东秦岭深源浅成型花岗岩的成矿作用及地质构造背景

Mineralization and Tectonic Setting of Deep-hypabyssal Granites in East Qinling Mountain

东秦岭位于华北板块与扬子板块之间的拼合带———秦岭造山带的东段。该区构造岩浆活动强烈 ,有色金属、贵金属的成矿作用发育 ,是中国著名的Mo ,W ,Au多金属成矿带 ,也是中国最大的Mo,Au ,W等矿产基地与重要的矿集区之一。通过深源浅成型花岗岩的特征、形成机制和成矿特点的研究 ,发现成矿多与中生代燕山期 (170～ 10 0Ma)的深源浅成型花岗岩类有关 ,并生成一系列斑岩_爆破角砾岩型矿床。矿床具有深源、与岩体同时、同空间以及岩体的成矿元素丰度高等特点。矿床类型与岩浆成分有关 ,表现出明显的成矿专属性。矿床的形成受区域构造演化作用的控制 ,成岩成矿作用是燕山期中国东部在陆内俯冲的背景下 ,岩石圈巨大减薄 ,引起软流圈抬升和地幔上涌造成的。

The East Qinling Mountain is located in the eastern part of Qinling orogen, the convergence zone of the North China plate and the Yangtze plate, where the crust movement is rather strong due to the relative motion, subduction and collision between the two plates. The tectonic_magmatism here is intensive, and the nonferrous metallic and noble metallic mineralizations are well developed. The East Qinling Mountain is a famous polymetallic belt of Mo, W and Au etc., and one of the largest Mo, W and Au concentrated area in China. The mineralizations here are mostly related to the Yanshanian deep_hypabyssal granitoids (170～100 Ma), forming a series of deposits of porphyry type and explosion_breccia type. The deposits are characterized by deep sources, synchronism, the same space and high content of ore_forming elements in rock bodies. The deposit types are related to the components of rock bodies, which obviously show the metallogenic specialization. The ore_forming process is controlled by the regional tectonic evolution, and the diagenesis and mineralization result from the uplifting of lithosphere and upwelling of mantle caused by the strong lithosphere thinning under the condition of intracontinental subduction in Yanshanian period in eastern China. The deposits are an important component part and representative evidence of 'the metallogenic explosion' in Mesozoic in eastern China, and seem to be the integrated results of regional tectonic evolution, magmatism and mineralization.