Calcareous Nannofossil Assemblages of Tonasa Formation Palakka Area, South Sulawesi: Implication of Paleoenvironmental application

Abstract

Tonasa limestone formation in this area consists of interbedded between marl and limestone, which were developed intensively in the marine environment from the Late Eocene to Oligocene. One important component of this rock is Calcareous nannofossil as the primary production of CaCO3. The aim of this study are to obtain data from the distribution of calcareous nannofossil, assemblages and early investigation about the implications for the paleoenvironment. Calcareous nannofossil is a good indicator for determining paleoenvironmental conditions such as modern coccolithophores that show seawater stratification. The material under study came from the outcrops of the Barru River, which were collected by measuring section method, then the samples were prepared using the smearslide technique. The result are the presence some marker species such as Sphenolithus distentus, Distyococcites bisectus, Zygrhablithus bijugatus, Phontosphaera enormis, Cyclicarg, olithus abisectus, Sphenolithus predistentus, Discoaster saipanensis, Spenolithus pseudoradians. The presence of Discoaster as typical warm water organism characterize the deep photic zone, therefore indicates stratified water colomn as well as deepened nutricline.