试论华北地台西北缘多金属硫铁矿控矿因素

CONTROLLING FACTORS OF THE MINERALIZATION OF POLYMETALLIC PYRITE ALONG THE NORTHWESTERN MARGIN OF NORTH CHINA PLATFORM

裂谷系-克拉通边缘断陷带-同生断裂-断陷盆地是华北地台西北缘元古宙层控型多金属硫铁矿最重要的控矿格局。矿床具有明显的层控、时控和岩控特征。枢扭带线型构造控制一、二级盆地及矿带、矿田的空间展布;同生断裂控制有硫化物堆积的三级盆地;伸展构造在横向上的互补作用导致岩(矿)层走向上的伸、缩变化;低补偿与超补偿沉积界面为硫化物沉淀提供了有利的物理、化学场;同沉积火成活动为含矿热液的对流循环提供了足够的能量。深入研究并正确认识上述控矿因素的控矿作用对于指导该区乃至同类矿床的普查找矿和成矿预测具有重要意义。

Across the northwestern margin of North China platform,a serise of rift systems,rifting zones around cratons,contemporaneous faults and fault basins make up a tectonic framework which is extremely critical to controlling the mineralization of polymetallic pyrite deposits over the Proterozoic period.Particularly speaking,the linear hinge structures controlled the spatial distributions of the first-and second- order basins,ore belts and ore fields while the contemporaneous faults kept under their jurisdiction the third-order basins with vast accumulation of sulfide in them. The lateral mutual compensation between the extending structures caused the rock and ore bdes to lengthen or shorten along strike whereas the alternative shift between the short-and extra-supplements of sediments near the depositional interfaces created a physiochemical environment which was highly favourable for sulfide precipitation. A syndepositional volcanic activity,the final ore-controlling factor,provided energy enough for the circulation of the ore-bearing hydrothermal solutions.Apart from all the above mentioned factors,stratigrphy,chronology and lithology showed exclusivity to a certain extent in the sulfide mineralization.Deepening the researches on the roles of the different ore-controlling factors in regulating the mineraliztion will help not only exactly make metallogenic prognosis but direct the reconnoitring and prospecting for the study area's polymetallic pyrite deposits,even the mineral resources of their kinds where else.