Depositional environment variations and organic matter accumulation of the first member of the Qingshankou formation in the southern Songliao Basin, China

The organic-rich shale in the first member of Qingshankou Formation, which is located southern Songliao Basin, regarded as a high-quality source rock East China. Geochemistry parameters were utilized to illustrate formation and preservation conditions Qing1 Member Changling Sag, Basin. In present study, from longitudinal continuity, samples organic geochemistry elemental collected systematically analyzed. This aims at determining paleosalinity, paleoclimate, paleoredox conditions, paleoproductivity reconstructing its depositional paleoenvironment. According total carbon (TOC) content, Sag can be classified into two intervals, are lower part upper part, with high TOC content low respectively. It proved results geochemical indicators that under warm humid climatic relatively was generated anoxic environment. Terrigenous input brought nutrients water body lake, made algae flourish, had imposed vigorous impact on accumulation matter. mainly deposited weakly oxidizing gradually enhanced oxidation reduced productivity. contrast shale, terrigenous inflow low. has positive relevance well paleosalinity indicating good favorable for A model proposed matter this shale. hot dry degree enrichment, whereas terrestrial primary productivity lake basin enrichment.