Fault and Magmatic Activity as Control of Mantle Source CO₂ Gas Accumulation: A Case Study of Jiyang Depression

In the shallow level of the earth's crust, migration and accumulation of CO₂ are similar to those of conventional hydrocarbon, and both demand rich sources, reservoirs, traps, migration system and caprocks. However, CO₂ is greatly different from hydrocarbon in origin and source. By research for deep faults and igneous rocks related to CO₂ gas fields, the author considers that magma is the carrier for CO₂ gas migration, while the development of igneous rocks is an important sign of the synchronous fault spatio-temporal activity. The 'migration' is one of the most important elements for mantle source CO₂ gas accumulation, which means that there are deep faults connected to the mantle, directly or indirectly, and fault activity must be consistent with CO₂ gas migration in space and time. Thus formation of CO₂ gas fields is closely related tofault and magmatic activity. Control of the fault in the formation of CO₂ gas fields is as follows: (1) deep faults control CO₂ gas accumulation belts; (2) the boundary faults and their derivative faults at different directions and different scales control the formation and distribution of CO₂ gas fields in the basin.