Microbially originated wrinkle structures on sandstone and their stratigraphic context: Palaeoproterozoic Koldaha Shale, central India

Wrinkle morphology has been classified and an attempt has been made to understand the origin of each of the varieties, and to visualize the processes that acted upon the microbial mats to produce the wrinkle structures in their specific palaeogeographic context. The general palaeogeographic bias in occurrence of the sandy wrinkles is well reflected in their concentration in the lower part of the highstand systems tracts (HST's), one superposed above the other, comprising the Koldaha Shale. The smaller-scale palaeogeographic control is indicated by compartmentalization of two wrinkle varieties in the upper and the basal intervals of the HST's, and overlapping occurrence of other varieties in the medial interval with apparent preference for either the upper or the lower levels.