龙门山断裂带及其邻区电性结构特征

doi:10.11720/wtyht.2019.1105

Abstract
Figure/Table
References
Related Citation (6)

Download: PDF (10176 KB) HTML (0 KB)
Export: BibTeX | EndNote (RIS)

Abstract

Longmen fault zone is one of the most famous orogenic belts and seismic zones in the continental crust of China. In order to study the deep structure of Longmen thrust nappe belt and its relationship with the eastward escaping of material in the Tibetan Plateau, the authors completed four magnetotellurics profiles across the West Qinling orogenic belt, Songpan-Garze fold belt and the Sichuan basin, which included 80 broad-band magnetotellurics stations and 16 long-period stations. The electrical model diagram was obtained through two-dimensional and three-dimensional inversion. The model indicates that the Longmen Mountain fault zone is basically coincided with the electrical gradient zone in the depth less than 30 km. It means that the Longmen fault zone is a fault zone which is deep in the middle of the crust. Above the depth of 20 km, the distribution characteristics of the electrical structure in Songpan-Garze fold belt are complex and of low-conductivity, which is related to the complex surface structure. Below 20 km, the low conductivity is similar to that of the Longmen fault zone. It is inferred that high resistivity may be a reflection of the basement of the Sichuan basin, indicating that the Songpan-Garze fold belt pushed over Sichuan basin bounded by Longmen fault zone. It is concluded that the material migration under the Tibetan Plateau happened under the Songpan-Garze fold belt. The material escaped northeastward from Lixian to Dangchang, at the depth of 18km to 30km with the partial-melting.

Key words： magnetotellurics Longmen fault zone material migration under the Tibetan Plateau electrical structure characteristics of crust and mantle deep dynamic process

Received: 13 March 2018 Published: 20 February 2019

P631

	Service

	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	Dai-Li XU
	Bao-Shan TANG
	Wen-Bo WEI

Cite this article:

Dai-Li XU,Bao-Shan TANG,Wen-Bo WEI. Electrical structure characteristics of Longmen fault zone and its adjacent areas[J]. Geophysical and Geochemical Exploration, 2019, 43(1): 17-27.

URL:

https://www.wutanyuhuatan.com/EN/10.11720/wtyht.2019.1105 OR https://www.wutanyuhuatan.com/EN/Y2019/V43/I1/17

The position indication of magnetotelluric sounding data in the study area
The red dot is the wide-band magnetotelluric sounding point, and the blue dot is the long-period magnetotelluric sounding point

Broadband and long period magnetotelluric sounding instrument

Apparent resistivity and phase curves of different blocks in the study area

Schematic diagram of phase tensor

The analysis result of phase tensor in study area

Rose diagram of G-B decomposition in study area

The comparison diagram of apparent resistivity and impedance phase of TM polarization modes measured on different profiles and calculated by two-dimensional forward

The 2-D inversion electrical structure model of different longtitude

The variation of rms value with the change of iteration times during the 3-D inversion process

