÃO PAULO 2007 Polus Antarcticus State IV Hondius 1639 Aos meus pais e irmã, de cujo carinho me alimento para continuar Agradecimentos Sou muito grata às diversas pessoas que acompanharam e contribuíam para meu aprendizado, não apenas durante este Mestrado, mas desde que cheguei ao Instituto de Geociências, em meados de 2003: - Ao meu orientador prof. Dr. Luiz Eduardo Anelli, que me recebeu e acolheu desde o final de minha graduação, oferecendo-me a oportunidade de trabalhar com material antártico; - Ao prof. Dr. Paulo Roberto dos Santos, coordenador do projeto ao qual meu Mestrado se inseriu, pelo apoio financeiro e irrestrito à realização deste Mestrado, pela amizade e por sempre estar disposto a discutir e considerar minhas opiniões; - Ao prof. Dr. Thomas Rich Fairchild, pelas longas conversas sobre ciência e amenidades, pelas sugestões ao longo do desenvolvimento do projeto, e apoio durante minhas fases de desânimo; - À profa. Dra. Wania Duleba, pelas sugestões sempre que precisei, pelos conselhos e conversas, pelas palavras certas nos momentos críticos e por quem nutro grande respeito e amizade; - Ao prof. Dr. Setembrino Petri, pelas bibliografias e discussões, pelo exemplo de inteligência e vontade; - Aos prof. Dr. Paulo César Fonseca Gianinni, André Sawakuchi, Renato Paes de Almeida, Cláudio Riccomini e Oswaldo Siga Jr.; - À grande amiga Larissa Fontes, que me ajudou a seguir em frente quando tudo parecia ter acabado; - À Marisa Monteiro, pela amizade, ajuda e confiança; - Ao Lucas Veríssimo Warren, pela ajuda nas colunas e descrições geológicas, nas interpretações sedimentológicas, pelo apoio e amor ilimitados, por tudo que aprendi; - À colega de sala Paula Andréa Sucerquia Rendón, pela companhia, amizade, sugestões e ajuda; - Aos colegas e amigos Carlos Grohman, Letícia Vicente, Samar Steiner, Luis Fernando Roldan, Liliane Janikian e Andrés Bustamante pela amizade e apoio; - Aos colegas Cléber Pereira Calça, Gabriel Luiz Perez Vieira, Rafael Casati, Rodrigo César Marques e Ricardo Pires Domingues, além de Luiz Fernando Zuleta e Fábio Pinheiro, pela ajuda e sugestões, pelas conversas durante o café e pelas “partidinhas” que amenizavam momentos de tensão; - Ao funcionário Isaac Sayeg, pelo apoio e palavras amigas, e pela força nas atividades de laboratório; - Aos funcionários Sandra, Elaine, Vasco, Flávio, Cláudio e Luiz pelo apoio nas atividades de laboratório e laminação; - Aos funcionários Iolanda, Sônia, Luiz, Maurício e Solange pelo suporte nos trâmites financeiros; - Aos funcionários Ana Paula, Magali, Tadeu e Telma, e às secretárias do GSA Soninha e Graça; - Às funcionárias da biblioteca Érika, Brenda, Aline, Luciana, Maria e Sandra, pelas ajuda com os comuts e outras referências; - Aos funcionários da informática Pedro e Erickson, pelo socorro em momentos de urgência; - Aos funcionários Jaime, João, Marquinho, Manoel, Elias, Paulo e Celina. Agradeço também à CAPES pelo suporte financeiro na forma de bolsa e ao CNPq/PROANTAR pelo apoio financeiro na realização das análises e viagens. Agradeço especialmente aos meus pais, Aureliano e Nivea, pela confiança, pelo esforço e pelo exemplo de educação e família, e à minha irmã e grande amiga, Cibelle, a quem sempre admirei e quem me ensinou a ser crítica e obstinada. “… the history of science can make your work seem more worthwhile to you. As a scientist, youʹre probably not going to get rich. Your friends and relatives probably wonʹt understand what youʹre doing. But you can get great satisfaction by recognizing that your work in science is a part of history.” Steven Weinberg Resumo As pesquisas apresentadas nesta dissertação integram o projeto CNPq – PROANTAR 550352/02-3 “Mudanças paleoclimáticas na Antártica durante o Cenozóico: o registro geológico terrestre”, que estuda os depósitos cenozóicos da ilha Rei George em busca elucidação do histórico ambiental e climático desta região antártica. A evolução dos padrões de circulação marinha e atmosférica no Hemisfério Sul ocorreu em resposta ao isolamento geográfico e térmico da Antártica, resultado de sua separação da Austrália, no limite Eoceno/Oligoceno, e da América do Sul, no final do Oligoceno. Sob este aspecto, o estudo de organismos fósseis registrados nos depósitos cenozóicos da Antártica contribui para o entendimento das evoluções biológicas e ambientais ocorridas concomitantemente às mudanças paleogeográficas, oceanográficas e climáticas na região ao longo do Cenozóico. Frente à dificuldade de acesso, demanda logística e extensa cobertura de gelo, apenas uma pequena porção do registro geológico da Antártica está acessível para pesquisa. Afloramentos da ilha Rei George registram as mudanças climáticas e ambientais ocorridas do Oligoceno ao Mioceno, incluindo evidências do primeiro evento de glaciação perene no oeste do continente (Oligoceno). A despeito da abundância de fósseis nos estratos cenozóicos da ilha, são poucos os trabalhos taxonômicos com descrição sistemática detalhada de bivalves fósseis. O primeiro módulo do presente estudo apresenta a descrição taxonômica de invertebrados de depósitos cenozóicos aflorantes em duas localidades da ilha Rei George, Antártica ocidental. Da Formação Cape Melville (Mioceno), península Melville, foram descritos sete táxons de bivalves, incluindo seis espécies novas. Da Formação Polonez Cove (Oligoceno), Pico Vauréal, uma região previamente inexplorada paleontologicamente, foram descritos sete táxons de invertebrados (bivalves, braquiópodes, tubos de serpulídeos, briozoários e fragmentos de equinodermes), incluindo duas espécies novas. O segundo módulo corresponde à reunião dos gêneros de bivalves registrados em depósitos cenozóicos da Antártica. A análise do registro apontou para o conhecimento bastante incipiente sobre a diversidade de bivalves antárticos ao longo do Cenozóico. Além disso, a comparação entre gêneros de bivalves cenozóicos registrados na Antártica e Nova Zelândia revelou que a maior parte dos gêneros compartilhados está registrada em depósitos eocênicos, o que suporta o isolamento geográfico da Antártica e a redução do intercâmbio faunístico entre a Antártica e regiões periféricas após o Oligoceno. A análise do registro sugeriu um evento de dispersão intenso durante o Eoceno, e pequenos pulsos de dispersão após o Oligoceno. O padrão de distribuição dos táxons concorda parcialmente com as reconstituições de paleocorrentes disponíveis na literatura. A dispersão durante o Eoceno teria ocorrido da Antártica para a Nova Zelândia na direção do Atlântico para o Pacífico. Este evento de dispersão concorda com a hipótese de existência de conexões marinhas de plataforma rasa entre o oeste e o leste da Antártica (“Passagem de Shackleton”) e da província Weddeliana do final do Cretáceo ao Eoceno. Os eventos de dispersão pós- oligocênicos teriam ocorrido durante e após o estabelecimento da Corrente Circum-Antártica, não mais pela “Passagem de Shackleton”, mas margeando a Antártica pelas bordas ocidental atlântica e oriental em direção à Nova Zelândia. A análise do registro dos bivalves cenozóicos da Antártica também concorda com a hipótese de glaciação perene a partir do início do Oligoceno na região leste do continente, e na metade do Oligoceno na região oeste, com temperaturas mais amenas que as observadas atualmente. Abstract The research presented in this dissertation comprised part of the CNPq – PROANTAR Project 550352/02-3 “Mudanças paleoclimáticas na Antártica durante o Cenozóico: o registro geológico terrestre”, which studies Cenozoic deposits from King George Island in order to elucidate the environmental and climatic Cenozoic histories of this Antarctic region. Cenozoic evolution of marine and atmospheric circulation in the Southern Hemisphere occurred in response to the geographic and thermal isolation of Antarctica, which resulted from the separation of Antarctica from Australia, around Eocene/Oligocene boundary, and from South America, during the late Oligocene. Thus, study of fossil organisms from Antarctic Cenozoic deposits contributes to the understanding of biological and environmental evolutions that accompanied paleogeographic, oceanographic and climatic changes during the Cenozoic. As a result of the difficult access, logistic demand and extensive ice cover, only a small part of the Cenozoic Antarctic record is available for study. King George Island records climatic and environmental changes from the Oligocene to the Miocene, including evidence of the first full-scale glaciation (Oligocene) of West Antarctica. Despite the abundance of fossils in Cenozoic deposits of the island, taxonomic studies with detailed systematic descriptions of bivalves are very rare. The first section of this work consists of taxonomic descriptions of invertebrates from Cenozoic deposits cropping out in two localities of King George Island, West Antarctica. Seven taxa of bivalves, including six new species were described from the Cape Melville Formation (Miocene), at Melville Peninsula. Seven taxa of invertebrates (bivalves, brachiopods, serpulid tubes, bryozoans, and echinoderm fragments) were described from the Polonez Cove Formation (Oligocene), at Vauréal Peak, a site previously unexplored paleontologically. The second section
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