Systematic variations in seismic velocity and reflection in the crust of Cathaysia: New constraints on intraplate orogeny in the South China continent

被引:66
作者
Zhang, Zhongjie [1 ]
Xu, Tao [1 ]
Zhao, Bing [1 ]
Badal, Jose [2 ]
机构
[1] Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China
[2] Univ Zaragoza, E-50009 Zaragoza, Spain
关键词
Wide-angle seismic data; Crustal velocity; Frequency filtering; Migration and stacking; Lithospheric extension; Yangtze block; Cathaysia block; ZIRCON U-PB; SOUTHEASTERN CHINA; YANGTZE BLOCK; TECTONIC EVOLUTION; NORTHERN MARGIN; ND; BENEATH; MANTLE; COLLISION; ROCKS;
D O I
10.1016/j.gr.2012.05.018
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
The South China continent has a Mesozoic intraplate orogeny in its interior and an oceanward younging in postorogenic magmatic activity. In order to determine the constraints afforded by deep structure on the formation of these characteristics, we reevaluate the distribution of crustal velocities and wide-angle seismic reflections in a 400 km-long wide-angle seismic profile between Lianxian, near Hunan Province, and Gangkou Island, near Guangzhou City, South China. The results demonstrate that to the east of the Chenzhou-Linwu Fault (CLF) (the southern segment of the Jiangshan-Shaoxing Fault), the thickness and average P-wave velocity both of the sedimentary layer and the crystalline basement display abrupt lateral variations, in contrast to layering to the west of the fault. This suggests that the deformation is well developed in the whole of the crust beneath the Cathaysia block, in agreement with seismic evidence on the eastwards migration of the orogeny and the development of a vast magmatic province. Further evidence of this phenomenon is provided in the systematic increases in seismic reflection strength from the Moho eastwards away from the boundary of the CLF, as revealed by multi-filtered (with band-pass frequency range of 1-4, 1-8, 1-12 and 1-16 Hz) wide-angle seismic images through pre-stack migration in the depth domain, and in the P-wave velocity model obtained by travel time fitting. The CLF itself penetrates with a dip angle of about 22 degrees to the bottom of the middle part of the crust, and then penetrates with a dip angle of less than 17 degrees in the lower crust. The systematic variation in seismic velocity, reflection strength and discrepancy of extensional factors between the crust and the lithosphere, are interpreted to be the seismic signature of the magmatic activity in the interest area, most likely caused by the intrusion of magma into the deep crust by lithospheric extension or mantle extrusion. (C) 2012 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.
引用
收藏
页码:902 / 917
页数:16
相关论文
共 105 条
[1]   INVERSION OF FIELD DATA IN FAULT TECTONICS TO OBTAIN THE REGIONAL STRESS .3. A NEW RAPID DIRECT INVERSION METHOD BY ANALYTICAL MEANS [J].
ANGELIER, J .
GEOPHYSICAL JOURNAL INTERNATIONAL, 1990, 103 (02) :363-376
[2]  
Bally A.W., 1966, Bulletin of Canadian Petroleum Geology, V14, P337
[3]   The building of south China: Collision of Yangzi and Cathaysia blocks, problems and tentative answers [J].
Charvet, J ;
Shu, LS ;
Shi, YS ;
Guo, LZ ;
Faure, M .
JOURNAL OF SOUTHEAST ASIAN EARTH SCIENCES, 1996, 13 (3-5) :223-235
[4]   Two episodes of the Indosinian thermal event on the South China Block: Constraints from LA-ICPMS U-Pb zircon and electron microprobe monazite ages of the Darongshan S-type granitic suite [J].
Chen, Cheng-Hong ;
Hsieh, Pei-Shan ;
Lee, Chi-Yu ;
Zhou, Han-Wen .
GONDWANA RESEARCH, 2011, 19 (04) :1008-1023
[5]   Crustal evolution of southeastern China: Nd and Sr isotopic evidence [J].
Chen, JF ;
Jahn, BM .
TECTONOPHYSICS, 1998, 284 (1-2) :101-133
[6]   SEISMIC VELOCITY STRUCTURE AND COMPOSITION OF THE CONTINENTAL-CRUST - A GLOBAL VIEW [J].
CHRISTENSEN, NI ;
MOONEY, WD .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1995, 100 (B6) :9761-9788
[7]  
Davis M, 2004, MARG THEOR EXP EARTH, P92
[8]   Crustal structure beneath South China revealed by deep seismic soundings and its dynamics implications [J].
Deng Yang-Fan ;
Li Shou-Lin ;
Fan Wei-Ming ;
Liu Jia .
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2011, 54 (10) :2560-2574
[9]   Lower crustal extension across the Northern Carnarvon basin, Australia: Evidence for an eastward dipping detachment [J].
Driscoll, NW ;
Karner, GD .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1998, 103 (B3) :4975-4991
[10]   Tracing the position of the South China block in Gondwana: U-Pb ages and Hf isotopes of Devonian detrital zircons [J].
Duan, Liang ;
Meng, Qing-Ren ;
Zhang, Cheng-Li ;
Liu, Xiao-Ming .
GONDWANA RESEARCH, 2011, 19 (01) :141-149