中国东部中亚构造带及向环太平洋构造带的转化

A Discussion on the Tectonic Zone of Middle Asia and its Transformation to Tectonic Zone of Circum Pacific Ocean in Eastern China

中亚古亚洲洋的消失可由该地区大量晚元古后期－泥盆纪残余洋壳和高压变质带的存在来说明，其中大量８００～５５０Ｍａ蛇绿岩和高压变质带说明兴凯运动是主要造山期。加里东和华力西造山运动是其后续运动，早石炭世是一个转折期，早石炭世地层基本缺失，洋壳残片不再出现，变质作用突然减弱，表明中亚地区构造机制已逐渐转入大陆内部。石炭二叠纪地壳开始拉伸，形成了晚古生代裂谷并产生强烈岩浆作用。二叠纪末。早中生代全区隆起，残余海盆地消失，西伯利亚地台以其盾形前缘向南推移，形成推土机机制改变了加里东－华力西期的东西向构造格局，形成折接的类弧形构造，其东部为北东向构造，前缘为东西向，西部为北西向，总体形成宏伟的推覆断层及走滑断层系，早中生代中国东部环太平洋构造带以南北向为特征，由东而西的侧压力转换成剪切分量，加强了北东向的走滑和拖曳。在这一过程中，环太平洋构造以最接近的应力场和最低的地动能消耗、制动，继承和改造了晚末期中亚构造系，达到两个大地构造区系的交替和过渡。

The disappear of Paleoasian ocean may be proved by numerous remainders of ophiolitesand metamorphosed belts of high pressure from Late Precambrian to devonian in MiddleAsian,and a lot of 800～550 Ma ophiolites and high pressure metamorphosed belts indicatethat the main orogenic movement occurred during the Xingkai period and the successive oro-genic movement only did during the Caledonian-Variscan time. The early Carboniferous e-poch was the turning age,and was marked by the absence of strata, the disappear of ophio-lites and the suddenly weakened metamorphism,which indicate that the tectonic mechanismhad entered into the inner continent in Middle Asian area. During Permian-Carboniferous,thecrust began to pull apart,and resulted in the formation of late palaezoic rift and the intensivemagn1atism, During late Permian-early Mesozoic,the upwarping in all area occurred and theremained basins disappeared, when the shield front of Siberian platform migrated toward thesouth and formed the mechanism of bulldozer which changed the structure orientation of E-w of Caledonian-Variscan period,and resulted in the formation of arc-like structure with itsstructural lines of NE in the eastern part;SW in the western part;and E-W in the front mar-gin,and overall,the structure shows up by the magnificent thrust and shove fault system.The NE structure zones with shoving and dragging in the Middle Asian area were strength-ened by the shear subsidiary force from lateral compression of circum Pacific field.In thecourse the Middle Asian tectonic system was inherited,transformed and reformed at its latesttime by the circum Pacific tectonics with along approaching force field and the minimal con-sumption of geodynamic energy.