陕西秦岭泥盆系区域成矿大地构造演化

陕西秦岭泥盆系中有非常丰富的多金属矿产，其中以铅锌、金等最为著名。通过研发现，这些多金属矿产的成因与泥盆系经历的优越的大地构造演化历程密不可分。在早泥盆世，随着扬子板块北缘沿勉略一带裂谷化进一步发展形成初始洋盆而分裂出秦岭微板块（北秦岭），使秦岭造山带呈现出两洋（勉略洋和商丹洋）三块（华北板块、秦岭微板块和扬子板块）的大地构造格局。在这种格局下，秦岭微板块内发育了一系列伸展断裂，切割出一系列地堑和半地堑型盆地。沿这些盆地内部或边缘的深大断裂，深部岩浆和矿液得以上移，在海底形成了含铅、锌及金等多金属元素的喷流沉积，形成了多金属矿源层或矿床。在晚海西一印支期，华北、秦岭及扬子板块发生斜向穿时碰撞造山，完成了三板块“一体化”的过程，使华北板块北缘，扬子板块南缘及整个秦岭微板块发生了强烈的构造岩浆及变质作用，使早期泥盆系矿源层中的成矿元素重新活化迁移，在有利部位富集下来形成矿床。由于三板块的斜向穿时碰撞，导致秦岭造山带广泛发育了压性剪切带，形成了以八卦庙特大型金矿为代表的剪切型金矿。在燕山期，秦岭造山带进入了陆内造山阶段（地洼阶段），华北板块向秦岭微板块之下俯冲，导致秦岭造山带发生了广泛的构造、岩浆作用，使泥盆系矿?

ON THE EVOLUTION OF REGIONAL METALLOGENIC GEOTECTONICS OF THE DEVONIAN SYSTEM IN QINGLING, SHAANXI PROVINCE

There are considerably abundant multimetallic ore deposits in the Devonian system ofthe Qingling orogenic belt , Shaanxi, among which the most well-known deposits are Ph, Znand An deposits. Our studies indicate that the genesis of those multimetallic deposits is closeto the favourable processes of the tectonic evolution in the Qingling orogenic belt. Duringearly Devonian period, the Qingling micro-plate (North Qingling) was seperated from theYangtze plate with the formation of the initial ocean basin because of the development of therift along Mianlue in the northern edge of the Yangtze plate, which made the two oceans(Mianlue ocean and Shandan ocean) and three plates (North China plate, Yangtze plate andQingling micro-plate) appeared in the Qingling orogenic belt. As a result, a series ofstretching faults developed in the Qingling micro-plate and made a large number of grabenand semi-graben-basins formed. Along those faults within the basins and/or in the edges ofthe basins a great deal of magma and/or ore solution migrated upwards, thus producingspouting sediments bearing Ph, Zn and An elements in the sea bottom and forming multimetallic source bed and/or ore bed. During late Hercynian-Indosinian epoch, North China,Yangtze and Qingling micro-plates collided with each other by means of oblique diachronousconvergence and finished the uniting process of the three plates and made the southern edgeof the North China plate, the northern edge of the Yangtze plate and all the Qingling microplate undergo violent tectonic deformation, magmatism and metamorphism and consequentlymade ore-forming elements in the early Devonian source bed be activated, migrated and enriched in the favourable place to form ore deposit. Because of the oblique diachronous collision of the three plates, compression shear zones developed widely in the Qingling orogenicbelt to form a series of shear-type gold deposits, such as Baguamiao superlarge gold deposit.During Yanshanian period, the Qingling orogenic belt reached intracontinental orogenic stage(Diwa stage) and the North China plate underthrust towards the Qingling micro-plate, thusmaking those ore-forming elements activated, moved and gathered to form mineral deposits.Through the above three tecto-processes, magmatisms and mineralization, abundant polygenetic compound multimetallic deposits had been formed in the Qingling orogenic belt ofshaanxi province.