Paleomires of Eocene Lignites of Bhavnagar, Saurashtra Basin (Gujarat), Western India: Petrographic Implications

• DOI: 10.1007/s12594-017-0658-z
• Publication Date: 2017-07-20T07:39:36Z
• Authors: Prakash K. Singh; Vijay K. Singh; M. P. Singh; P. K. Rajak
• Keywords: Saurashtra

ABSTRACT The Tertiary basins of Gujarat have always been a potential target for their hydrocarbon resources. The lignite resources of the region have also been an important field of research. The present paper presents the results of the petrological study carried out on the lignites of the Saurashtra basin. For this purpose samples were collected from lower and upper lignite seams from the Surkha lignite mine of Bhavnagar, Saurashtra. These samples were subjected to detailed petrographic analysis (both maceral and microlithotype). The study reveals that these lignites are dominantly composed of huminite group macerals while liptinite and inertinite group macerals occur in subordinate amounts. These lignites have attained a thermal maturity up to 0.28-0.30 percent vitrinite reflectance (VRr) which classifies them as ‘low rank C’ coals. Moreover, Bhavnagar lower lignite seam shows relatively less gelification as compared to the upper seam which suffered relatively more biochemical degradation. These lignites are characterized by high gelification index (GI) and low tissue preservation index (TPI). With the help of petrography based facies models an attempt has been made to reconstruct the environment of the paleomire of these lignites.