扬子陆块西缘石棉大水沟岩片变形变质特征

DEFORMED AND METAMORPHIC FEATURES OF DASHUIGOU MICROLITHON,SHIMIAN IN THE WESTERN MARGIN OF YANGTZE LANDMASS

经近年研究，石棉大水沟岩片边界断裂为韧性剪切带，具逆冲-推覆性质，在中生代碰撞造山过程中逆冲叠置在扬子陆块之上。该岩片经历了晚二叠世裂谷变质、晚三叠世末至早中侏罗世滑脱-收缩动热变质和晚侏罗世热隆接触变质等三期主要变形、变质作用，尤其是后两期影响最深刻，奠定了现今热隆构造，并伴有赚矿床的形成。大水沟热隆，具陆陆碰撞地壳加厚，剪切增热，熔融岩浆底辟上隆的演化特点，属岩浆热隆。

Bourdary faults of Dashuigou microlithon are ductile shear zones being of thrusting and nap ping in character. The microlithon thrust upon Yangtze landmass during the Mesozoic collisional orogeny. It underwent the Late Permian rifting metamorphism, especially, late Late Triassic Middle Jurassic detachment-compressive dynamothermal metamorphism and Late Jurassic thermal dome contact metamorphism. They laid a foundation of Dashuigou thermal dome associated with tellurium ore deposit- Dashuigou thermal dome is a magmatic one which underwent collision thickening of crust, shear heating and magmatic diapir.