Petrographic observations suggestive of microbial mats from Rampur Shale and Bijaigarh Shale, Vindhyan basin, India

摘要

Petrographic observations of two Vindhyan black shales (Rampur Shale of the Semri Group and Bijaigarh Shale of the Kaimur Group) revealed the following features: 1. general wavy lamination, 2. contorted and folded thin shreds of organic matter, 3. wavy pyritic laminae. 4. 'teeth and socket' structure. These features are indirect evidence of microbial mat colonization during the Proterozoic. The microbial mats probably fixed carbon at the sediment surface, stabilized sediment and recycled organic matter and were the primary producers, unlike during the Phanerozoic time.