南秦岭古生代热水沉积盆地与热水沉积成矿  

Paleozoic hydrothermal sedimentary basin and hydrothermal sedimentary mineralization in the Southern Qinling

作　　者：唐永忠 齐文[1] 刘淑文[2] 侯满堂 

机构地区：[1]陕西省地质调查院,陕西西安710054 [2]长安大学资源学院,陕西西安7100541

出　　处：《中国地质》2007年第6期1091-1100,共10页Geology in China

基　　金：中国地质调查局地质大调查项目(200110200029;[2005]13-8)资助。

摘　　要：扬子地块北部被动边缘的南秦岭古生代沉积盆地中,发育一套自早古生代—中生代以来的碳酸盐岩夹细碎屑岩沉积建造,形成规模巨大独具特色的以铅锌金为主的多金属成矿带。伸展构造体制下形成的裂陷或断陷型盆地中,正常水成沉积与热水沉积同盆共存。正常水成沉积中叠加的热水沉积是一个"突发事件或灾变事件",具有特殊的物质组成和产态。通过对区内沉积成矿盆地的识别、分级,二级沉积盆地中边缘部位常发育多个三级构造热水沉积成矿盆地,它受控于沉积盆地中的同生断裂,具有沉积岩相、热水沉积岩组合、显著成矿作用及物化探异常广布的特点。三级构造热水沉积成矿盆地是矿床定位的构造空间,四级热水沉积洼地为矿体(矿层)的容纳空间。区内热水沉积岩主要为重晶石(毒重石)岩、硅质岩、钠长石岩和铁碳酸盐岩类,铅锌重晶石等矿产多产于热水沉积岩中或上盘。热水沉积形成一般由早期的热水喷发交代→主期热水喷流→晚期热水喷气演变。早期的热水喷发交代往往沿矿液喷发通道,形成网脉状、角砾状矿化;主期热水喷流主要形成多金属及热水喷流相,形成块状、条带状、层纹状矿石或热水沉积岩;晚期热水喷气主要形成浸染状矿石和热水喷气岩石。An Early Paleozoic to Middle Mesozoic sequence of carbonate rocks with finely clastic rocks occurs in the Paleozoic South Qinling sedimentary basins at the passive continental margin of the northern part of the Yangtze plate. A huge and unique lead-zinc-gold polymetaUic metallogenic belt formed there. Normal sediments and hydrothermal sediments coexist in the same rift or downfaulted basins formed in an extensional regime. The hydrothermal sediments superimposed upon the normal sediments, which was a ＂sudden or catastrophic event＂, have the special material composition and mode of occurrence. Recognition and hierarchical division of the sedimentary ore-forming basins in this area Show that several third-order tectono-hydrothermal sedimentary subbasins usually occur at margins of second-order sedimentary subbasins. They are controlled by contemporaneous faults and characterized by particular sedimentary facies, hydrothermal sedimentary rock associations, significant ore-forming processes and wide distribution of geophysical and geochemical anomalies. The third-order tectono-hydrothermal sedimentary subbasins are tectonic spaces for localization of ore deposits, and the fourth- order hydrothermal sedimentary subbasins are spaces accommodating orebodies （ore beds）. The hydrothermal sedimentary rocks in the region are mainly barite （witherite） rock, siliceous rock, albite rock and ferro-carbonate rock. Mineral resources such as lead, zinc and barite mostly occur in the hydrothermal sedimentary rocks or in their hanging wails. The hydrothermal sedimentation generally evolved from early-stage hydrothermal eruption and replacement through main-stage hydrothermal effusion to late-stage hydrothermal exhalation. The early- stage hydrothermal eruption and replacement usually result in stockwork and brecciform mineralization along the conduits of ore fluid eruption. The main-stage hydrothermal effusion mainly gives rise to hydrothermal effusion facies and polymetaUic mineralization, characterized by massive, band

关 键 词：南秦岭 热水沉积盆地:热水沉积成矿 

分 类 号：P611.22[天文地球—矿床学]