Organic Geochemical Characteristics and Thermal Evolution Characteristics of Paleogene to Neogene Source Rocks in Mangai Area, Qaidam Basin

The Paleogene-Neogene lacustrine source rocks in the Mangai area of the Qaidam Basin are significant exploration targets. A comprehensive evaluation of four major intervals (E$_3^2$, N$_1$, N$_2^1$, N$_2^2$) was conducted through systematic organic geochemistry, maceral identification, thermal maturity analysis, and burial-thermal history modeling. Results show TOC contents of 0.203~1.28% (avg. 0.74%), chloroform bitumen "A" of 0.0164~0.2495% (avg. 0.132%), and total hydrocarbon contents of 69.29~1637.48 $\mu$g/g (avg. 853.39 $\mu$g/g), indicating fair to good quality. Kerogen elemental analysis (H/C=0.97~1.21), maceral composition (sapropelinite+exinite=70~98%), and saturated hydrocarbon chromatography…