| Northeast China is located in the east part of the Central Asian orogenic belt between the Siberia Plate and north China Plate. Under the alternative tectonic effect of the Paleo-Asian Ocean and the Paleo-Pacific Ocean, the Northeast China has developed very complex tectonic patterns. Therefore, the study of deep crust tectonic structure of this region has a very vital scientific significance to reconstruct the tectonic evolution of Central Asian orogenic belt and to learn the deep crust geodynamic processes. Furthermore, the northeast region is an important energy base in China, thus, the study of deep crust tectonic structure of this region also has a very vital energy significance to learn the relationship between the deep crust matter-energy exchange and the surface energy resource zone development.With the support of project《Experimental Tectonic Research of Songliao Basin Crust Transect》, author managed to make geological explanation of“Deep Seismic Reflection Profile from Suihua to Hulin County in Northeast China”. The purpose of this paper is to realize and establish the deep crust structure of the area crossed by this seismic profile, and build up a bridge to connect deep processes and shallow tectonic deformation.Deep Seismic Reflection Profile from Suihua to Hulin County in Northeast China is the first deep seismic reflection profile, whose two-way note time reached 50 seconds. In this paper, author adopted seismic reflection fabric zone theory to realize the deep crust structure of the area crossed by this seismic profile, and collected more information from other geophysical methods to support establish the deep crust structure model of the area crossed by this seismic profile. Except these, author adopted the Terrane Tectonics theory to divide the terranes in the area crossed by this seismic profile.The Deep Seismic Reflection Profile is divided into 7 terranes: Songliao– Zhangguangcailing Terrane, Heilongjiang Terrane, Mashan Terrane, Baoqing– Mishan Terrane, Yuejinshan Terrane, Nadanhada Terrane and Matveyevskoye– Nakhimovsky Terrane.The reflection characteristics of the profile show that the continental crust in eastern part of Northeast China is not a whole block. The Moho surface reflection appears in the depth of about 29-42km, the diversity of Moho reflection characteristics prove that the crust in eastern part of Northeast China was not formed simultaneously. Moho reflection from Songliao Basin to Zhangguangcai Mountain represents a continuous clear reflection, which the relatively shows young age crust characteristics and absence of old (Precambrian) crystalline basement within the basin. Under the eastern edge of Songliao basin the seismic profile reveals a dipping reflection in the upper mantle, which is related to the existing of a low-angle westward sunk oceanic slab between the Zhangguangcai Mountain and Jiamusi region. Moho reflection of Jiamusi region appears to be discontinuous and fuzzy, which is the typical characteristic of older Moho reflection. Baoqing section once again shows clear and continuous young Moho reflection. Hulin Moho reflection displays a series of discontinuity, indicating an ancient crust that is likely to extend to Xingkai region, Russia. In addition, in the middle crust of Mashan region and Yuejinshan region exist two sub-horizontal reflections, which are related to the detachment structure, the depths of the reflections are 18-20km and 20-25km, the detachment structure indicate that Heilongjiang Group, Mashan Group, and Yuejinshan Group were deformed by the eastward thrust belt. |
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