摘要
钦杭成矿带位于华南板内,尽管是扬子与华夏古陆在新元古代拼接部位,但绝大多数矿床形成于中晚侏罗世至白垩纪。本文在梳理前人工作成果的基础上,将钦杭带及旁侧矿床归纳为两个成矿系列和三个成矿亚系列,即:新元古代海底喷流沉积型铜锌矿床成矿系列和燕山期与花岗岩有关的钨锡铜铅锌多金属矿床成矿系列,后者可以进一步分为中晚侏罗世斑岩-矽卡岩-热液脉状铜多金属矿床成矿亚系列,晚侏罗世与花岗岩有关的钨锡多金属矿床成矿亚系列和白垩纪与次火山活动有关的浅成低温热液型金银铅锌钨锡矿床成矿亚系列。进而讨论了各成矿系列和亚系列的主要矿产类型、基本特点、形成过程、时空分布关系和成矿规律。初步认为其成矿背景为:新元古代的块状硫化物铜锌矿形成于弧后或弧前盆地,由于成矿物质主要来源于地幔,因而更可能为弧前盆地;中晚侏罗世斑岩-矽卡岩-热液脉状铜多金属矿床可能是俯冲板片沿古钦杭结合部位发生局部重熔,形成高钾钙碱性花岗岩,然后上侵定位与成矿;而160～150Ma的大规模钨锡多金属成矿作用及大花岗岩事件可能与板片窗有关,钦杭带中段是板片窗的西部边界,也是壳幔相互作用的中心,因而有大量地幔物质参与成矿;135Ma之后,由于俯冲板片运动方向发生调整,从斜俯冲变成几乎平行大陆边缘运动,导致大陆大规模岩石圈伸展,相应绝大多数不同来源的矿产资源聚集在火山盆地和断陷盆地。此外,结合前人工作和以往工作的基础,提出了在钦杭成矿带进一步找矿勘查的一些思考。
The Qinhang belt is located along the Qinhang （Qinzhou Bay to Hangzhou Bay） or Shihang Shiwandashan Mt.to Hangzhou Bay） Neoproterozoic suture in South China,which separates the Yangtze craton and Cathaysian Blocks.The most ore deposits in the belt are Mesozoic age although they occurred along the Precambrian suture.Based on the previous researches we recognize these deposits in two episodes,i.e.Neoproterozoic marine exhalative Cu-Zn deposits,and Yanshanian granitoids related W-Sn-Cu-Pb-Zn deposits.The latter can be subdivided in Mid-Late Juarassic porphyry-skarn-vein polymetallic copper deposits,Late Jurassic granite related W-Sn deposits,and Cretaceous epithermal Au-Ag-Pb-Zn-Sn deposits.After descriptions of the basic characteristics,ore-forming mechanics,spatial-temporal distribution of these deposits it is proposed that the Neoproterozoic marine exhalative Cu-Zn deposits occurred in the foreland basins of the oceanic islands whereas the Mid-Late Juarassic porphyry-skarn-vein polymetallic copper deposits are related the high-K calc-alkaline granites derived locally from the remelt of the subducted Izanagi plate at 180~155 Ma along the ancient Precambrian suture.The large-scale Late Jurassic granite related W-Sn deposits associated with the crust-source granites with input of the mantle substances at 160～150 Ma,which are inferred to be the result from subducted plate window in the central part in South China and bounded in west by the Qinhang suture,where a lot of large and supper large tin and tungsten deposits developed.After 135Ma the subducted oceanic plate changed its motion direction to be along northeast,paralleling the Eurasian continental margin,which induced the large-scale lithospheric extension.Therefore,the all Cretaceous epithermal Au-Ag-Pb-Zn-Sn deposits developed within the volcanic basins and faulting basins at 120～90 Ma along the Eurasian continental margin.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2011年第5期636-658,共23页
Acta Geologica Sinica
基金
国家重点基础研究发展规划项目(编号2007CB411405)
国家自然科学重点基金项目(编号40930419)
中国地质调查项目(编号1212011120831)资助的成果
