Molecular and Compound-specific Isotopic Composition of Hydrocarbons in Lower Cambrian Black Shales from the Yangtze Platform, South China

First molecular and compound specific isotope data for carbonaceous matter in mineralized Lower Cambrian black shale from the margin of the Yangtze Platform in South China indicate the presence of marine, biogenic, very mature bitumen that was derived from algae and various bacteria (including cyanobacteria) in a marine, in places saline, restricted basin. No systematic differences were noted between finely dispersed bitumen (bulk of carbonaceous shale) and discrete, black bitumen nodules, but differences in the molecular and isotopic composition between samples point to variation in the source.