论中国东北大陆裂谷系的形成与演化

ON THE ORIGIN AND EVOLUTION OF CONTINENTAL RIFT SYSTEM IN NORTHEAST CHINA

自中生代末期以来,东北地区形成了以松辽地堑为主体,联合下辽河裂谷、伊通-依兰裂谷、抚顺-密山裂谷以及邻近断陷盆地的大陆裂谷系,并向南北两端延伸,在亚洲东部构成一条大的裂谷带。这个大陆裂谷系的形成和发展是由中央向两侧展开的,与板块俯冲、弧后扩张密切相关。

Geological, volcanic and geophysical evindences reveal that the Northeast China has been essentially changed its geotectonic nature, and has been a continental rift system since the Late Mesozoic. This rift system consists of Songliao Graben (SLG), Xialiaohe Rift (XLR), Yi-tong-Yilan Rift (YYR), Fushun-Mishan Rift (FMR) and other adjacent block basins, which is much similar to the Basin and Range Province in west America. It links with Tancheng-Lujiang Rift through Bohai Sea to the South, and stretchs into the Soviet Union in the north.The Northeast Continental Rift System has been developing from the center to flank, especially to the east, the graben and rift successively formed from Songliao Graben to the continental margin, their contraction and closing was earlier in time one than another, corresponding volcanism reveals same regular. The pattern and evolution of the Northeast Continental Rift System is bound up with special epsiric surroundings of continental margin, back-arc basin and island arc. The Pacific Plate subduction intensified tectonic movement and impelled the upheaval of the mantle and the disruption of the continent, then formed island arc system. Accompanying occurrence of island arc system the subduction zone was far away from continental margin and intensified back-arc spreading, which further impelled occurrence of continental rift system. In a sense, plate subduction caused continental rift and back-arc basin, and the latter in turn buffered subduction, rifting is counteraction of subduction.