Distribution and characteristics of rearranged hopanes in the black shale of the Chang 9 member, the Upper Triassic Yanchang Formation in the Ansai area, Ordos Basin, North China.

ABSTRACT: Shale samples from source rocks of the Upper Triassic Yanchang Formation (Chang 9 member) in the Ansai area, Ordos Basin, North China, were analyzed using gas chromatography - mass spectrometry (GC-MS) to investigate the distribution, abundance, and enrichment mechanisms of rearranged hopanes. Four rearranged hopane series were detected, with all four present simultaneously in individual samples. Analysis of the C₃₀ hopane series (regular C₃₀H, diahopane C₃₀D, and neohopane C₃₀E) using a ternary diagram revealed a distinct linear trend, demonstrating a systematic, inverse relationship between the abundance of regular hopane and the combined abundance of its rearranged counterparts. These results provide strong evidence that C₃₀D and C₃₀E in the Chang 9 shales are diagenetic products derive

SUBMITTER: Yue H 

PROVIDER: S-EPMC12668623 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature