Advances in Earth Science ›› 2021, Vol. 36 ›› Issue (4): 421-441. doi: 10.11867/j.issn.1001-8166.2021.045
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Fangbin LIU 1 , 2 , 3( ), Junsheng NIE 1 , 2( ), Dewen ZHENG 4, Jianzhang PANG 5
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Fangbin LIU, Junsheng NIE, Dewen ZHENG, Jianzhang PANG. The Cenozoic Exhumation History and Forcing Mechanism of SE Tibetan Plateau: A Case Study of the Lincang Granite Area[J]. Advances in Earth Science, 2021, 36(4): 421-441.
As an important part of the Tibetan Plateau, the SE Tibetan Plateau experienced significant tectonic uplift, fault activity, climate change, and river system reorganization during the Cenozoic and these processes were accompanied with rapid rock exhumation. Therefore, the SE Tibetan Plateau has become one of the hottest areas of research focus. However, great debate exists regarding the exhumation process and forcing mechanism of the SE Tibetan Plateau during the Cenozoic. Therefore, we select the Lincang granite of the SE Tibetan Plateau as the research area. Firstly, we reconstruct the Cenozoic exhumation history of the Lincang granite area, based on multi-system low temperature thermochronology [including apatite (U-Th)/He, zircon (U-Th)/He and apatite fission track] and thermal history modeling. Secondly, we explore possible forcing mechanisms for the recorded several phases of rapid rock cooling in this area by integrating regional climatic and tectonic data. The preliminary conclusions are as follows: ① The Lincang granite area experienced three phases of rapid exhumation during the Cenozoic (late Eocene, Oligocene and middle Miocene). ② Combined with regional climate and geological data, we suggest that the late Eocene rapid cooling event of Lincang granite area was mainly caused by crustal shortening, and the Oligocene rapid cooling event was associated with crustal shortening and lateral extrusion. The occurrence of these two events may be inevitably connected with the oblique subduction of the Indian plate. In contrast, the middle Miocene rapid cooling event was closely related to the Asian summer monsoon intensification. The intensified monsoon precipitation would have likely increased the power of river incision, which accelerated the geomorphic evolution of this region.