1 Lithosphere Research Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 2 Earthprobe and Geodynamics Open Laboratory, Chinese Academy of Geological Sciences, Beijing 100037, China
Integrated geophysical evidence for a new style of continent-continent collision beneath the western Kunlun in the northwestern China
1 Lithosphere Research Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China 2 Earthprobe and Geodynamics Open Laboratory, Chinese Academy of Geological Sciences, Beijing 100037, China
摘要Along the western Kunlun-Tarim-Tianshan geoscience transect in the northwestern China, an integrated geophysical investigation was carried out. Owing to the abominable natural conditions there, the sounding profile could not cross the whole transect, consequentially, a variety of velocity structures in the transverse and vertical orientations beneath the whole transect were not obtained, such as the case within the western Kunlun orogenic belt. To supply a gap of deep seismic soundings within the western Kunlun orogenic belt, we used the Bouguer gravity anomaly data and the relationship between the compressive wave and the density to obtain the density structure of the crust beneath the western Kunlun and the southern Tarim basin by a forward fitting of gravity anomalies within the two-dimensional polygonal model of uniform medium. The crust of the Tarim basin with a rigid basement was like an asymmetrical arc, whose surface feature was the Bachu uplift in the middle of the Tarim basin. Beneath the conjoint area between the Tarim basin and the western Kunlun belt, there was a V-shape structure located just up to the top of the uplifted Moho. The multi-seismological structures jointly revealed that the face-to-face continent-continent collision beneath the western Kunlun is a new structural style within the continent-continent collision zone, which is a real model proved by the numerical modeling.
Abstract:Along the western Kunlun-Tarim-Tianshan geoscience transect in the northwestern China, an integrated geophysical investigation was carried out. Owing to the abominable natural conditions there, the sounding profile could not cross the whole transect, consequentially, a variety of velocity structures in the transverse and vertical orientations beneath the whole transect were not obtained, such as the case within the western Kunlun orogenic belt. To supply a gap of deep seismic soundings within the western Kunlun orogenic belt, we used the Bouguer gravity anomaly data and the relationship between the compressive wave and the density to obtain the density structure of the crust beneath the western Kunlun and the southern Tarim basin by a forward fitting of gravity anomalies within the two-dimensional polygonal model of uniform medium. The crust of the Tarim basin with a rigid basement was like an asymmetrical arc, whose surface feature was the Bachu uplift in the middle of the Tarim basin. Beneath the conjoint area between the Tarim basin and the western Kunlun belt, there was a V-shape structure located just up to the top of the uplifted Moho. The multi-seismological structures jointly revealed that the face-to-face continent-continent collision beneath the western Kunlun is a new structural style within the continent-continent collision zone, which is a real model proved by the numerical modeling.
基金资助:the National Natural Science Foundation of China (40404011, 40774051, 49734230), the basic outlay of scientific research work from Ministry of Science and Technology of the People’s Republic of China in 2007 and 2008 (J0707, J0803), Sino-American collaboration project from Ministry of Science and Technology of the People’s Republic of China (2006DFA21340), China National Probing Project (SinoProbe-02), and Open Fund of Geo-detection Laboratory, Ministry of Education of China, and China University of Geosciences (No. GDL0602)
通讯作者:
Rizheng He
E-mail: herizheng@cags.ac.cn
引用本文:
Rizheng He, Rui Gao, Qiusheng Li, Ye Guan. Integrated geophysical evidence for a new style of continent-continent collision beneath the western Kunlun in the northwestern China[J]. 《地震学报》英文版, 2009, 22(4): 379-387.
Rizheng He, Rui Gao, Qiusheng Li, Ye Guan. Integrated geophysical evidence for a new style of continent-continent collision beneath the western Kunlun in the northwestern China. Earthquake Science, 2009, 22(4): 379-387.