MT成果数据管理系统在岩石圈电性结构研究中的应用——以东北地区为例

The application of the data management system of MT results to the study of electrical structure of the lighosphere: a case study in Northeast China

中国东北地区位于古亚洲洋构造域与滨太平洋构造域的叠置部位,受多期次的构造活动与岩浆作用的共同影响,其岩石圈结构复杂,为获得该区域的岩石圈的电性结构特征,以MT成果数据管理系统为技术手段,开展岩石圈尺度范围内的壳—幔电性结构的研究。笔者基于MT成果数据管理系统的查询、检索等功能,提取出研究区的壳—幔电性信息,对这些信息进行加工处理,得到了研究区的壳内低阻层分布特点与岩石圈厚度分布特征。研究表明,东北地区的岩石圈的电性结构特征为:1岩石圈的厚度呈现"西厚东薄"的变化特征;2不同盆、山结构表现出不同的岩石圈隆凹特征;3镜泊湖火山岩分布区对应软流圈的隆起区,其隆起可能与岩浆上涌有关。这些信息的获取为区域构造演化及动力学研究提供支撑。

Northeast China is located in the overlapping parts of Ancient Asia tectonic domain and Pacific tectonic domain,and the region has experienced multiperiodic tectonic activities and strong magmatism. Plate collage and orogenesis occurred in pre-Mesozoic,and interplate tectonic transformation took place in Mesozoic-Cenozoic; in addition,there are some complex geological structures. To detect the lithosphere electrical structure of the region,the authors conducted the crust-mantle electrical structure study by a data management system of MT results. The crust-mantle electrical information of Northeast China was extracted by use of the query function and the searching function of the management system. The crust low-resistivity layer distribution and the lithosphere＇s thickness distribution of the study area were obtained by processing the information obtained. Some conclusions have been reached： 1 The lithosphere thickness change is characterized by the relative thinness in the east and comparative thickness in the west. 2 Different basins and mountains show different uplift-depression lithosphere characteristics. 3 The asthenosphere uplift in Jingbo Lake volcanic area and the uplifting might have been related to magma upwelling. This information could provide support for the study of regional tectonic evolution and dynamics.