东北地区晚古生代构造演化及其石油地质意义

中国东北地区在古生代期间有3次重要的构造-岩浆事件，峰期年龄分别约为500Ma、320Ma和250Ma。500Ma的花岗质岩石与同期形成的高级区域变质岩伴生，东北各构造单元内均有记录，反映该区在加里东期经历了一次重要的造山事件；320Ma的花岗岩主要发育在大兴安岭地区，呈北东向展布，具有由俯冲到碰撞后成因的地球化学特点，是松嫩地块和额尔古纳-兴安地块碰撞拼合，形成统一佳蒙地块的重要事件；250Ma的花岗岩主要发育在东北南部和吉黑东部地区，是华北板块与佳蒙地块碰撞后伸展作用的产物。佳蒙地块形成后，主体隆升为陆，南部处于与古亚洲洋相连的大陆边缘。晚石炭世晚期—早二叠世，佳蒙地块处于伸展构造背景，发育了一系列北东向展布，被火山岩和正常沉积岩充填的断陷盆地，沉积环境具有北陆南海的格局。中二叠世，断陷盆地演化为巨大的海相沉积盆地。晚二叠世—早三叠世，华北板块与佳蒙地块发生陆-陆碰撞，残余洋盆消失，形成陆相沉积盆地。中二叠世海相盆地和晚二叠世陆相盆地内碳酸盐岩和暗色泥岩发育，具有良好的油气资源勘探前景。

Late-Paleozoic tectonic evolution and oil-gas potentiality in northeastern China

The three important events of tectonic-magmatism developed during Paleozoic in northeastern China, with the peak ages of 500Ma、320Ma and 250Ma, respectively. The granites with age of 500Ma are distributed in all tectonic units in the area and associated with the simultaneous high grade metamorphic rocks, representing Caledonian orogeny in northeastern China. The granites with age of 320Ma are mainly distributed in the Da-Xinganling Mountains, in NE trending, with a continuous geochemical evolution from subduction to post collision. It was an important event that an united continent(Jiameng continent) formed in northeastern China and neighbors. The granites with age of 250Ma are for the most part distributed in south and east parts of northeastern China. They are originated by extension after collision of North China continent and Jiameng continent. During Late-Carboniferous to Early-Permian, the south part of the united Jiameng continent was a passive continent margin connecting southwards with Paleo-Asia Ocean,where developed a series of faulted basins filled by terrestrial volcanics and sediments in north part and marine volcanics and sediments in south part. In Middle Permian, the faulted basins subsided continuously, a large marrine basin formed in the centre-south part of the Jiameng continent, where large thick sediments of marine carbonate and mudstone formed. In Late Permian-Early Triassic, as collision of North China and Jiameng continents along E-W trending Xilamulunhe fault and paleo sea basin extincted, a terrestrial sediment basin was formed in south part of the Jiameng continent. These Late Paleozoic basins are filled with thick sediments of mudstones and for the most part covered by Mesozoic-Cenozoic basins, it is worthy to be considered as a new field for oil-gas exploration.