CAJ | 학술논문

喀腊大湾位于北阿尔金中东段，为北东向阿尔金断裂与东西向阿尔金北缘断裂所夹持，区内遍布中酸性侵入岩。笔者选取喀腊大湾地区4337高地北花岗闪长岩岩体为研究对象来反演喀腊大湾地区构造演化。岩石地球化学数据表明，岩体为高钾钙碱性 I 型花岗岩，可能是下地壳中钾和高钾变质玄武岩在高压条件下部分熔融形成的。4337高地北花岗闪长岩岩体锆石 SHRIM PUPb年龄为（494．4±5．5） Ma ，表明其为晚寒武世岩浆活动的产物。结合岩体的地球化学、微量元素构造环境判别图解、年代学和区域地质背景的特征，判定其形成于与俯冲有关的活动陆缘（大陆弧）构造环境。同时，结合前人对喀腊大湾地区岩浆岩的研究，认为该区在早古生代发育一条活动陆缘（大陆弧）岩浆岩带，指示北阿尔金局限洋盆在晚寒武世早中奥陶世向南俯冲在中阿尔金地块之下。通过对比北阿尔金东西段报道的中酸性侵入岩年龄数据，认为北阿尔金局限洋盆西段经历了更长时间的俯冲，整体呈东早西晚的剪刀状闭合。
객석대만위우북아이금중동단，위북동향아이금단렬여동서향아이금북연단렬소협지，구내편포중산성침입암。필자선취객석대만지구4337고지북화강섬장암암체위연구대상래반연객석대만지구구조연화。암석지구화학수거표명，암체위고갑개감성 I 형화강암，가능시하지각중갑화고갑변질현무암재고압조건하부분용융형성적。4337고지북화강섬장암암체고석 SHRIM PUPb년령위（494．4±5．5） Ma ，표명기위만한무세암장활동적산물。결합암체적지구화학、미량원소구조배경판별도해、년대학화구역지질배경적특정，판정기형성우여부충유관적활동륙연（대륙호）구조배경。동시，결합전인대객석대만지구암장암적연구，인위해구재조고생대발육일조활동륙연（대륙호）암장암대，지시북아이금국한양분재만한무세조중오도세향남부충재중아이금지괴지하。통과대비북아이금동서단보도적중산성침입암년령수거，인위북아이금국한양분서단경력료경장시간적부충，정체정동조서만적전도상폐합。
Kaladawan area of the eastern Altun Mountains of Xinjiang is tectonically located between the NE‐trending Altyn Tagh strike‐slip fault and the EW‐trending northern Altyn Tagh fault ,where the intermediate‐acid intrusive rocks are wildly distributed .The granodiorite in the north of Highland 4337 is selected to study the tectonic evolution of the Kaladawan area .The geochemical data of the intrusion suggests that it is high‐K calc‐alkaline I‐type granitic rock which was likely derived from a partial melting of the intermediate‐ to high‐K meta‐andesitic‐basaltic rocks under high pressure .Zircon U Pb age obtained by SHRIM P from the granodiorite is (494 .4 ± 5 .5) Ma ,implying that it was emplaced in the Late Cambrian period .Integrated with geochemistry ,trace element discrimination ,geochronology , and regional background ,it is inferred that the granodiorite was formed in a subduction‐related active continental margin (continental arc) .In combination with the previous studies of magmatic activity in Kaladawan area ,we suggest that the central Altun block were developed in Early Paleozoic into an active continental margin (continental arc) ,and a magmatic belt were caused by the southward subduction of an oceanic crust to central Altun block during Late Cambrian to Early‐Middle Ordovician .Compared to the ages of the intermediate‐acid intrusive rocks of north Altyn Tagh area ,the evolution of western and eastern parts is different .The west of north Altyn Ocean subduction lasted relatively longer than the east ,and the syn‐collision stage in the east was earlier than in the west .