陕西柞-山-商晚古生代拉分断陷盆地动力学与成矿作用

采用构造-岩相学和构造-热水沉积岩相填图研究，认为陕西柞水-山阳-商县（柞-山-商）晚古生代拉分盆地，在早古生代扬子板块北被动陆缘残余洋盆基础上，经历了志留纪-早泥盆世北秦岭岛弧造山带-残余洋盆转换过程。在中泥盆世演化为秦岭微板块北缘拉分断陷盆地，晚泥盆世叠加了深源碱性热流体叠加作用明显，形成了铁白云石钠质角砾岩相带，并发生了构造反转。石炭纪陆缘拉分盆地进一步发展演化为残余海盆萎缩封闭。这种造山带-沉积盆地-岛屿构造耦合与转换过程记录了由洋盆-岛弧碰撞造山转换为陆-陆碰撞造山过程。该拉分盆地中具有明显的区域成矿分带，与多期成矿成岩地质作用有关，在造山带-沉积盆地-岛屿构造耦合与转换中，中泥盆世柞-山-商拉分断陷盆地的四周被古陆块和造山带分隔，陆-陆碰撞过程驱动了造山带流体发生大规模排泄到该盆地内，在该拉分断陷盆地内形成了大规模热水沉积成岩成矿，各类热水沉积岩相发育。在该拉分盆地中，近东西向和北东向同生断裂作用形成了次级断陷盆地，为热水沉积成岩成矿提供了沉积容纳空间。热水沉积成因的银多金属-重晶石-菱铁矿矿床定位于三级和四级热水洼地。晚泥盆世-石炭纪近南北向的岩石圈地幔收缩，陆-陆碰撞收缩成为垂向热传输主要驱动力源，导致了陆壳尺度上碱性热流体被挤压垂向排出到陆表残余海盆之中，本区脉状富金镍钴铜矿与晚泥盆世-石炭纪深源碱性热流体隐爆作用形成的碱性铁白云石钠质角砾岩带密切有关。类卡林型金矿定位于该盆地上部基底构造层和盆地热水浊流沉积相内，主要与后期脆韧性剪切带有密切关系。

Dynamics of the Late Paleozoic Apart pull Basin and Its Relationship with Mineralization of Gold silver polymetallic barite siderite Deposits in Zha Shan Shang,Shaanxi Province

 Based on re construction and restoration of geotectonic paleogeographic position and tectonic lithofacies, the Paleozoic sedimentary basin of Zhashui Shanyang Shangxian in Shaanxi Province could be the apart pull basin on the north passive margin of the Qinling sub plate block. This apart pull basin might have been developed on the residue oceanic basin on the north passive margin of the Yangtze plate, and undergone transformation of arc orogeny and residue oceanic basin during the Silurian Devonian age. Furthermore, this basin might be superimposed by deep sourced, alkaline hydrothermal fluid during the Late Devonian Period, resulted in lithofacies zones of ankerite albite breccia and inversion of the basin. Finally, it had been advanced into a remain sea basin to be shrinking and closed during the Carboniferous Period. Transformation and coupling process of orogeny sedimentary basin island structure may be records form the arc land type orogeny to land land type orogeny. Obvious regional mineralization zonation in this basin may be possibly related to poly diagenesis mineralization. Firstly, a variety of hydrothermal sedimentary lithofacies are well established in the basin which disclosed that hydrothermal diagenesis mineralization at the large scale took place in the basin. On the one hand, this could be that hydrothermal fluids from the orogeny belt migrated at the large scale into the basin enclosed by paleo landblock and orogeny during the transformation and coupling process of orogeny sedimentary basin island structure. On the other hand, third and fourth order basins controlled by NE and EW trending synfaults offered sedimentary capacity for the hydrothermal mineralization. Mapping of sublithofacies and microlithofacies may help to delineate their distribution of topologic structure. Secondly, lithofacies zones of ankerite albite breccia in the remain sea basin closely related to vein type of Au Ni Co Cu deposits at the higher grades were formed by cryptoexplosion of deep sourced, alkaline hydrothermal fluids. The fluids might be driven by mainly vertical upping force during land land type collision at the south north direction shrinking of lithosphere. Finally, Carlin like gold deposits are hosted in the upper part of basin base structure layer and lithofacies of hydrothermal turbidity at the basin were controlled by the late brittle ductile shear zone in the area.