Teleseismic shear wave splitting and lithospheric beneath and across the Altyn Tagh fault.

被引:54
作者
Herquel, G
Tapponnier, P
Wittlinger, G
Mei, J
Danian, S
机构
[1] Ecole & Observ Sci Terre, F-67084 Strasbourg, France
[2] IPG, Lab Tecton, F-75205 Paris, France
[3] Chinese Acad Geol Sci, Inst Mineral Deposits, Beijing 100037, Peoples R China
关键词
D O I
10.1029/1999GL005387
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Sixteen 3-component, 5-sec stations along a profile crossing the Altyn Tagh fault (ATF) at similar to 90 degrees E were used to measure shear wave splitting beneath Tibet's northern edge. Splitting delay times (delta t) of 0.3 to 1.3 sec show a marked increase in a narrow zone centered on the fault, implying anisotropy in the lithospheric mantle. Fast Polarization Directions (FPD) (phi) swing counterclockwise, from a mean azimuth of similar to 110 degrees E in the Qaidam basin south of the fault, to a mean azimuth of similar to 60 degrees E in the Altyn mountains. This swing occurs in less than 40 km. Both the delta t increase and FPD swing are consistent with ductile sinistral shear along the 40 km-wide, low P-wave velocity anomaly (-6-8%) imaged to a depth of similar to 140 km beneath the fault by teleseismic tomography. This confirms that the ATF guides the northeastwards extrusion of the Tibet-Qaidam's lithosphere relative to the Tarim's.
引用
收藏
页码:3225 / 3228
页数:4
相关论文
共 22 条
[1]   ANISOTROPY BENEATH 9 STATIONS OF THE GEOSCOPE BROAD-BAND NETWORK AS DEDUCED FROM SHEAR-WAVE SPLITTING [J].
ANSEL, V ;
NATAF, HC .
GEOPHYSICAL RESEARCH LETTERS, 1989, 16 (05) :409-412
[2]   A QUANTITATIVE-EVALUATION OF THE CONTRIBUTION OF CRUSTAL ROCKS TO THE SHEAR-WAVE SPLITTING OF TELESEISMIC SKS WAVES [J].
BARRUOL, G ;
MAINPRICE, D .
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 1993, 78 (3-4) :281-300
[3]   A study of azimuthal P residuals and shear-wave splitting across the Kunlun range (Northern Tibetan plateau) [J].
Guilbert, J ;
Poupinet, G ;
Mei, J .
PHYSICS OF THE EARTH AND PLANETARY INTERIORS, 1996, 95 (3-4) :167-174
[4]   ANISOTROPY AND CRUSTAL THICKNESS OF NORTHERN-TIBET - NEW CONSTRAINTS FOR TECTONIC MODELING [J].
HERQUEL, G ;
WITTLINGER, G ;
GUILBERT, J .
GEOPHYSICAL RESEARCH LETTERS, 1995, 22 (14) :1925-1928
[5]   SEISMIC ANISOTROPY AS AN INDICATOR OF MANTLE FLOW BENEATH THE HIMALAYAS AND TIBET [J].
HIRN, A ;
JIANG, M ;
SAPIN, M ;
DIAZ, J ;
NERCESSIAN, A ;
LU, QT ;
LEPINE, JC ;
SHI, DH ;
SACHPAZI, M ;
PANDEY, MR ;
MA, K ;
GALLART, J .
NATURE, 1995, 375 (6532) :571-574
[6]   FINITE STRAIN CALCULATIONS OF CONTINENTAL DEFORMATION .1. METHOD AND GENERAL RESULTS FOR CONVERGENT ZONES [J].
HOUSEMAN, G ;
ENGLAND, P .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1986, 91 (B3) :3651-3663
[7]   Seismic anisotropy beneath Tibet: Evidence for eastward extrusion of the Tibetan lithosphere? [J].
Lave, J ;
Avouac, JP ;
Lacassin, R ;
Tapponnier, P ;
Montagner, JP .
EARTH AND PLANETARY SCIENCE LETTERS, 1996, 140 (1-4) :83-96
[8]   The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina [J].
Leloup, PH ;
Lacassin, R ;
Tapponnier, P ;
Scharer, U ;
Zhong, DL ;
Liu, XH ;
Zhang, LS ;
Ji, SC ;
Trinh, PT .
TECTONOPHYSICS, 1995, 251 (1-4) :3-&
[9]   Shear heating in continental strike-slip shear zones: model and field examples [J].
Leloup, PH ;
Ricard, Y ;
Battaglia, J ;
Lacassin, R .
GEOPHYSICAL JOURNAL INTERNATIONAL, 1999, 136 (01) :19-40
[10]  
MAKAYEVA LI, 1992, NATURE, V358, P144