The growth index of a fault is related not only to its activity rate but also to the deposition rate, especially in seriously truncated area, the growth index is serious distorted. But this situation has been neglecte...The growth index of a fault is related not only to its activity rate but also to the deposition rate, especially in seriously truncated area, the growth index is serious distorted. But this situation has been neglected for a long time. Based on growth index and fault activity rate, the activity intensity of Linnan fault is studied, and it is so considered that the conclusion of latter is right. The speed of activity of a fault can be directly attained from the duration of sedimentation and reflects quantitatively the activity intensity of the fault, thus the terminology of the growth index of fault is practically meaningless. Fault activity was strong during Dongying time, and the buried depth of stratum is shallow, so fault sealing is worse, hydrocarbons migrated to Qianguantun and Qudi areas. This is important to hydrocarbon accumulation. Fault activity intensity was big during Minghuazhen time, which determined the vertical hydrocarbon distribution.展开更多
Whole-rock Rb-Sr, zircon U-Pb and hornblende, biotite and K-feldspar K-Ar ages areused to reconstruct the cooling history of the Huangmeijian intrusion in the Anqing-Lujiangquartz-syenite belt in Anhui. Oxygen isotope...Whole-rock Rb-Sr, zircon U-Pb and hornblende, biotite and K-feldspar K-Ar ages areused to reconstruct the cooling history of the Huangmeijian intrusion in the Anqing-Lujiangquartz-syenite belt in Anhui. Oxygen isotope geothermometry of mineral pairs demonstrates thatdiffusion is a dominant factor controlling the closure of isotopic systems. Assuming the coolingof the intrusion is synchronous with a dicrease in local geothermal gradients, an emplacementdepth of about 8 km and the magma crystallization temperature of 800±50℃ are estimated. TheHuangmeijian intrusion experienced a rapid cooling process and uplifted after its emplacementand crystallization at 133 Ma B.P. with a cooling rate of 34.5℃/Ma and an uplifting rate of 0.35mm/a. The intrusion was rising until it rested at a depth of 3km at a temperature of 300±50℃about 14 Ma later. Then the intrusion was in slow cooling and uplifting with a cooling rate of4.4℃/Ma and an uplifting rate of 0.04 mm/a. U-Pb dating of pitchblende is done for the hydrothermal uranium deposit formed in thecontact zone of the Huangmeijian intrusion. The result shows that the mineralization age is closeto the closing time of the K-Ar system in biotite. The fluid inclusion thermometry indicates thatthe mineralization temperature is in agreement with the closure temperature of the biotite K-Arsystem. This suggests a close relationship between the slow cooling of the intrusion and thehydrothermal uranium mineralization process.展开更多
文摘The growth index of a fault is related not only to its activity rate but also to the deposition rate, especially in seriously truncated area, the growth index is serious distorted. But this situation has been neglected for a long time. Based on growth index and fault activity rate, the activity intensity of Linnan fault is studied, and it is so considered that the conclusion of latter is right. The speed of activity of a fault can be directly attained from the duration of sedimentation and reflects quantitatively the activity intensity of the fault, thus the terminology of the growth index of fault is practically meaningless. Fault activity was strong during Dongying time, and the buried depth of stratum is shallow, so fault sealing is worse, hydrocarbons migrated to Qianguantun and Qudi areas. This is important to hydrocarbon accumulation. Fault activity intensity was big during Minghuazhen time, which determined the vertical hydrocarbon distribution.
文摘Whole-rock Rb-Sr, zircon U-Pb and hornblende, biotite and K-feldspar K-Ar ages areused to reconstruct the cooling history of the Huangmeijian intrusion in the Anqing-Lujiangquartz-syenite belt in Anhui. Oxygen isotope geothermometry of mineral pairs demonstrates thatdiffusion is a dominant factor controlling the closure of isotopic systems. Assuming the coolingof the intrusion is synchronous with a dicrease in local geothermal gradients, an emplacementdepth of about 8 km and the magma crystallization temperature of 800±50℃ are estimated. TheHuangmeijian intrusion experienced a rapid cooling process and uplifted after its emplacementand crystallization at 133 Ma B.P. with a cooling rate of 34.5℃/Ma and an uplifting rate of 0.35mm/a. The intrusion was rising until it rested at a depth of 3km at a temperature of 300±50℃about 14 Ma later. Then the intrusion was in slow cooling and uplifting with a cooling rate of4.4℃/Ma and an uplifting rate of 0.04 mm/a. U-Pb dating of pitchblende is done for the hydrothermal uranium deposit formed in thecontact zone of the Huangmeijian intrusion. The result shows that the mineralization age is closeto the closing time of the K-Ar system in biotite. The fluid inclusion thermometry indicates thatthe mineralization temperature is in agreement with the closure temperature of the biotite K-Arsystem. This suggests a close relationship between the slow cooling of the intrusion and thehydrothermal uranium mineralization process.
