Microscopic Characteristics of Microbially Induced Sedimentary Structures from Yunmengshan Formation in Jiaozuo,North China

摘要

INTRODUCTION The Precambrian biosphere includes almost exclusively microbiota. For at least 3 billion years, benthic microbiota have colonized sandy substrata in shallow-marine settings and formed biofilms or microbial mats. Activities of benthic prokaryotes in response to the sedimentary dynamics could form the characteristic structures known as "microbially induced sedimentary structures (MISS)", arising syndepositionally from the interactions of biofilms and microbial mats with the sedimentary grains due to the variations in hydraulic parameters in siliciclastic aquatic environments. Microbial mats/films influence the depositional fabric of clastic deposits across a wide range of physical, chemical and biological processes. From the Early Archean, extensive microbial mats widely overgrew on large areas of the ancient seafloors, forming organic carpets in shallow-marine environments.