科研之友
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摘要
Jiangnan Uplift located in the collision zone between Yangtze and Cathaysia block is the key to interpret the tectonic evolution of Smith China block. The Cenozoic thermal history and the uplift processe of Mufushan pluton are constrained by the combination of analysis of apatite fission track and (U-Th-Sm)/He ages with modeling of fission track length distribution. Based on analysis of thermochronological dating, the authors probed into the relationship between the thermochronological evolution and the tectonic development combining with regional tectonic settings. The exhumation of plutons arrived at about 4800 m since 80 Ma, and the uplift processes were not uniform in space, and different plutons had somewhat different uplift processes. Thermal history modeling of the AFT data shows, that the Mufushan pluton experienced three episodes of cooling event, two of which exhumed rapidly happened in Upper Cretaceous-Paleocene (about 80 similar to 50 Ma) and Upper Miocene (since 10 Ma). There is a period of relative thermal stability at 50 similar to 10 Ma and exit the PAZ. The first stage of rapid uplifting during 80 similar to 50 Ma in this region is coeval with extension episode of Mid-Lower Yangtze during Himalayan which resulted in the formation of fault basin and exhumation of shoulder block; the Upper Miocene rapid cooling since 10 Ma is attributed to the westward movement and subduction of Pacific plate. The uplift and exhumation of Mufushan pluton since Late Yanshanian led to a good deposition response in basins and the cooling events of three phases just coincided with the regional tectonic settings of study area.
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单位中国科学院; 中国科学院大学
