阿尔金碰撞造山带西段的构造特征

Tectonic evolution of the western segment of the Altyn Tagh collisional orogen, Northwest China.

根据阿尔金山西段前早古生代变质岩的岩石组成、沉积建造、变形变质作用改造历史、岩石地球化学特征等研究,将阿尔金碰撞造山带西段划分为3个构造单元:北阿尔金地块、中阿尔金地块(包括英格里克构造-蛇绿混杂岩带、肖鲁克·布拉克高压变质岩带和塔什萨依玉石矿高绿片岩相—低角闪岩相变质岩带)和南阿尔金地块(包括南阿尔金中—新元古界隆起带和阿尔金南缘复合构造-蛇绿混杂岩带)。提出该碰撞造山带经历了前长城纪古陆核形成阶段、长城纪—青白口纪不同基底联合阶段和早古生代洋陆转换阶段3个阶段的构造演化。

According to the composition, sedimentary formations, history of deformation and metamorphism and petrochemistry and geochemistry of pre-Paleozoic metamorphic rocks in the western segment of the Altyn Tagh Mountains, the western segment of the Altyn Tagh collisional orogen may be divided into three tectonic units：from north to south they are the northern Altyn Tagh block, the central Altyn Tagh block （including the Yinggelike tectonic-ophiolitic mélange belt, Xiaoluke Bulak high-pressure metamorphic belt and high greenschist-low amphibolite facies metamorphic belt of the Taxsay jade mine） and the southern Altyn Tagh block （including the Meso- and Neoproterozoic southern Altyn Tagh uplift and southern Altyn Tagh marginal tectonic-ophiolitic mélange belt）. Three stages are proposed for the tectonic evolution of the pre-Early Paleozoic Altyn Tagh coUisional orogen：the stage of pre-Changchengian paleocondnental nucleus formation, stage of combination of Changchengian-Qinghaikouan different basement units and stage of Early Paleozoic ocean-land transition.