东天山吐哈盆地南缘古生代活动陆缘残片:中亚地区古亚洲洋板块俯冲的地质记录  

Paleozoic active margin slices in the southern Turfan-Hami basin:geological records of subduction of the Paleo-Asian Ocean plate in central Asian regions

作　　者：李锦轶[1] 王克卓 孙桂华[1] 莫申国[1] 李文铅[2] 杨天南[1] 高立明[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]新疆地质调查院第一区域地质调查所,乌鲁木齐830011

出　　处：《岩石学报》2006年第5期1087-1102,共16页Acta Petrologica Sinica

基　　金：本项研究得到了国家科技部973项目(编号为2001CB409810);中国地质调查局国土资源调查项目(DKD9902002)的资助。

摘　　要：本文根据对已有地质资料的综合研究,系统论述了吐哈盆地南缘古生代活动陆缘残片的时空分布、岩石组合和岩石化学特征,在此基础上对古亚洲洋构造演化进行了简要的探讨。该区活动陆缘残片由奥陶纪-志留纪(?)、泥盆纪、石炭纪火山沉积岩系和泥盆纪、石炭纪深成岩组成。这些不同时代岩浆岩的时空分布揭示出该区弧岩浆前锋带的演化具有向南逐渐迁移的特点。这些不同时代的火山岩和深成岩在岩石组合和岩石化学方面都类似于钙碱系列弧岩浆岩。它们的这些特征,结合它们的区域地质背景,使我们得出如下初步结论:它们的形成演化与以南侧康古尔塔格碰撞带中的洋壳残片为代表的古洋岩石圈板块向西伯利亚古板块之下的俯冲有关;它们很可能与出露在阿尔泰山南侧、蒙古南部和大兴安岭中部等地的类似杂岩一起构成了古亚洲洋中西伯利亚古板块活动陆缘;该活动陆缘的发育,揭示出古亚洲洋板块向西伯利亚古板块之下的俯冲在奥陶纪至石炭纪期间一直在持续进行。Based on analysis of available geological and geochemical data, this paper states temporal and spatial distributions, rock assemblages and petrological features of slices of the Paleozoic active margins in the southern Turfan-Hami basin, and then briefly discusses tectonic evolution of the Paleo-Asian ocean. The slices consist mainly of Ordovician-Siliurian （？）, Devonian and Carboniferous volcano-sedimentary sequences, and Devonian and Carboniferous plutons. The temporal and spatial distribution of those magamtic rocks with various ages implies that the evolution of the magmatic front in the area is characteristic of southwards gradually migration. Those various magamtic rocks are similar both in rock assemblages and geochemistry to the calc-alkaline series ones of the island-arc type. Their above features, in combination with their regional geology, make us get primary conclusions that occurrence of the slices is related to subduction of the oceanic lithosphere plate, which is represented by oceanic remains within the Kangguertg Carboniferous collisional belt, northward under the Siberian paleoplate, and that these slices probably constituted the active continental margin of the Siberian paleoplate in the Paleo-Asian ocean with similar slices in the Altay mountains, southmost Mongolian and central Great Khing＇an ranges. The occurrence of the margin implies that subduction of the Paleo-Asian oceanic plate under the Siberian paleoplate continuously developed from the Ordovician through Carboniferous.

关 键 词：奥陶纪至石炭纪 活动陆缘残片 吐哈盆地南缘 古亚洲洋板块俯冲 中亚地区 

分 类 号：P542.4[天文地球—构造地质学] P534.2[天文地球—地质学]