Sedimentology, Sequence Stratigrapphy and Geochemical Investigations of Early Eocene Nammal Formation, Salt Range, Pakistan (T-1420) (MFN 5639)

Abstract

Eocene carbonate rocks show good outcrop exposures for the sedimentological studies in the Salt Range. In the present research work, Nammal Formation of Eocene age is selected for detailed sedimentological studies and depositional setting. Detailed Sedimentological studies were carried out based on data from 3 different stratigraphically important sections in the Salt Range from East to West (Tatral, Bestway Quarry near Katas, Nammal Gorge). Lithologically, the formation consists of interbedded nodular limestone, Marl and Shale. The Microfacies identified are mudstone, wackstone to packstone and grainstone in a fine grained matrix with abundant bioclasts of benthic foraminifera. The Nammal Formation presents retrogradational facies suggesting the Transgressive System Tract (TST). The Nammal Formation belongs to inner neritic environments because it contains larger benthic foraminifera in large quantities as compared to Planktons and Nano-fossils belonging to genera Lockhartia, Assilina, Nummulites, Alvolina and Discocylina that are characteristic of shallow shelf environment. It suggests a carbonate platform deposition. Digenetic features such as partial to complete neomorphism, obliteration of tests of foraminferas, secondary cementation and partial dolomitization are observed in thin sections and outcrop studies. The TOC studies of 9 samples of shale and limestone were carried out. The TOC values are 0.0812. This suggests that no organic matter is present in Nammal Formation and has no Source Rock Potential. Lack of TOC may be caused by the oxidation of organic matter from the shale. Outcrop samples were used rather than core samples for analysis.