CO₂碳同位素等地球化学特征显示，松辽盆地南部多处发现的高含量CO₂气藏属于无机成因天然气。通过对盆地深部壳幔结构、深部热异常分布及长岭断陷火山活动等的综合研究，认为：松辽盆地深部热流异常的分布区是幔源气体的源头，而中上地壳的低速高导体是把地幔流体中CO₂通过壳内火山岩浆活动输送到盆地地层的中转站；长岭断陷在断陷期形成的大规模火山，为盆地晚期幔源气提供了储存空间；无机气具有晚期成藏特征，长岭地区与乾安—前神字井控陷断裂上盘的大型火山岩体是无机成因CO₂聚集的主要区域。

Geochemical indexes indicate that the gas reservoirs with high CO₂ content in many parts of Southern Songliao Basin belong to inorganic-origin gas. According to the study of the tectonic characteristics of deep layers, the distribution of heat flow piercement and the main fault system in the Changling depression, this paper concludes that the heat flow piercement is the source of mantle resources, the low velocity and high conduction zone in the deep layer of Songliao Basin is a midstation for transferring mantle derived carbon dioxide into the shallow reservoir, and large volcanic activities during rift faulting are the most important reservoir of inorganic gas. And the inorganic CO₂ is mainly distributed in the large lava adjoining to the Changling and Qian’an Qianshenzi fault.