PALEOENVIRONMENTAL CONDITIONS THAT RESTRICTED THE NEOGENE BASIN OF CHELIF: A CASE STUDY FROM DJEBEL MENI

Abstract

The quantitative analysis (paleoecologic indexes) and the qualitative ones ( set of associations) reflect to a large extent the coherence and consistence between them. In the lower and the middle parts the Pelagism index shows an opened on toward the offshore with the high specific diversity and equitability. So that, this indicates a well conditions of the environment attested by species diversity of benthic foraminifera that profiler in subtidal to the offshore. Moreover, the summit of the section shows a decline of the curve, materialized by the diminish of the benthic foraminifera. A low equitability index and the ratio Bolivina/ Bulimina is in the favour of the former. The first and the second paleoecologic unites designate the dominance of some specific taxons, so that, the environment is so restricted characterized by reduction of the bathymetric with a low water oxygenated and lutites influx.