东昆仑造山带中地壳存在古洋壳俯冲的深反射地震证据  

Ancient Oceanic Crustal Subduction of the East Kunlun Orogenic Belt:Evidence from Deep-Reflection Seismic Data

作　　者：刘志伟[1] 赵文津[1] 吴珍汉[1] 史大年[2] 

机构地区：[1]中国地质科学院,北京100037 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质学报》2016年第8期1692-1702,共11页Acta Geologica Sinica

基　　金：中央级公益性科研院所基本科研业务费项目"深反射地震数据处理技术研究"(编号:YYWF201506);中国地质调查局项目"青藏高原深部过程与资源环境效应研究"(编号:1212011220903);美国自然科学基金委员会(NSF);德国GFZ地学研究中心联合资助项目资助

摘　　要：INDEPTH Ⅳ深反射地震测线横跨可可西里-巴颜喀拉地块和东昆仑-柴达木地块,为揭示青藏高原东昆仑造山带深部构造提供了直接地球物理证据。针对地表和地下"双复杂"地质构造条件,地震数据处理中通过剩余折射波静校正技术、异常振幅噪声衰减技术和CRS优化叠加技术,获得了较高信噪比的地震反射叠加剖面。INDEPTH Ⅳ深反射地震剖面揭示,在东昆仑造山带岩石圈上、下地壳之间存在不连续的古洋壳反射同相轴,该反射界面应属古特提斯域松潘-甘孜洋壳向北俯冲遗迹,不连续特征反映中生代东昆仑-柴达木地块南缘属于被动大陆边缘碰撞带。利用INDEPTH Ⅳ深反射地震单炮、速度和叠加剖面等成果,综合解译数据,提出东昆仑造山带隆升过程的另一种模式,以助于深化东昆仑造山模式认识。The deep-reflection seismic survey in INDEPTH IV project was designed to stretch across the Kekexili-balyanlkalla block and East Kunlun-Qaidam block, and can directly obtain a geophysical evidence for discovery of East Kunlun Orogeny’s geologic structure. Considering on dual-complex geological conditions on surface and subsurface, a seismic profile with high signal-noise-ratios has been obtained by means of first-break refraction residual statics, abnormal amplitude noise suppression and CRS stacking. The new interpreted profile presents that an ancient oceanic crust’s reflection responses discontinuously exist between the upper and lower crusts of lithosphere. The response represents one northward subduction of Songpan-Ganzi Ocean during the Triassic period and the discontinuity reveals that East Kunlun-Qaidam block’s south borders belong to a passive continental margin. Based on INDEPTH IV’s shot gathers, velocity and stacking profiles presently interpreted, a new uplifting model of east Kunlun Orogenic belt come forward to enhance much knowledge to intracontinental orogenic belt.

关 键 词：深反射地震 东昆仑造山带 松潘-甘孜洋壳 INDEPTH IV 

分 类 号：P548[天文地球—构造地质学] P631.4[天文地球—地质学]