Attributes and evolution of the eastern massif in the Qinghai-Tibetan Plateau

doi:10.13745/j.esf.sf.2023.2.5

Abstract

Abstract:

Using high-quality seismic data collected from a large number of local seismic stations, we have achieved high-resolution imaging of the three-dimensional velocity structure of the crust and upper mantle in the Qinghai-Tibetan Plateau with an accuracy of 0.5°×0.5°×10 km, which revealed in great detail the crustal and upper mantle structure of the Qinghai-Tibetan Plateau and provided new evidence for understanding the dynamics of continental collision and plateau evolution. Then, based on the 3D seismic P-wave velocity data, a 3D depth map of the lithosphere-asthenosphere boundary beneath the Qinghai-Tibetan Plateau is obtained. It is found that there are fundamental differences in geological attributes between the eastern and western parts of the plateau: The eastern part is dominated by thick lithosphere with high wave velocity, high resistivity and density, and a thickness range of 150-180 km; whereas the west is dominated by thin lithosphere with low wave velocity, low resistivity and density, and thickness ranging between 130-155 km. Furthermore, there is no large-scale asthenospheric upwelling in the eastern part whereas ~20-30 km upwelling has occurred in the west. The coordinates of the two endpoints of the east-west boundary are (20°N, 85°E) and (40°N, 98°E) respectively. According to the paleomagnetic data, the eastern massif in the Qinghai-Tibetan Plateau is a stress transition zone situated between the western continent-continent subduction zone and Southeast Asia ocean-continent subduction zone since 40 Ma.

Key words: Qinghai-Tibetan Plateau, eastern massif, seismic tomography, lithospheric thickness, attribute evolution

CLC Number:

P313.1

LIU Xiaoyu, YANG Wencai, CHEN Zhaoxi, QU Chen, YU Changqing. Attributes and evolution of the eastern massif in the Qinghai-Tibetan Plateau[J]. Earth Science Frontiers, 2023, 30(3): 233-241.

Figures/Tables 6

Fig.1 (a) Change of P-wave velocity of mantle with temperature, and (b) comparison of the temperature of the lithosphere and melting temperature of shallow crust-mantle at different depths. Modified after [16].

Fig.2 (a) Locations of the selected seismic stations (red triangles) and earthquake (intensity > MS 3) epicenters (green circles), and (b) raypath coverage map

Fig.3 Results of checkboard resolution test at different depths for P-wave tomography (a) and map view of P-wave velocity perturbations at different depths (b-d)

Fig.4 Distribution of main mountain ranges compared to lithospheric-thickness distribution in the Qinghai-Tibetan Plateau. Lines AB and CD mark boundaries of the eastern massif.

Fig.5 (a) Distribution of resistivity 100 km underground in and (b) surface Bouguer gravity anomaly map of the Qinghai-Tibetan Plateau. Lines AB and CD mark the boundaries of the eastern massif.

Fig.6 Evolution of the Southeast Asian plate restored from paleomagnetic data (80-10 Ma). Arrows mark the movement direction of the plate; letter “E” marks the location of the eastern Qinghai-Tibetan massif, with the flanking black lines marking the boundaries of the massif. Modified after [31].

