东北亚跃进山拼贴带及邻域岩石圈结构特征的地电学证据

为进一步查清东北亚完达山地体与两侧的佳木斯地块、兴凯地块间接触关系以及对跃进山拼贴带域沉积盆地油气条件的控制作用，布设5条MT剖面，计长1104 km.结果显示:(1)研究区地电学结构主要特征为佳木斯地块从中部向南北两方向，这一稳定地块的“高阻核”减薄，兴凯地块的高阻块体自东而西逐渐加深增厚，完达山地体在南部具有较多的高阻块体，向北渐少.(2)完达山地体西南端呈一“牛角”形状范围把佳木斯地块和兴凯地块分开；与原认识的完达山地体、佳木斯地块在同江-宝清-当壁一带贴合的位置相比，从宝清开始向南移至麻山-桦林一带.(3)完达山地体构造成因包括两部分，一是俯冲引起的拼贴，二是软流圈物质的热上涌；佳木斯地块内所存在的“高阻核”边界可能是该地块东界.(4)4个沉积盆地除勃利盆地外，另外3个盆地的基底间或存在规模不大的高阻块，大多范围分布着高导带，对盆地的成烃环境是有利的.

Geoelectrical evidence for characteristics of lithospheric structure beneath the Yuejinshan collage zone and its vicinity in Northeast Asia

To make a thorough investigation of the contact relationship between the Wandashan terrane and Jiamusi massif and Xingkai massif on its both sides in Northeast Asia, and its controlling effect on the oil-gas conditions of the sedimentary basin in the Yuejinshan collage zone, we have deployed 5 magnetotelluric (MT) sounding profiles with total length 1104 km. The survey results are as follows: (1) In the stable Jiamusi massif, the high-resistivity core becomes thinner along the middle toward north and south. In the Xingkai massif, the high-resistivity body tends to be deeper and thicker from east to west. And in the Wandashan terrane there are more high-resistivity bodies in south than in north. (2) The southwest part of Wandashan terrane which shows an “ox horn” shape separates the Jiamusi massif from Xingkai massif. Compared with the previously determined joint position of the Wandashan terrane and Jiamusi massif around Tongjiang-Baoqing-Dangbi, the new position moves to the south of Baoqing to Mashan-Hualin. (3) There are two possible causes for the formation of the Wandashan terrane: the collage caused by subduction and thermal upwelling of asthenospheric materials. Maybe the edge of the high-resistivity core in the Jiamusi massif is the eastern boundary of the massif. (4) Among the 4 basins, except for the Boli basin, high-conductivity zones or small high-resistivity bodies exist in most areas of the basements of the other basins which are favorable for the generation setting of hydrocarbon.