High amounts of C27 steranes, regular steranes, 4-methyl steranes, long chain tricyclic terpanes for the western Qaidam oils indicate that the dominant organic matter source is algal material.

• 具有高含量的C27甾烷、规则甾烷、4-甲基甾烷、长链三环萜烷，说明它们母质主要为菌藻类；