Upper Pleistocene–Holocene in the continental slope of the Cará Basin: an integrated analysis based on planktic foraminifera, sedimentological and geochemical aspects

Autor:	Robbyson Mendes Melo, Eldemar de Albuquerque Menor, George Satander Sá Freire, Agathe Arrissa Noucoucouk
Rok vydání:	2021
Předmět:	geography geography.geographical_feature_category biology Pleistocene Continental shelf Paleontology Biozone Biostratigraphy biology.organism_classification Foraminifera Oceanic basin Quaternary Geomorphology Geology Holocene
Zdroj:	Revista Brasileira de Paleontologia. 24:179-194
ISSN:	2236-1715 1519-7530
DOI:	10.4072/rbp.2021.3.02
Popis:	This research addresses paleoclimatic variations using sedimentological, geochemical, and planktic foraminifera. The study was carried out in a survey core (ANP 1011) collected on the continental slope of the Icarai Sub-basin (Ceara Basin), on the coast of the Municipality of Itapipoca, CE, Brazil. Particle size analysis, CaCO3 content, Ti/Ca and Fe/Ca ratios, and the analysis of foraminifera associations for biostratigraphic purposes were performed. Based on the relative abundance of planktic foraminifera, with indicators of warm and cold water throughout the studied cores, two biozones (Y: Upper Pleistocene and Z: Holocene), and two subzones (Z2 and Z1) were recognized. The data of sedimentological markers obtained confirmed the occurrence of more wet phases in northeastern Brazil during the early stages of the Holocene. The Ti/Ca and Fe/Ca ratios, as well as the geochemical and micropaleontological proxies, indicated a farther north displacement of the Intertropical Convergence Zone (ITCZ) in the Pleistocene–Holocene transition. This may have caused greater precipitation in the Northeastern region of Brazil, effectuating the entry of a high volume of terrestrial sediments directly into the ocean basin. Keywords: Quaternary biostratigraphy, marine sedimentation, ITCZ mobility, paleoclimate. RESUMO – Esta pesquisa aborda as variacoes paleoclimaticas, utilizando foraminiferos planctonicos, marcadores sedimentologicos e geoquimicos. O estudo foi realizado em um testemunho de sondagem (ANP 1011) coletado no talude continental da Sub-bacia Icarai (Bacia do Ceara), costa do Municipio de Itapipoca, CE. Foram realizadas analises granulometricas, teor de CaCO3, razoes Ti/Ca e Fe/Ca e estudo das associacoes dos foraminiferos para fins bioestratigraficos. Com base nas abundâncias relativas de foraminiferos planctonicos indicadores de aguas quentes e frias ao longo dos testemunhos estudados, foram reconhecidas duas biozonas (Y: Pleistoceno superior e Z: Holoceno) eduas subzonas (Z2 e Z1). Os dados de marcadores sedimentologicos obtidos confirmam a ocorrencia de mais fases umidas no Nordeste do Brasil durante o inicio do Holoceno. As razoes dos elementos Ti/Ca, Fe/Ca, indicam, como os proxies geoquimicos e micropaleontologicos, um deslocamento mais ao norte da Zona de Convergencia Intertropical (ZCIT) na transicao Pleistoceno-Holoceno, provocando maior precipitacao na regiao nordestino do Brasil com entrada de um volume alto de sedimentos terrigenos diretamente para a bacia oceânica. Palavras-chave: bioestratigrafia do Quaternario, sedimentacao marinha, mobilidade da ZCIT, paleoclima.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::a49ac62d35e5374ecae25499dcd28f36 https://doi.org/10.4072/rbp.2021.3.02 Zobrazit plný text záznamu