Integrated calcareous nannofossil and magnetostratigraphic record of ODP Site 709: Middle Eocene to late Oligocene paleoclimate and paleoceanography of the Equatorial Indian Ocean

Autor(es)

Villa, Giuliana ^[1] ; Florindo, Fabio ^{[2, 3]} ; Persico, Davide ^[1] ; Lurcock, Pontus ^[3] ; de Martini, Ana Paula ^[2] ; Jovane, Luigi ^[2] ; Fioroni, Chiara ^[4]

Afiliação do(s) autor(es)

^[1] Univ Parma, Dipartimento Sci Chim Vita & Sostenibilita Ambien, Parco Area Sci 157 A, I-43124 Parma - Italy

^[2] Univ Sao Paulo, Inst Oceanog, Praca Oceanog 191, BR-05508120 Sao Paulo - Brazil

^[3] Ist Nazl Geofis & Vulcanol, Via Vigna Murata 605, I-00143 Rome - Italy

^[4] Univ Modena & Reggio Emilia, Dipartimento Sci Chim & Geol, Via Campi 103, I-41125 Modena - Italy

• Tipo de documento: Artigo Científico
• Fonte: MARINE MICROPALEONTOLOGY; v. 169, DEC 2021.
• Citações Web of Science: 0

Resumo

We investigated the calcareous nannofossil biostratigraphy and magnetostratigraphy of middle Eocene - lower Oligocene sediments from ODP Hole 709 C, equatorial Indian Ocean. The new bio-magnetostratigraphic analyses have resulted in an accurate biochronology of the interval spanning Chrons C20r (middle Eocene) to C12r, in which 29 bioevents were investigated, in a 12 myr interval. The magnetostratigraphic signal is less clear across the Eocene-Oligocene transition (EOT) but becomes more reliable at the top of Chron C13n to Chron C12r (early Oligocene). Quantitative analyses of calcareous nannofossil assemblages allowed recognition of the Middle Eocene Climatic Optimum (MECO) and the long cooling trend leading to the glacial state starting in the early Oligocene. We identify two hiatuses, in the lower middle Eocene and across the Eocene-Oligocene Transition (EOT). Across the latter unconformity, a major transition from oligotrophic to eutrophic favoring nannofossil taxa highlights the enhanced sea surface nutrient availability during the transition to the early Oligocene glacial system. Finally, a late Oligocene warming event is recorded at this site by the increase in calcareous nannofossil taxa that preferred warm water. (AU)

• Processo FAPESP: 16/24946-9 - Mudanças do nível do mar e o Sistema Monçônico Global: avaliação através de testemunhos marinhos no Brasil
• Beneficiário: Luigi Jovane
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático