Artículo
Eocene paleoceanographic and paleoclimatic events recognized by assemblages of dinoflagellate cysts in the Southwest Atlantic Ocean
Fecha de publicación:
10/2023
Editorial:
Pergamon-Elsevier Science Ltd
Revista:
Journal of South American Earth Sciences
ISSN:
0895-9811
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Variations in the relative frequencies between cosmopolitan dinoflagellate cysts and Antarctic assemblage species indicate temperature changes and variations of ocean currents during the Paleogene. This study is based on the analysis of 23 samples from two stratigraphic intervals from the Well BP-01 (Imbé Formation), drilled by in the Pelotas Basin offshore. We identified 66 dinoflagellate cyst taxa, 47 of them belong to the Order Gonyaulacales and 19 to the Order Peridiniales. The relative abundance data highlight two different dinoflagellate ecogroups represented by Apectodinium and Enneadocysta in the intervals A and B, respectively. The level with the highest percentages of Apectodinium recorded in the Calcareous Nannofossil Zone N-410 (Ypresian), suggest that the Apectodinium maximum represents the Early Eocene Maximum Thermal Event (EMT-2). Enneadocysta Acmes registered near the Bartonian/Priabonian boundary, can be correlated with a drop in sea surface temperature that occurred after the Mid-Eocene Climatic Optimum. Dinoflagellate occurrences suggest deposition in open sea conditions during the transgressive phase. The P/G ratio does not reach significant values in the analyzed intervals, indicating low dissolved nutrient concentrations.
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Articulos(INGEOSUR)
Articulos de INST.GEOLOGICO DEL SUR
Articulos de INST.GEOLOGICO DEL SUR
Citación
Premaor, Eduardo; Ferreira, Elizabete P.; Guerstein, Gladys Raquel; Alves de Souza, Paulo; Eocene paleoceanographic and paleoclimatic events recognized by assemblages of dinoflagellate cysts in the Southwest Atlantic Ocean; Pergamon-Elsevier Science Ltd; Journal of South American Earth Sciences; 130; 104587; 10-2023; 1-20
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