摘要
通过1991—2001年期间在青藏高原东部及周边地区的GPS测量,获得该地区不同参考框架下的地壳运动速度场,其测量的速度精度高于2mm/yr。印度板块与华北地块之间的地壳形变分为喜马拉雅及高原南部、高原中部(拉萨—格尔木)和高原北部(格尔木—金塔)三部分,它们分别吸收了印度板块与欧亚板块汇聚速率的43%、24%和32%。在欧亚框架下和相对于成都,印度板块和华南地块之间存在着以东喜马拉雅构造结为轴心的顺时针巨型涡旋构造———滇藏涡旋构造,运动速度分别为26～6mm/yr和24～7mm/yr,总体上从北东方向转变为南东和南西方向,有别于青藏高原中部的北东方向。滇藏涡旋和东喜马拉雅构造结的形成与南迦巴瓦 阿萨姆"犄角"的楔入作用有关。
The velocity fields of the crustal motion within the Eurasia framework were measured with a precision of higher than 2 mm/yr on the basis of the Global Positioning System (GPS) measurements from 1991 to 2001 on the eastern Tibet Plateau and its adjacent areas in western China. The crustal deformation between the Indian and North China Plates is manifested in the following three parts: the Himalayas and southern part of the Plateau, central part of the Plateau (Lhasa to Golmud), and northern part of the Plateau (Golmud to Jinta), where 43 per cent, 24 per cent, and 32 per cent of the plate convergence rates are absorbed between the Indian and Eurasian plates. There exist the giant clockwisely rotated whirl structures, i.e. the (Yunnan-Tibet) whirl structures, which take the eastern Himalayan syntaxis between the Indian and South China plates as an axis. The velocities of motion for the (Yunnan-Tibet) whirl structures range between (26 to 6 mm/yr) and (24 to 7 mm/yr). Unlike the NE direction of the rotation in the central part of the Tibet Plateau, the (Yunnan-Tibet) whirl structures on the eastern Tibet Plateau, relative to Chengdu in Sichuan, are generally rotated from the northeast to the southeast and southwest. A direct genetic affiliation of the (Yunnan-Tibet) whirl structures and the eastern Himalayan syntaxis to the wedging of the (Namjagbarwa-Asarm) 'horn' was postulated.
出处
《沉积与特提斯地质》
CAS
CSCD
2003年第4期1-8,共8页
Sedimentary Geology and Tethyan Geology
基金
地矿部"八五"深部项目(85 06 214)
国土资源部"九五"重大基础项目"青藏高原东部现代地壳运动GPS监测"(9501101)
美国自然基金(EAR8904096
EAR9614670和INT9005305)。
关键词
青藏高原东部
速度场
欧亚参考框架
地壳形变
eastern Tibet Plateau
velocity field
Eurasia framework
crustal deformation
