Cenozoic magmatic activity and oblique uplifting of the Ailao Mountain: Evidence from a short-period dense seismic array  

作　　者：Lu ZHANG Zhiming BAI Tao XU Zhenbo WU Minfu HUANG Guiping YU Junlei CHEN Mengjie ZHENG 

机构地区：[1]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China [4]CAS Center for Excellence in Tibetan Plateau Earth Sciences,Beijing 100101,China [5]School of Geophysics,Chengdu University of Techonology,Chengdu 610059,China [6]Earthquake Administration of Yunnan Province,Kunming 650224,China

出　　处：《Science China Earth Sciences》2020年第9期1294-1308,共15页中国科学（地球科学英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2016YFC0600302);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0701);the National Natural Science Foundation of China(Grant Nos.41774097,41674064,41704042&41574082)。

摘　　要：Geological studies show that the southern part of Ailaoshan-Red River shear zone(ALSRRSZ)has experienced complex metallogenic processes and multi-stage non-uniform uplifting,called oblique uplifting since the Cenozoic.To detect the deep structure and geodynamic background beneath Daping,Chang’an and other gold and polymetallic deposits in this area,we carried out a high-density short-period seismic array survey in southern Yunnan province.The array used is approximately240 km long with an interval of 500 m between two adjacent stations.Based on the data collected by the array,we used H-κstacking and common conversion point(CCP)methods of receiver functions to reveal the fine crustal structure beneath this array,which was located from Lvchun(western end)to the east and ended in Maguan.The three main conclusions are as follows.(1)The average crustal thickness is approximately 37 km and the Vp/Vsratio is 1.75.However,the thickness and Vp/Vsratio of the Ailao Mountain are rather greater or higher than those of the western Lanping-Simao Basin and eastern South-China block.These results may indicate that the crust is rich in ferromagnesian minerals or has a thermal fluid anomaly after orogenic movement.(2)There are two obvious inclined interfaces beneath the Ailao Mountain in the mid-upper crust,which suggests that strong deformation occurred there during the orogenic period.Some evidences,such as the weak converted-wave Pms phase from the Moho,low P-wave velocities of the upper mantle,high surface heat flow values,and generally developed hot springs,indicate that a strong crust-mantle interaction exists in the southern segments of the Ailaoshan-Red River shear zone.These interactions include a diapir of mantle-sourced magma(stronger in the east than that in the west),lateral collision from the Indian Plate,and the differential uplift caused by the strike-slip movement of the Red River Fault.All of above deep processes led to the Cenozoic oblique uplifting of Ailao Mountain.(3)By combining the location of the deposi

关 键 词：Ailaoshan-Red River shear zone Multiform metal deposits Oblique uplifting Short-period dense seismic array Receiver function 

分 类 号：P315[天文地球—地震学] P542[天文地球—固体地球物理学]