The Feature of Tectonics in the Tibetan Plateau from New Regional Gravity Signals
详细信息
- 责任者：Zhang Yan (State Key Laboratory of Continental Dynamics ; Department of Geology ; Northwest University ; Xi’an 710069 ; China) ; Cheng Shunyou
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(4)
- 关键词：深部构造 ; deep-seated structure ; 重力异常 ; gravity anomaly ; 青藏高原 ; Qinghai-Tibetan Plateau
- 页码：p.1369-1380
- 图表：illus., 47 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
As of 2007,1:1000000 regional gravity investigations have been completed in Qinghai-Tibet Plateau.We obtain useful information by analyzing the gravity anomaly in different depth levels of the plateau,based on various data processing results to build a structure model.Our results show that the gravity feature in Tibet is unique,with diverse contact relations with adjacent blocks.The gravity minimum and maximum can be related to the arc-basin and magmatic belts,and suture zones where amphibolites were found.This feature above shows that Tibet is pieced together with many sutures.The gravity field is divided into two parts of the southern and northern within the plateau in different depth by the Bouguer gravity anomaly of Bangong-Nujiang suture zone,which is the most important gravity maximum anomalies over 1000 km long.This information provides evidence that Bangong-Nujiang suture is the northern boundary of Gondwana.Local gravity anomaly exhibits similar feature of geotectonic division.Majority of structural trend is EW-striking from south to north,whereas in the eastern plateau it strikes NW-SN.There are two gravity anomaly lines near the 85°E and 92°E longitude.It suggests that the deep structure of plateau is divided into three parts from east to west,in contrast to the EW-striking surficial structure.