中国东南部中生代陆内岩浆作用的动力学背景

GEOODYNAMIC BACKGROUND OF THE MESOZOIC INTRACONTINENTAL MAGMATISM IN SOUTHEAST CHINA

根据叠置在华夏和扬子陆块的中生代岩浆岩的时代、岩石系列和岩石组合以及Sr、Nd同位素特征，分析中生代岩浆作用特提斯陆内俯冲和碰撞—古太平洋俯冲走滑的动力学背景。在230－150Ma间，特提斯构造域的影响是华北与扬子陆块的水平碰撞缩短，华夏西南部是离散陆块的陆内俯冲，其结果在华夏陆块形成大规模高Isr低εNd（t）的S型花岗岩。145－90Ma间，在特提斯构造域深部构造效应的基础上叠加了古太平洋的俯冲走滑，结果在中下扬子区形成高钾富碱钙碱性系列和橄榄安粗岩系列火山一侵入杂岩，在华夏陆块形成高钾钙碱性系列和双峰式火山—侵入杂岩。两陆块内A型花岗岩类的形成（＜92Ma），标志中生代陆内造山岩浆作用的结束。

Authors propose a dynamic model in this paper based on the ages, rock series and associa-tions and Sr-Nd isotopic characteristics of the Mesozoie intracontinental magmatic rocks over-laid Cathaysian and Yangtze Blocks. Main points of the model are the combination of intracon-tinental collision and subduction in Tethys tectonic regime with Paleo-Pacific ocean plate sub-duction-strike slip-extension in Pacific tectoniC regime- During 220- 150Ma, the horizontdlcollision of North China Block and Yangtze Block, as well as the intracontinental subduction ofsome divergent microcontinental terranes in the southwestern part of Cathaysian Block wereresulted from the influence of Tethys tectonic regime, which caused to form a volume of high-Isr and low-εND(t), S-type granites in Cathaysian Block. During 145- 9OMa, under the geody-namic background of subduction-strike slip-extension of Paleo-Pacific ocean plate overlapped onthe basis of deep tectonic process for Tethys tectonic regime, high-K alkaIine-rich calc-alkalineand shoshonitic volcano-plutonic complexes wete generated in Yangtze Block, and high-K calc-alkthee and bimodel volcano-plutonic coinplexes were generated in Cathaysian Block. The oc-currence of A-type peralkaline granits in Southeast China Coast indicates the end of the Meso-zoiC intracontinental magmatism-