黑料网

Abstract

A detailed study of the Middle to Late Eocene outcropping series of an onshore well in central Tunisia (PK1) yielded ostracod species in 45 samples from the Souar formation. The ostracod assemblage of the entire section belongs to the Southern Tethyan Type showing distinct changes up section. An R-mode hierarchical cluster analysis of the total association of ostracod was computed using the Jaccard coefficient of similarity (the paired group average method); species were statistically discriminated into four different clusters each of them with its particular paleoenvironments: Group I characterized by the presence of species Loculicytheretta cavernosa, Reticulina proteros, Isobuntonia pseudotuberata and Costa libyaensis indicators of shallow waters; groups II and III mainly composed of species common in deep environments like Paleocosta makattamensis, Cytherella angulata, Loxoconcha vetustopunctatella and Soudanella laciniosa reticulata; group IV made by species typical of deep with low dissolved oxygen environments such Hermanites libyaensis, Bairdia tarabulusensis, Cytheropteron sp., Xestoleberis kenawyi, Soudanella laciniosa triangulate and Buntonia ramosa. Detrended correspondence analyses (DCA) applied to the same data led to the distinction of two important environmental factors affecting the distribution of these ostracod assemblages in the study area: Water depth and oxygenation of water. Paleoecological model based on ostracods associations were developed, identifying respectively characteristics associations for neritic zones and external platform for the Middle and Upper Eocene deposits of PK1.

Biography

Email: amamiaida@gmail.com