摘要
火山成因块状硫化物矿床越来越受到重视,喀腊达坂铅锌矿位于北东向阿尔金走滑断裂与东西向阿尔金北缘断裂夹持的喀腊大湾地区,是阿尔金北缘红柳沟—拉配泉金、铜、铁及多金属成矿带中唯一大型铅锌矿床。矿区主要出露奥陶系下统卓阿布拉克组火山沉积岩系,呈近东西走向,以向北中等角度倾斜的单斜层为特点,倾角30°~58°;矿化严格受火山沉积岩特定层位和岩性控制,即矿体均产于卓阿布拉克组第四亚组的中酸性火山岩(流纹岩、英安熔岩、英安质晶屑凝灰岩)中,矿体具有层状、似层状特点,产状稳定延伸大;最大矿体走向延伸超过2400m,倾向延深大于900m。主要有用组分Pb、Zn,伴生有用组分Cu、Au、Ag、S等。主要蚀变类型有黄铁矿化、硅化、绢云母化,地表氧化带形成黄钾铁钒化和褐铁矿化。矿石平均铅同位素组成为^(208)Pb/^(204)Pb=38.1169、^(207)Pb/^(204)Pb=15.6278、^(206)Pb/^(204)Pb=18.4684,显示矿石的铅具有上地壳铅和造山带铅的混合来源;矿石硫同位素组成平均+8.28‰,代表了海相沉积岩来源的硫与岩浆岩来源硫的混合;矿石稀土元素配分曲线与矿区及喀腊大湾地区中酸性火山岩的稀土元素配分曲线具有一致性或者相似,说明矿石与含矿中酸性火山岩具有一致的成因与来源;矿石微量元素特征显示Nb、Ta负异常与Ba的正异常,反映出存在海相沉积岩物质的混入,并具有岛弧成矿构造环境。含矿火山岩锆石SHRIMP U-Pb年龄482~485Ma,代表了矿床的形成时代为早古生代早奥陶世。综合喀腊达坂铅锌矿地质地球化学特征的研究,确认其属于火山成因块状硫化物矿床(VMS型)。所以,喀腊达坂铅锌矿成矿过程可以概括为:在早古生代奥陶纪早期北阿尔金洋发生向南的板块俯冲,板块俯冲作用导致俯冲带下盘的洋壳及其上的海相沉积物和俯冲带上盘的陆壳发生部分熔融,形成了中酸性�
The volcanogenic massive sulfide （VMS） type deposit has received much attention in the past years. As the largest Pb Zn deposit in the Lapeiqun Hongliugou Au Cu Fe and polymetallic metallogenic belt of northern margin of Altun Mountains, the Kaladaban Pb Zn deposit is located within the area sandwiched between the NE striking Altun strike slip fault and EW striking northern Altun fault. Near EW trending volcanic sedimentary rocks of lower Zhuo’abulake Formation of Ordovician System crop out in the mining area, characterized by a monocline with medium angle northward dipping at 30～58. The Pb Zn metallization is controlled by a specific stratigraphic horizons of volcanic sedimentary rocks; in other words, all Pb Zn ore bodies occur in the intermediate felsic volcanic rocks of the 4th member of Zhuo’abulake Formation （i.e. rhyolite, dacitic lava and dacitic crystal tuff）. The ore bodies are of stratiform or stratiform like features with stable occurrence and large extension. The largest Pb Zn orebody extends more than 2400m along trending direction and more than 900m’s extension along dipping depth. The useful components of the ore are mainly Pb and Zn with associated elements of Cu, Au, Ag and S. The main alteration is pyritization, silicification and sericitization, with jarositization and limonitization occurring in the oxidized zone of the surface. The average Pb isotopic compositions of 12 samples from the deposit are 208Pb/204Pb=381169, 207Pb/204Pb=156278 and 206Pb/204Pb=184684, which indicates that the Pb of the ores came from the mixture of the upper crust and orogenic belt. The average 34S values of 15 samples （＋828‰） suggest a mixed marine sedimentary and magmatic sulfur source. The chondrite normalized REE distribution patterns of the Pb Zn ore are similar to that of the intermediate felsic volcanic rock in the ore district and in the Kaladawan area, showing that the ore and ore bearing intermediate felsic volcanic rock are of the same origin. The trac
作者
陈柏林
祁万修
崔玲玲
陈正乐
刘兵
赵雷
蒋荣宝
韩凤彬
李丽
刘荣
CHEN Bailin QI Wanxiu CUI Lingling CHEN Zhengle LIU Bing ZHAO Lei JIANG Rongbao HAN Fengbin LI Li LIU Rong(） Institute of Geomechanics , Chinese Academy of Geological Sciences, Beij ing , 100081 ） No. 1 Geological Survey Party, Xinjiang Bureau of Geology and Mineral Eccploration and Mining, Urumqi, 830011)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2017年第8期1818-1835,共18页
Acta Geologica Sinica
基金
"十二.五"
"十一.五"国家科技支撑计划重点项目(编号:2011BAB06B08-04
2006BAB07B02-04)
地质矿产调查专项(编号:1212011085043
DD20160053)的资助成果
关键词
火山成因块状硫化物矿床
形成时代
岛弧成矿构造环境
喀腊达坂铅锌矿床
阿尔金北缘
volcanogenic massive sulfide type（VMS）
metallogenic age
island-arc metallogenic tectonicsetting
Kaladawan Pb-Zn deposit
northern margin of Altun Mountains.
