• 责任者：Tan Xibin (Key Laboratory of Active Fault and Volcano ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Li Yuanxi
• 刊名：Seismology and Geology
• 出版年：2013
• 卷期：35(3)
• 关键词：活动构造 ; active tectonics ; 推覆构造 ; nappe structure ; 龙门山断裂带 ; Longmenshan Fault Zone
• 页码：p.506-517
• 图表：6 illus., 1 table, 21 refs.
• 分类号：0300
• issnNo：ISSN0253-4967
• isbnNo：CN11-2192/P

     The Longmen Shan,located at the eastern margin of the Tibetan plateau,is a steep and high ex- humation area. In recent years,the 2008 Wenchuan Mw 7.9 earthquake and the 2013 Lushan Ms7.0 earthquake occurred,and researchers presented a lot of low-temperature thermochronology data of the Longmen Shan and adjacent area. In this paper,we provide 4 ZFT ages and 4 AFT ages for the south- ern segment of the Longmenshan Thrust Belt（LTB） ,where the low-temperature thermochronology data are still few. Combining with previous researches,we get the Cenozoic exhumation history of the Baox- ing Massif,located at the southern segment of the LTB ,and new knowledge about the Cenozoic activity of the southern segment of the LTB. The Baoxing Massif began quickly cooling in the early Cenozoic, with the cooling range exceeding 225℃ ,while the cooling range of the Pengguan Massif in the central segment of the Longmen Shan is between 185 - 225℃. The four AFT ages in the Baoxing Massif are between 2.7 -5.0Ma,which are younger than that in the Pengguan Massif, and it indicates that the late-Cenozoic cooling rate of the Baoxing Massif is bigger than that of the Pengguan Massif. Under this assumption that the surface temperature is 15℃ and the paleo-geothermal gradient is 30℃/km, the average exhumation rate from 3 - 5Ma to present is about 0.63 - 1.17mm/yr. The low-temperature thermochronology data indicate that the differential exhumation is concentrated in the Beichuan-Yingx- iu Fault and the Jiangyou-Guanxian Fault in the central segment of the LTB,while it is dispersed in a wider region along the two branches of the Shuangshi-Dachuan Fault and the faults and folds to the east.in the southern segment.