用综合方法研究中国东部深部构造

<正> 近年来在我国获得大量的地质、地球物理和地球化学等资料的基础上,特别是将地表地质构造的研究与深部地质构造和新构造运动的研究结合起来,更加深和丰富了对大地构造的认识。 1957年,地质部航测大队首次在我国东部发现了郯城—庐江深大断裂带。同时,大量的地球物理工作,为我国早期油田的勘探与开发提供了地质构造的依据。六十至七十年代,利用人工地震研究地壳和上地幔的结构,提出了部分地区的详细地壳模型和地壳厚度。在我国某些地区开始了古地磁学的研究。

A STUDY OF DEEP CRUSTAL STRUCTURE IN EASTERN CHINA USING INTEGRATED GEOPHYSICAL DATA

This paper dwells on the results of the interpretation of integrated geophysical data (including: seismic wave velocity, gravity and magnetic field, heat flow, electroconductivity, etc. ) in Eastern China in order to determine the regional geophysical nature of the structures. It is discussed on the part of paraplatform, fold system, uplift and depression, continental rift, deep fracture etc.. The regional geophysical field data from Eastern China are compared with those from the other places of the world, showing the similarities and differences between them which are listed in Table 1.Crustal types may be divided mainly as the following. 1) platform. Songliao Basin, North China Plain and Yangtze region; 2) Paleozoic orogenic belt: South China; 3)Mesozoic-Cenozoic orogenic belt. Shanxi uplift; 4) continental rift systems Xia Liaohe River rift; and 5) marginal sea basin: South China Sea Basin. Contrast is also made beween their various characteristics of the regional geophysical fields, such as tectonic stability, total thickness, Bouguer anomaly, magnetic anomaly, heat flow, VPn, Vp upper layer, thickness of upper layer, Vp lower, thickness of lower layer, average crustal Vp, low velocity belt and high conduction layer.As a result of comparison of these data several problems concerning deep-seated structures of Eastern China are discussed: 1) the evolution of the deep-seatep crustal structures in platforms, 2) the possibility of older rock formations that are developed in the basement of Songliao Plain, 3) the features of deepseated geotectonic movements of the Mesozoic-Cenozoic and 4) the South China Sea Basin as a typical marginal sea basin.