摘要
在美国高度发展的石油地震反射剖面测量方法技术已通过COCORP研究机构应用于研究大尺度的大陆地质和大地构造问题.COCORP是大陆反射剖面测量协会的缩写.该方法应用五个大型卡车震动器组合做震源,应用9.5公里长,2304个检波器、96道的排列接收.震源时间函数是由8—40Hz扫描.测量参数是标准的24次共深度点叠加.一般都能得到基岩内部反射界面的数据,其深度有时达到40～50公里.在美国已经在14个不同的地点做了2400公里以上的测量剖面.这些主要地质构造的三维的或者深度的观测,提供了新的重要地质特征的认识.诸如汇合板块边沿和大陆一大陆碰撞带:主要的断裂、主要的基底断块隆起和地震构造带等.有时地面观察和研究断层也能够确定地壳中的深部断裂.这些成果是对地面地质和其它地球物理方法的观测结果的补充和综合.这个方法当然完全可能有效地在中国应用来进行区域的研究诸如印度—欧、亚碰撞带,它包括有:印度一雅鲁藏布缝合线;西藏高原一唐古拉山带;南山和天山褶皱带;东中国中部深断裂和山西地堑等所举出的少许几个例于.中国的地质和大地构造的特殊性质,使上述重要的地壳特征的研究引起了特殊的科学兴趣.
Abstract
In the United States the highly developed seismic reflection profiling technique of the petroleum industry is applied to study of large-scale problems of continental geology and tectonics through the COCORP project. COCORP stands for Consortium for Continental Reflection Profiling. The VIBROSEIS* technique is used with five large truck-mounted vibrators as elements of the source array and a 91/2-km, 2304-element, 96-channel array as the receiver. The source time function is an 8-to 40-Hz upsweep,and survey parameters are normally arranged for 24-fold common depth point stacking. Data are commonly obtained from intrabasement reflectors, and depths as great as 40 to 50 km are sometimes sampled. Over 2400 km of profiling have been surveyed at 14 different sites in the United States.These observations of the third, or depth, dimension of major geological structures have provided important new understanding of features such as convergent plate margins and continent-continent collision zones, major rifts, major basement block uplifts, and seismotectonic zones. Fractures deep in the crust can sometimes be identified by tracing them to the surface where they aan be seen and studied. The results complement and integrate the observations of surface geology and of other types of geophysics.The method could almost certainly be applied advantageously in China to study areas such as the India-Eurasia collision zone, including features such as the Indus-Tsangpo suture; the Tibetan Plateau including the Tanglha zone; the Nan Shan and Tien Shien fold belts; the east-central China depth fractures and the Shanxi graben, to cite just a few examples. The unusual nature of the geology and tectonics of China causes special scientific interest in such major crustal features.
论文详情