References 31

[1]	杨文采, 侯遵泽, 于常青. 青藏高原地壳的三维密度结构和物质运动[J]. 地球物理学报, 2015, 58(11): 4223-4234.
[2]	杨文采, 孙艳云, 于常青. 青藏高原地壳密度变形带及构造分区[J]. 地球物理学报, 2015, 58(11): 4115-4128.
[3]	杨文采, 侯遵泽, 徐义贤, 等. 青藏高原下地壳热变形和管道流研究[J]. 地质论评, 2017, 63(5): 1141-1152.
[4]	杨文采, 瞿辰, 任浩然, 等. 青藏高原地壳地震纵波速度的层析成像[J]. 地质论评, 2019, 65(1): 2-14.
[5]	杨文采, 江金生, 瞿辰, 等. 西藏新生代裂谷系成因的探讨[J]. 地质论评, 2019, 65(2): 267-279.
[6]	杨文采, 瞿辰, 任浩然, 等. 青藏高原软流圈与特提斯洋板块俯冲[J]. 地质论评, 2019, 65(3): 521-532.
[7]	杨文采, 曾祥芝. 认知地球物质运动的大陆动力学方法[J]. 地质论评, 2020, 66(1): 1-12.
[8]	杨文采, 金胜, 张罗磊, 等. 青藏高原岩石圈三维电性结构[J]. 地球物理学报, 2020, 63(3): 817-827.
[9]	杨文采. 浅地幔系统的组成和属性相态[J]. 地质论评, 2020, 66(2): 263-275.
[10]	杨文采. 浅地幔系统的动力学作用[J]. 地质论评, 2020, 66(3): 521-532.
[11]	瞿辰, 刘晓宇, 于常青, 等. 青藏高原S波和泊松比的层析成像[J]. 地球物理学报, 2020, 63(10): 3640-3652.
[12]	杨文采, 刘晓宇, 陈召曦, 等. 从高分辨率地震层析成像看青藏高原软流圈的物质运动[J]. 地球科学, 2022, 47(10): 3491-3500.
[13]	JAMESD E. Encyclopedia of solid earth geophysics[M]. New York: Van Nostrand Reinhold Company, 1989.
[14]	JOLIVET L, HATAF H C. Geodynamics[M]. Lisse: August Aimé Balkema Publisher, 2001.
[15]	SHINEVAR W J, BEHN M D, HIRTH G, et al. Inferring crustal viscosity from seismic velocity: application to the lower crust of Southern California[J]. Earth and Planetary Science Letters, 2018, 494(1): 83-91. DOI URL
[16]	GARY M, TAPAN M, JACK D. The rock physics handbook (third revised edition)[M]. Cambridge: Cambridge University Press, 2020.
[17]	杨文采. 地球物理反演和地震层析成像[M]. 北京: 地质出版社, 1989.
[18]	HUANG L J, YANG W C. Inversion of the acoustic wave equation by inverse scattering[J]. Chinese Journal of Geophysics, 1991, 34(2): 331-341.
[19]	杨文采, 杜剑渊. 层析成像新算法及其在工程检测上的应用[J]. 地球物理学报, 1994, 37(2): 239-244.
[20]	YANGW C. Reflection seismology:theory, data processing, and interpretation[M]. Amsterdam: Elsevier, 2014.
[21]	瞿辰, 杨文采, 于常青. 塔里木盆地地震波速扰动及泊松比成像[J]. 地学前缘, 2013, 20(5): 196-206.
[22]	MO X X, ZHAO Z D, DENG J F, et al. Petrology and geochemistry of post-collisional volcanic rocks from the Tibetan plateau: implications for lithosphere heterogeneity and collision-induced asthenospheric mantle flow[J]. Geological Society of America, Special Paper, 2006, 409: 508-530.
[23]	李四光, 孙殿卿, 吴磊伯, 等. 旋卷和一般扭动构造及地质构造体系复合问题: 第2辑[M]. 北京: 科学出版社, 1958.
[24]	HOUSEMAN G, ENGLAND P. Crustal thickening versus lateral expulsion in the Indian-Asian continental collision[J]. Journal of Geophysical Research, Part B: Solid Earth, 1993, 98: 12233-12249.
[25]	WITTLINGER G, MASSON F, POUPINET G, et al. Seismic tomography of northern Tibet and Kunlun: evidence for crustal blocks and mantle velocity contrasts[J]. Earth and Planetary Science Letters, 1996, 139: 263-279. DOI URL
[26]	CLARK M K, ROYDEN L H. Topographic ooze: building the eastern margin of Tibet by lower crustal flow[J]. Geology, 2000, 28(8): 703-706. DOI URL
[27]	LI C, VAN DER HILST R, MELTZER A S, et al. Subduction of the Indian lithosphere beneath the Tibetan Plateau and Burma[J]. Earth and Planetary Science Letters, 2008, 274: 157-168. DOI URL
[28]	许志琴, 杨经绥, 李海兵, 等. 印度-亚洲碰撞大地构造[J]. 地质学报, 2011, 85(1): 1-33.
[29]	胥颐, 刘劲松, 黄忠贤, 等. 青藏高原上地幔速度结构及其动力学性质[J]. 地球物理学报, 2014, 57(12): 4085-4096.
[30]	CHENM, NIU F L, LIU Q Y, et al. Multiparameter adjoint tomography of the crust and upper mantle beneath East Asia: 1. Model construction and comparisons[J]. Journal of Geophysical Research: Solid Earth, 2015, 120(3): 1762-1786. DOI URL
[31]	HALL R. Plate tectonic evolution of SE Asia and the SW Pacific[J]. Tectonophysics, 2012, 570/571: 1-41. DOI URL