Trace Fossils and Microbial Mat- Induced Sedimentary Structures from the Girbhakar Sandstone of Marwar Supergroup, Bhopalgarh Area, Jodhpur, Rajasthan, India

V.S. Parihar*, V. Gaur and S.L

Abstract

Well-preserved trace fossils (Thalassinoides isp, Planolites isp. and Palaeophycus isp) and Microbial mat -induced sedimentary structures are reported from Girbhakar Sandstone of Marwar Supergroup, the upper sequence of Jodhpur Group. The trace fossils are preserved in fine grained sandstone and ferruginous sandstone, where as mat -induced sedimentary structures are, occur in patches on the top of fine grained sandstone bedding surface. The area under present investigation lies around Bhopalgarh, which is 70 km northeast of Jodhpur. All these ichnogenera shows marine and shallow marine to sub-tidal depositional environment. No age can be assigned on the basis of these trace fossils as they range from Cambrian to Recent but the presence of microbial mat-induced sedimentary structures are Ediacaran affinity and can be assigned Ediacaran age to Girbhakar Sandstone of Bhopalgarh area included in Girbhakar Sandstone Formation.