Geochemistry and depositional environment of fresh lacustrine source rock: A case study from the Triassic Baijiantan Formation shales in Junggar Basin, northwest China

摘要

Highlights?Sedimentary environments are low salinity to freshwater lacustrine.?Good source rocks are both Type II and Type III and mainly generate oil.?Organic matter input is derived from plankton, algae and terrestrial organisms.?Biomarkers are related to organic matter source, salinity, redox and maturation.AbstractThe shales in the Baijiantan Formation are considered to be an important potential source rock in the Junggar Basin. To evaluate this basin’s source-rock characteristics, 61 core samples from 14 boreholes were analyzed using total organic carbon and total sulfur analyses and Rock-Eval pyrolysis. Thirty-two core samples were analyzed using solvent extraction, column fractionation, biomarker analysis and the organic petrology of kerogen. The results suggest that the shales in the Baijiantan Formation have fair to excellent hydrocarbon generation potential, and the organic matter types include both Typ