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摘要
The formation and distribution of the mantle derived CO2 gas pool has great relationship of the faults. The mantle derived CO2 was mostly induced by mantle degassing by paleo Pacific Plate subduction in Early Cretaceous 143Ma and 124Ma, partial melting and upwelling of mantle in similar to 43Ma, 24 similar to 15Ma, and 8 similar to 4Ma. Also the degassing by alkaline basalt magma in similar to 43Ma, 24 similar to 15Ma, and 8 similar to 4Ma generated many mantle derived CO2. They dispersed and accumulated by different level faults. The Tanlu Fault, lithospheric fault of the study area, is the most important fault to gas's dispersion and accumulation, while the crustal fault like detachment faults and transfer faults acted as secondary important faults to the gas dispersing and accumulation. The shear or extension of these faults in Early Cretaceous 143 Ma and 124Ma, Cenozoic similar to 43Ma, 24 similar to 15 Ma, and 8 similar to 4Ma as well as the synsimultaneously alkaline basalt magma action controlled the formation, migration and accumulation of the mantle derived CO2 gas. Different level faults intersected and formed channel to gas, while the detached depth of the detachment faults (where is also the low velocity zone developed) and the decollement faults transferred by the disconformity and unconformity in cover are very important horizontal channels. In Early Cretaceous, mantle degassing CO2 by plate subduction dispersed and accumulated along the Tanlu fault. Controlled by the change of subduction direction and rate of the Pacific Plate to Eurasian Plate, mantle degassing CO2 induced by partial melting of the mantle migrated along the Tanlu Fault. Meanwhile, the Tanlu Fault cut gradually deeper into the mantle in similar to 43Ma, 24Ma and 8Ma (or 5Ma), which induced mantle magma degassing and derived CO2 gas. The mantle degassing CO2 gas migrated upwards along the fault due to Tanlu Fault strike slipping in Cenozoic, and converged to those gases from magma degassing in detached zone (also the low velocity zone). Then these gases migrated horizontally through the low velocity zone to the basement and cover. They accumulated to gas pools by relaying transmission along the decollement fault zone and steep fault zone. This study predicated that the area adjacent the Tanlu Fault may be the potential zone to the inorganic oil and gas.
- 出版日期2016-7
- 单位中国石油大学（北京）; 中国科学院地质与地球物理研究所; 中国科学院地质与地球物理研究所兰州油气资源研究中心
