青藏高原东北缘壳幔过渡带研究  

STUDY OF CRUST-MANTLE TRANSITIONAL ZONE ALONG THE NORTHEAST MARGIN OF QINGHAI-XIZANG PLATEAU

作　　者：赖晓玲[1] 张先康[1] 方盛明[1] 

机构地区：[1]中国地震局地球物理勘探中心,中国郑州450002

出　　处：《地震学报》2004年第2期132-139,共8页Acta Seismologica Sinica

基　　金：地震科学联合基金 ( 10 2 0 2 5和 10 4 0 2 7)资助

摘　　要：利用穿过青藏高原东北缘的两条地震测深剖面提供的PMP波形资料 ,研究了该区不同构造单元壳幔过渡带的复杂性、频谱特征和速度模型 .结果表明 ,鄂尔多斯盆地和陵中盆地Moho具有稳定的构造特征 ,壳幔耦合为简单的一级间断面 ;海原地震区和巴颜喀拉地块与柴达木地块结合带莫霍面具有明显的活动迹象 ,壳幔耦合为复杂的高、低速相间的多层壳幔过渡带 ,总厚度达到 2 0多千米 .不同构造单元的莫霍面差异性反映了研究区壳幔耦合层的非均匀特征 ;海原地震区和玛沁断裂壳幔过渡带的细结构差异 ,则反映了两个陆This study deals with complexity, frequency spectrum and velocity model of the crust mantle transitional zone in different tectonic units along the northeast margin of Qinghai Xizang plateau, based on P M P waveform data from two deep seismic sounding profiles passing through the area. It reveals that Moho has stable tectonic features in Ordos and Lingzhong basins, where crust and mantle are coupled as first order discontinuity. Moho shows obvious signs of activity in Haiyuan seismic region and in the contact zone between Bayanhar block and Qaidam block. Crust and mantle in these two areas are coupled as complicated crust mantle transitional zone consisting of multiple laminae with alternate high and low velocities, totaling 20 km in thickness. The difference between Moho of different tectonic units reflects heterogeneity of the coupled crust mantle zone; the difference between fine structures of Haiyuan seismic region and Maqin fault zone reflects different deep material composition of the two continent continent collision zones and the interaction between blocks.

关 键 词：青藏高原 壳幔过渡带 构造单元 海原地震区 玛沁断裂带 

分 类 号：P315.2[天文地球—地震学]