title: Organic-rich shales as archive and resource for microbial extremophiles
abstract: Organic-rich shales of sedimentary basins are the most abundant carbon-rich rocks throughout the world, formed as a consequence of different geological events. The repetitive sedimentation of the mudstones, clay particles, biological organic matter, microbial decomposition of the organic matter, and evaporation formed organic-rich shales of diverse origins in different geological eras. These organic-rich shales are an important source of gas, oil, and occasionally precious metals such as copper,