摘要
东天山土屋—延东斑岩铜矿的形成时代迄今尚存在争议。前人以矿区南侧凝灰质粉砂岩夹层中所含古生物化石及区域地层对比为依据,将含矿地层时代划归为石炭纪,并推测其成矿的构造环境属于哈萨克斯坦—准噶尔板块的活动陆缘——觉罗塔格石炭纪火山岛弧。近期一些研究者通过对区内各类地质体的同位素地质年代学研究,获得了中—晚泥盆世和早石炭世的年龄信息(390～36 0 Ma) ,认为含矿火山岩和矿化斜长花岗斑岩形成于中—晚泥盆世—早石炭世。据此提出土屋和延东斑岩铜矿形成构造环境应属于塔里木板块的活动陆缘,是泥盆纪岛弧火山-深成作用的产物。在前人研究基础上,笔者对土屋和延东斑岩铜矿区的矿化斜长花岗斑岩开展了锆石SHRIMP微区原位U - Pb定年研究,获得土屋和延东矿区矿化斜长花岗斑岩体的年龄分别为334±3Ma(95 %置信度)和333±4 Ma(95 %置信度)。测定结果表明,土屋和延东斑岩型铜矿床的形成时代应归属为晚石炭世早期或早石炭世晚期,成矿作用与石炭纪钙碱性岩浆浅成侵位有关。
The metallogenetic age of Tuwu—Yandong porphyry copper deposit in eastern Tianshan Mountain is in dispute. According to fossils found in the interlayer of tuffaceous siltstone and regional analogy of strata,some predecessors believed that the host volcanic rocks were formed in the active continent margin of the Kazakstan—Junggar paleo-plate during Carboniferous. Based on Middle Devonian—Early Carboniferous isotopic ages(390～360Ma)obtained in recent years,some others considered that the host volcanic rocks and mineralized plagiogranite porphyry were formed in the active margin of the Tarim Paleo-plate during Middle Devonian and mineralization should be resulted from Devonian island-arc volcanism and magmatic intrusion. However,zircon SHRIMP U-Pb dating shows that the mineralized plagiogranite porphyry was emplaced around 330Ma,indicating that the Tuwu—Yandong porphyry copper deposit was formed during Carboniferous related to high-level emplacement of calc-alkaline magma.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2005年第2期256-261,共6页
Acta Geologica Sinica
基金
国家重点基础研究发展规划项目(编号G199904201
2001CB409810)
国家科技攻关项目(编号2001BA609A-07-18A)资助的成果。
