Executive Summary : | Naga Hills, a significant part of the Tertiary Assam-Arakan basin, is divided into three linear NE-SW extending zones: Ophiolites in the east, belt of Schuppen in the west, and Inner fold belt in between. The Belt of Schuppen, the most notable morphotectonic unit of Naga Hills, extends over 4,500 km2 and is flanked by Disang and Naga thrusts in the south-east and northeast respectively. The Naga schuppen belt is significant as it forms the hinge zone of the shelf-to-basinal slope of the basin. In the early Neogene, Surma Group was deposited over Barail Group. The 300-900m thick Surma sediments are divided into Bhuban and Bokabil Formations, characterized by thin alternations of shales, siltstones, and sandstones. Workers have varied opinions on the depositional environment of Surma sediments, with some suggesting a fluvio-deltaic and estuarine setup, while others suggest a delta plain to delta front environmental setup. The proposed study area covers the Belt of Schuppen in Chumukedima district, Nagaland, where remarkable outcrops of Barail, Surma, and Tipam Groups, along with Dihing Boulder beds and Dupitila sediments, are exposed. The area lies near oil seepages in Seithekema and other oil/gas fields of the Assam shelf, bearing economic significance. Previous studies of Neogene rocks in the proposed area have done primary stratigraphic, lithologic, and palynologic studies, but there is a lack of detailed sedimentological, geochemical, and sequence stratigraphic analysis. This study would help understand the petroleum potential of Surma and Tipam Groups in the proposed area. |