东天山卡拉塔格铜多金属矿集区黄铁矿化(次)流纹岩年代学、地球化学特征及其对成矿的潜在意义  

Zircon U-Pb geochronological,geochemical characteristics and potential mineralization significance of the rhyolite in Kalatage copper polymetallic ore cluster area,eastern Tianshan

作　　者：龙灵利[1] 王京彬[1] 王玉往[1] 方同辉[2] 毛启贵[1] 高一菡[1] 赵路通[1] 高立明 

机构地区：[1]北京矿产地质研究院,北京100012 [2]有色金属矿产地质调查中心,北京100012 [3]中材地质工程勘查研究院有限公司,北京100102

出　　处：《岩石学报》2017年第2期367-384,共18页Acta Petrologica Sinica

基　　金：国家重点基础研究发展计划项目(2014CB440803;2007CB411304);国家自然科学基金项目(41202064;41372102;41572077)联合资助

摘　　要：卡拉塔格矿集区位于东天山吐哈盆地南缘大南湖岛弧带中,区内普遍发育黄铁矿化流纹岩类。该类岩石主要由(次)流纹岩、少量流纹质火山角砾熔岩和英安岩组成,均为偏铝质钙碱性岩石,具高硅特征(Si O2=69.51%~95.81%);稀土总量不高(ΣREE=9.53×10^(-6)~86.40×10^(-6)),轻重稀土分异较弱((La/Yb)N=0.41~29.4),铕多具负异常(δEu=0.29~1.91),显示轻稀土略富集的右倾型配分模式的地球化学特征;轻微富集Rb、Ba、K等大离子元素,明显亏损Nb、Ta、Sr、P、Ti,表现出弧岩浆的特征;正的εNd(t)值(+2.98^+10.61)、分布范围较广的(87Sr/86Sr)i(0.703053~0.712568)值表明岩浆源区主要来自地幔,且有地壳物质的混染。获得流纹质火山角砾熔岩和次流纹岩SHRIMP锆石U-Pb年龄分别为439.9±4.8Ma、439±7Ma。综合研究表明,该岩类可能为早志留世古亚洲洋向北俯冲至准噶尔板块之下形成的火山-次火山岩。黄铁矿化(次)流纹岩与红石-梅岭热液脉状矿床存在成因联系,该岩类同源深成岩体可能为红石-梅岭脉状矿床的成矿地质体。同时,它们是卡拉塔格矿集区重要的找矿标志之一,且具有一定的普遍性。Kalatage ore cluster area is located in Dananhu island arc belt on southern margin of Tuha Basin,eastern Tianshan,and pyritized rhyolite was generally developed in cluster area. This type of rock is composed of rhyolite,a small amount rhyrolitic volcanic breccia lavas and dacite. They are all metaluminous and calc-alkaline series,characterized by high silica（ SiO_2= 69. 51% ~95. 81%）; the total REE content of them is relatively low（ ΣREE = 9. 53 × 10^（-6）~ 86. 40 × 10^（-6））,REE fractionation is weak（（ La/Yb）N= 0. 41 ~ 29. 4）,together with negative Eu anomaly（ δEu = 0. 29 ~ 1. 91）,and their REE distribution patterns are of the rightinclined type with LREE slightly enriched; they are slightly enriched large-ion lithophile element Rb,Ba,K and obviously depleted Nb,Ta,Sr,P,Ti,showing the geochemical characteristics of island arc magmatic rocks. The positive εNd（ t） values（ ＋ 2. 98 ~ ＋10. 61） and a wide range of initial87Sr/86 Sr values（ 0. 703053 ~ 0. 712568） of the rhyolites were proposed that its original magma came from the mantle and mixed with crustal material. The SHRIMP zircon U-Pb ages of 439. 9 ± 4. 8Ma for the rhyrolitic volcanic breccia lava and 439 ± 7Ma for the rhyolite were obtained. Comprehensive research on the chronological,geological and geochemical characteristics of the rhyolites,shows that they are the volcanic and sub-volcanic rock formed by the subduction of Paleo-Asian ocean northwards beneath the Junngar plate in Early Silurian. The pyritization rhyolite has the genetic relationship with the deposits of Kalatage ore cluster area,especially with the Hongshi-Meiling epithermal deposit,and the cogenetic rhyolitic pluton may be the oreforming geological bodies of Hongshi-Meiling vein-type deposits. They＇re one of the important prospecting indicators of Kalatage ore cluster area,and has certain universality.

关 键 词：新疆 东天山 卡拉塔格 (次)流纹岩 地球化学 SHRIMP锆石U-PB年龄 成矿 

分 类 号：P618.51[天文地球—矿床学]