EOCENE-OLIGOCENE PLANKTIC FORAMINIFERA OF THE WEST AFRICAN MARGIN IN CASAMANCE: BIOSTRATIGRAPHY AND PALEOECOLOGY
Micropaleontological analysis of cuttings and core samples from boreholes of the West African Basin (Casamance) allow the stratigraphical framework and paleoecology settings during the Eocene-Miocene stratigraphical interval to be recognized. Planktic foraminifera from limestones and marly deposits reveal a succession of planktic foraminiferal biozones. The Early Eocene was defined by the occurrences of Pseudohastigerina wilcoxensis, Morozovella formosa, M. subbotinae and other morozovellinids. The occurrences of Acarinina bullbrooki and Subbotina yeguaensis in Boconta Formation indicate the middle-upper Eocene stratigraphical interval. Abundant Globigerina primordius and Paragloborotalia semivera in the western region document the presence of Oligocene sedimentary rocks. The distribution of the surface and deep waters planktonic foraminiferal assemblages is indicative for the environmental events that resulted in changes in sea surface temperatures. The general climatic setting evolved from warm to cold waters during the Eocene/Oligocene turnover; in parallel sedimentation shifted from carbonate to detrital. These changes could be correlated to the globally recognized cold events in the water mass.
Auteur(s) : Malick THIAM
Pages : 1-23
Année de publication : 2013
Revue : Nova Science Publishers, Inc.
Type : Article
Mise en ligne par : THIAM Malick