摘要
利用卫星重力异常研究中国西部岩石圈构造,发现中国西部壳内存在规律、清晰的平行线状排列盆山构造。自北而南是:额尔齐斯盆地带、北准噶尔隆升带、天山北盆地带(或天北盆地带)、天山隆升带、淖毛湖—乌力吉盆地带、天山南盆地带(或天南盆地带)、库鲁克塔克—北山隆升带、阿尔金山—祁连山北盆地带(或塔南盆地带)、西昆仑—阿尔金—祁连山隆升带以及柴达木盆地带和藏南盆地带。壳内盆地带主要形成于印支—燕山期强烈的挤压褶皱带内。喜马拉雅期,在印度板块自南西向北东的俯冲作用下,使婆罗科努山—察布查尔山—阿拉沟山—额尔宾山—霍拉山等山系横向隆升,和天山山脉一起,将新疆地区分割成伊宁盆地、准噶尔盆地、吐哈盆地和塔里木盆地,形成当今新疆地貌。研究表明,上述横向隆升山脉和其他北西—南东向新构造,在岩石圈地幔中均有相应的卫星重力异常,推测新构造运动的动力来自岩石圈地幔。对青藏高原的研究表明,青藏高原以雅鲁藏布江断裂、班公湖—怒江断裂、澜沧江和金沙江断裂等一系列相互平行的断层和其夹持的条形地块为特征,表层构造与壳内构造不符。这些条形构造和青藏高原地壳向东南的逃逸构造仅发生在上地壳。研究还表明印度板块俯冲到地幔仅发生在西藏西南部。在川西—藏东存在南北向的稳定地块。
The 3D lithospheric structure of western China studied by using satellite gravity anomalies revealed that in the crust of western China there exist regular, distinct, parallel, linear basin-range structures. From north to south, there are: the Ertix basin belt, North Junggar uplift belt, North Tianshan basin belt, Tianshan uplift belt, Naomaohu -Olji basin belt, South Tianshan basin belt, Kuruktag- Beishan uplift belt, Altyn Tagh(Altun)-North Qilian belt (or South Tarim basin belt) and West Kunlun-Altyn Tagh-Qilian uplift belt, as well as the Qaidam basin belt and southern Tibet basin belt. These crustal basin belts formed by strong basal compression folding in the Indosinian-Yanshanian period. In the Himalayan period, northeast-directed subduction of the Indian plate resulted in uplift of the Borohoro-Qapqal -Ala Gou-Erben-Horo mountains, and they together with the Tianshan Mountains divide Xinjiang into the Tarim basin, Junggar basin, Tuha basin and Yining basin, forming the present-day geomorphology of Xinjiang. These NW-SE mountains and other NW-SE neotectonics have their corresponding satellite gravity anomalies in the lid of the lithosphere. Thus it is inferred that the dynamic force of the neotectonic movement was derived from the lithospheric mantle. In Tibet, the idea that the Tibetan Plateau is regarded as the superficial structure formed by a number of parallel faults such as the Yalung Zangbo fault, Bangong Co-Nujiang fault, Lanchang River fault and Jinsha River fault and the elongated blocks sandwiched therein does not conform to the crustal structure at ~15 to 18 km depth. This kind of elongated block structure and the southeast-directed escape structure only occur in the upper crust. Study also indicates that subduction of the Indian plate to the mantle only occurs in southwestern Tibet. In western Sichuan-eastern Tibet there exits a stable block which interrupts subduction of Indian plate beneath Tibet. The study provides the following enlightenment on petroleum prospecting: (1) petroleum prospecting in western China should not be restricted in Cenozoic basins; (2) in the study of the tectonic setting of basins in western China one should consider the structural control at depths; and (3) basic research may play an important role in petroleum prospecting and furnish clues leading to finding Paleozoic and Mesozoic oil/gas fields, and the research results may be used for reference in work arrangement, and especially we should carry out a systematic investigation and study of the whole deep aspects of the North Tianshan basin belt, South Tianshan basin belt, South Tarim basin belt, Qaidam basin belt and North Tibet basin belt and their control on the surface structures.
出处
《中国地质》
CAS
CSCD
2005年第1期1-12,共12页
Geology in China
基金
国土资源部专项计划项目(200010103)资助。
