摘要
钦杭成矿带是扬子地块与华夏地块自新元古代以来的碰撞拼接带,后来在不同的地质历史时期形成了不同类型的矿床和相关的岩石。在侏罗纪形成两套成岩成矿系列,一套为中侏罗世(180～170Ma)与斑岩-矽卡岩-热液脉状铜金多金属矿床及其有关的钙碱性花岗闪长岩类;另一套为晚侏罗世(160～150Ma)与云英岩-石英脉-矽卡岩钨锡多金属矿床及其有关的钙碱性-碱性花岗岩类。本文对比了上述两个系列成矿花岗质母岩的空间分布、年代、岩石地球化学和Sr-Nd同位素特征,并探讨了二者形成的构造动力学背景差异:前者可能是由于古太平洋俯冲板片沿钦杭断裂带发生局部重熔形成的,后者形成于华南岩石圈大规模伸展减薄的环境下,两者的形成过程均有地幔物质参与,但是晚侏罗世与钨锡有关的花岗岩地幔贡献可能少一些。
Located in the interior of South China, the Qin-Hang （Qinzhou Bay to Hangzhou Bay） metallogenic belt was formed by the collision between the Yangtze craton and the Cathaysian block in late Neoproterozoic. Most ore deposits in the belt were formed in Mesozoic although different types of deposits occurred in different geological periods. Studies show that Mesozoic rock-forming and ore-forming processes could be subdivided two categories, i.e., Mid-Jurassic （180～170 Ma） porphyry-skarn-vein Cu polymetallic deposits and related granodiorites, and Late Jurassic （160～150 Ma） greisen-quartz vein-skarn W-Sn polymetallic deposits and related granites. In this paper, these two kinds of granitic source rocks were compared with each other in such aspects as spatial-temporal distribution, chronology, geochemical, Sr-Nd isotopic characteristics and tectonic settings. The former was derived locally from the remelting of subducted ancient Pacific plate along the Qin-Hang fault zone, whereas the latter was resulted from subducted plate windows in the central part of South China in a continental crustal extension and thinning setting. Abundant mantle materials were involved during the two types of rock-froming and ore-forming processes; nevertheless, less mantle materials were involved in the formation of Late Jurassic granitoids related to W-Sn deposits.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2013年第4期463-484,共22页
Acta Petrologica et Mineralogica
基金
国家自然科学面上基金(41273043)
国家重点基础研究发展规划"973项目"(2012CB416704)
地质调查工作项目(1212011220523)
国土资源部公益性行业科研专项经费项目(200911007-11)