The 3-D inversion slice diagram of different depth in study area

The moving direction of low resistivity body C1

Statistics of thermal structure parameters of lithosphere in the study area

Distribution of partial melting layer in crust of study area

[1]	刘树根, 李智武, 曹俊兴 , 等. 龙门山陆内复合造山带的四维结构构造特征[J]. 地质科学, 2009,44(4):1151-1180.
[1]	Liu S G, Li Z W, Cao J X , et al. 4-D textural and structural characteristics of Longm en intracontinental composite orogenic belt,southwest China[J]. Chinese Journal of Geology, 2009,44(4):1151-1180.
[2]	Burchfiel B C, Quidong D, Molnar P , et al. Intracrustal detachment within zones of continental deformation[J]. Geology, 1989,17(8):748-752.
[3]	Royden L H, Burchfiel B C, King R W , et al. Surface deformation and lower crustal flow in eastern tibet[J]. Science, 1997,276(5313):788-790.
[4]	Tapponnier P, Xu Z Q, Roger F , et al. Oblique stepwise rise and growth of the tibet plateau[J]. Science, 2001,294(5547):1671-1677.
[5]	Burchfiel B C, Royden L H, Hilst R D V D , et al . A geological and geophysical context for the Wenchuan earthquake of 12 May 2008, Sichuan, People’s Republic of China[J]. Gsa Today, 2008,18(18):4-11.
[6]	张振宇, 王绪本, 方慧 . 龙门山构造带中段大地电磁测深研究[J]. 物探与化探, 2012,26(3):377-381.
[6]	Zhang Z Y, Wang X B, Fang H . A study of magnetotelluric sounding in the middle segment of the Longmensham structural belt[J]. Geophysical and Geochemical Exploration, 2012,26(3):377-381.
[7]	Zhao G, Unsworth M J, Zhan Y , et al. Crustal structure and rheology of the Longmenshan and Wenchuan Mw 7.9 earthquake epicentral area from magnetotelluric data[J]. Geology, 2012,40(12):1139-1142.
[8]	王绪本, 朱迎堂, 赵锡奎 , 等. 青藏高原东缘龙门山逆冲构造深部电性结构特征[J]. 地球物理学报, 2009,52(2):564-571.
[8]	Wang X B, Zhu Y T, Zhao X K , et al. Deep conductivity characteristics of the Longmen Shan, eastern Qinghai-Tibet plateau[J]. Chines Journal of Geophysics, 2009,52(2):564-571.
[9]	楼海, 王椿镛, 姚志祥 , 等. 龙门山断裂带深部构造和物性分布的分段特征[J]. 地学前缘, 2010,17(5):128-141.
[9]	Lou H, Wang C Y, Yao Z X , et al. Subsection feature of the deep structure and material properties of Longmenshan fault zone[J]. Earth Science Frontiers, 2010,17(5):128-141.
[10]	Gamble T D, Goubau W M, Clarke J . Magnetotellurics with a remote magnetic reference[J]. Geophysics, 1979,44(1):53-68.
[11]	Egbert G D, Booker J R . Robust estimation of geomagnetic transfer functions[J]. Geophysical Journal International, 1986,87(1):173-194.
[12]	金胜, 魏文博, 汪硕 , 等. 青藏高原地壳高导层的成因及动力学意义探讨——大地电磁测深提供的证据[J]. 地球物理学报, 2010,53(10):2376-2385.
[12]	Jin S, Wei W B, Wang S , et al. Discussion of the foemation and dynamic signification of the high conductive layer in Tibetan crust[J]. Chines Journal of Geophysics, 2010,53(10):2376-2385.
[13]	魏文博, 金胜, 叶高峰 , 等. 藏北高原地壳及上地幔导电性结构——超宽频带大地电磁测深研究结果[J]. 地球物理学报, 2006,49(4):1215-1225.
[13]	Wei W B, Jin S, Ye G F , et al. Conductivity structure and rheological property of lithosphere in nouthern Tibet inferred from super-broadband magmetotulleric sounding[J]. Chines journal of geophysics, 2006,49(4):1215-1225.
[14]	魏文博, 金胜, 叶高峰 , 等. 藏南岩石圈导电性结构与流变性——超宽频带大地电磁测深研究结果[J]. 中国科学D辑:地球科学, 2009,39(11):1591-1606.
[14]	Wei W B, Jin S, Ye G F , et al. Conductivity structure and rheological property of lithosphere in southern Tibet inferred from super-broadband magmetotulleric sounding[J]. Sci China Ser D-Earth Sci, 2009,39(11):1591-1606.
[15]	魏文博, 陈乐寿, 谭捍东 , 等. 西藏中、南部壳内高导体与热结构特点——INDEPTH-MT提供的证据[J]. 现代地质, 1997,11(3):387-392.
