INVESTIGATION OF BENTHONIC FORAMINIFERAL ASSEMBLAGES FROM THE THAR COAL BASIN, SINDH, PAKISTAN

Abstract

The foraminiferal studies of the Thar coal Basin Sediments have been carried out on samples samples from 10 bore holes. Out of 100 samples from 10 holes only 30 samples from 6 holes contains benthic foraminifera and the remainder are barren. No Planktonic forams were recorded during this study. Most of the benthic forams are agglutinated and in general are of small in size. The preservation of the fauna is rather poor; most specimens are strongly recrystallied and partly crushed. The assemblage is comprised of specimen belonging to the genera Haplophragmoides, Ammobaculites, Trochammina, Osangularia Ammosphaeroidina together with the rare occurrence of calcareous benthic forams. The total assemblage indicates deposition in shallow, inner neritic marine water. Sediments are dark gray shales with abundant organic matter and subordinate sandstone, the depositional environment probably was one of poorly oxygenated, slow moving bottom water with high CO2 content resulting from the decomposition of organic matter. Stratigrahic data derived from the foraminifera indicate the Coal-bearing rocks of the Thar Coal field to be late Paleocene to Early Eocene in age.