[15]	Wei W B, Chen L S, Tan H D , et al. Features of thermal structure and highly conductive bodies in middle crust beneath central and southern Tibet: according to INDEPTH-MT results[J]. Journal of Graduate School, 1997,11(3):387-392.
[16]	魏文博 . 我国大地电磁测深新进展及瞻望[J]. 地球物理学进展, 2002,17(2):245-254.
[16]	Wei W B . New advance and prospect of magnetotelluric sounding (MT) in China[J]. Progress in Geophysics, 2002,17(2):245-254.
[17]	魏文博, 金胜, 叶高峰 , 等. 中国大陆岩石圈导电性结构研究——大陆电磁参数“标准网”实验(SinoProbe-01)[J]. 地质学报, 2010,84(6):788-800.
[17]	Wei W B, Jin S, Ye G F , et al. On the conductive structure of Chinese continental lithosphere-experiment on "standard monitoring network" of continental EM parameters[J]. Acta Geologica sinica, 2010,84(6):788-800.
[18]	Groom R W, Bailey R C . Decomposition of magnetotelluric impedance tensors in the presence of local three-Dimensional galvanic distortion[J]. Journal of Geophysical Research, 1989,94(B2):1913-1925.
[19]	McNeice G W, Jones A G . Multisite, multifrequency tensor decomposition of magnetotelluric data[J]. Geophysics, 2001,66(1):158-173.
[20]	Moorkamp M . Comment on ‘The magnetotelluric phase tensor’by T. Grant Caldwell, Hugh M. Bibby and Colin Brown[J]. Geophysical Journal International, 2007,171(2):565-566.
[21]	蔡军涛, 陈小斌 . 大地电磁资料精细处理和二维反演解释技术研究(二)——反演数据极化模式选择[J]. 地球物理学报, 2010,53(11):2703-2714.
[21]	Cai J T, Chen X B. Refined techniques for data processing and two一dimensional inversion in magnetotelluric Ⅱ: Which data polarization mode should be used in 2D inversion[J]. Chinese journal of Geophysics, 2010,53(11):2703-2714.
[22]	张乐天, 金胜, 魏文博 , 等. 青藏高原东缘及四川盆地的壳幔导电性结构研究[J]. 地球物理学报, 2012,55(12):4126-4137.
[22]	Zhang L T, Jin S, Wei W B , et al. Electrical structure of crust and upper mantle beneath the eastern margin of the Tibetan plateau and the Sichuan basin[J]. Chinese journal of Geophysics, 2012,55(12):4126-4137.
[23]	许志琴, 李化启, 侯立炜 , 等. 青藏高原东缘龙门锦屏造山带的崛起——大型拆离断层和挤出机制 [J]. 地质通报, 2007,26(10):1262-1276.
[23]	Xu Z Q, Li H Q, Hou L W , et al. Uplift of the Longmen-Jinping orogenic belt along the eastern margin of the Qinghai-Tibet plateau:Large-scale detachment faulting and extrusion mechanism[J]. Geological Bulletin of China, 2007,26(10):1262-1276.
[24]	许至琴, 卢一伦, 汤耀庆 , 等. 东秦岭复合山链的形成——变形、演化及板块动力学[M]. 北京: 中国环境科学出版社, 1988.
[24]	Xu Z Q, Lu Y L, Tang Y Q , et al. Formation, deformation, evolution and plate dynamics of the eastern Qinling composite mountain chain[M]. Beijing: China Environmental Science Press, 1988.
[25]	许志琴, 王勤, 曾令森 , 等. 高喜马拉雅的三维挤出模式[J]. 中国地质, 2013,40(3):671-680.
[25]	Xu Z Q, Wang Q, Zeng L S , et al. Three-dimensional extrusion model of the Great Himalaya slice[J]. Geology in China, 2013,40(3):671-680.
[26]	许志琴, 杨经绥, 李海兵 , 等. 中央造山带早古生代地体构架与高压/超高压变质带的形成[J]. 地质学报, 2006,80(12):1793-1806.
[26]	Xu Z Q, Yang J S, Li H B , et al. The early palaeozoic terrene framework and the formation of the high-pressure (HP) and ultra-high pressure (UHP) metamorphic belts at the central orogenic belt (COB)[J]. Acta Geologica Sinica, 2006,80(12):1793-1806.
[27]	许志琴, 杨经绥, 李海兵 , 等. 青藏高原与大陆动力学——地体拼合、碰撞造山及高原隆升的深部驱动力[J]. 中国地质, 2006,33(2):221-238.
[27]	Xu Z Q, Yang J S, Li H B , et al. The Qinghai-Tibet plateau and continental dynamics: A review on terrain tectonics, collisional orogenesis, and processes and mechanisms for the rise of the plateau[J]. Geology in China, 2006,33(2):221-238.
[28]	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.
[29]	孟小红, 石磊, 郭良辉 , 等. 青藏高原东北缘重力异常多尺度横向构造分析[J]. 地球物理学报, 2012,55(12):3933-3941.
[29]	Meng X H, Shi L, Guo L H , et al. Multi-scale analyses of transverse structures based on gravity anomalies in the northern margin of the Tibetan plateau[J]. Chinese journal of Geophysics, 2012,55(12):3933-3941.
[30]	喻学惠, 莫宣学, 赵志丹 , 等. 西秦岭新生代双峰式火山作用及南北构造带成因初探[J]. 岩石学报, 2011,27(7):2195-2202.
[30]	Yu X H, Mo X X, Zhao Z D , et al. Cenozoic bimodal volcanic rocks of the west Qinling: Implication for the genesis and nature of the rifting of north-south tectonic belt[J]. Acta Petrologica Sinica, 2011,27(7):2195-2202.
[31]	Bahr K . Geological noise in magnetotelluric data: A classification of distortion types[J]. Physics of the Earth & Planetary Interiors, 1991,66(1):24-38.
[32]	Cagniard L . Basic theory of the magneto-telluric method of geophysical prospecting[J]. Geophysics, 1953,18(3):605-635.
[33]	Caldwell T G, Bibby H M, Brown C . The magnetotelluric phase tensor[J]. Geophysical Journal International, 2004,158(2):457-469.
[34]	Dong H, Wei W, Ye G , et al. Three-dimensional electrical structure of the crust and upper mantle in Ordos Block and adjacent area: Evidence of regional lithospheric modification[J]. Geochemistry, Geophysics, Geosystems, 2014,15(6):2414-2425.
[35]	Ledo J . 2-D Versus 3-D Magnetotelluric data interpretation[J]. Surveys in Geophysics, 2005,26(5):511-543.
[36]	Parkinson W D . Directions of rapid geomagnetic fluctuations[J]. Geophysical Journal International, 1959,2(1):1-14.
[37]	Siripunvaraporn W, Egbert G . WSINV3DMT: Vertical magnetic field transfer function inversion and parallel implementation[J]. Physics of the Earth & Planetary Interiors, 2009,173(3):317-329.
[38]	Siripunvaraporn W, Egbert G, Lenbury Y , et al. Three-dimensional magnetotelluric inversion: Data-space method[J]. Physics of the Earth & Planetary Interiors, 2005,150(1):3-14.
[39]	Siripunvaraporn W, Egbert G, Uyeshima M . Interpretation of two-dimensional magnetotelluric profile data with three-dimensional inversion: synthetic examples[J]. Geophysical Journal International, 2005,160(3):804-814.
[40]	Swift C M . A magnetotelluric investigation of an electrical conductivity anomaly in the SW United States[J]. Dept. of Geology and Geophysics, 1967,156(20):201-210.
[41]	Tikhonov A . On determining electrical characteristics of the deep layers of the earth’s crust[J]. Sov, Math, Dokl, 1950,73(2):295-297.
[42]	Yuan Y, Hu S, Wang H , et al. Meso-Cenozoic tectonothermal evolution of Ordos basin, central China: Insights from newly acquired vitrinite reflectance data and a revision of existing paleothermal indicator data[J]. Journal of Geodynamics, 2007,44(1):33-46.
[43]	高锐, 马永生, 李秋生 , 等. 松潘地块与西秦岭造山带下地壳的性质和关系——深地震反射剖面的揭露[J]. 地质通报, 2006,25(12):1361-1367.
[43]	Gao R, Ma Y S, Li Q S , et al. Structur e of the lower crust beneath the Songpan block and west Qinling orogen and their relation as revealed by deep seismic reflection profiling[J]. Geological Bulletin of China, 2006,25(12):1361-1367.
[44]	高锐, 王海燕, 马永生 , 等. 松潘地块若尔盖盆地与西秦岭造山带岩石圈尺度的构造关系——深地震反射剖面探测成果[J]. 地球学报, 2006,27(5):411-418.
[44]	Gao R, Wang H Y, Ma Y S , et al. Tectonic relationships between the Zoige basin of the Song-Pan block and the west Qinling orogen at lithosphere scale: Results of deep seismic reflection profiling[J]. Acta Geoscientica Sinica, 2006,27(5):411-418.
[45]	任战利, 张盛, 高胜利 , 等. 鄂尔多斯断块构造热演化史及其成藏成矿意义[J]. 中国科学, 2007,37(1):23-32.
[45]	Ren Z L, Zhang S, Gao S L , et al. Tectonic and thermal evolution history of Ordos basin and Its significance for reservoir and mineralization[J]. Scientia Sinica, 2007,37(1):23-32.