东天山卡拉塔格早古生代红海块状硫化物矿床精确定年及其地质意义

Geochronology studies of the Early Paleozoic Honghai massive sulfide deposits and its geological significance in Kalatage area,eastern Tianshan Mountain

东天山卡拉塔格矿带红海块状硫化物Cu-Zn矿床产于卡拉塔格海相火山岩建造中,矿层主要与两个岩性段的火山-碎屑岩地层有关:(1)盖层为中性-酸性火山岩、火山角砾岩、凝灰岩,夹凝灰质砂岩;(2)赋矿层位主要由中基性-中酸性火山角砾岩、凝灰角砾岩、凝灰岩和沉凝灰岩组成。高精度的锆石离子探针U-Pb同位素定年获得矿体上盘围岩底部酸性火山岩的年龄为416.3±5.9Ma,为成矿时代的上限年龄;K-Ar同位素定年获得矿体下盘强绢云母化蚀变围岩年龄为424±7Ma,记录了最晚一期成矿热液活动的时代。同位素年代学研究显示,卡拉塔格地区在早古生代末期存在一期铜多金属成矿作用,这个认识不仅为吐哈盆地南缘古生代火山岩地层的时代划分提供了年代学限制,而且扩大了卡拉塔格地区和区域找矿空间。

The Honghai massive sulfide Cu-Zn deposit found in the Kalatage volcanic and volcanic-clastics belt in the eastern Tianshan Mountains. The drill cores studies indicate this volcanic and volcanic-clastics buildings are composed by two group of stratums:(1) overlain layers made up of intermediate and felsic volcanic rocks,volcanic breccias,tuff and interlayer tuff sandstone; (2) host-layers mainly composed of massive Cu-Zn sulfide Cu-Zn ore-body,basics,intermediate and felsic volcanic breccias,tuff breccias,tuff and sedimentary tuff. The sample for zircon U-Pb dating was collected at the button of overlain layers,and the sample for K-Ar dating was collected in the intensively altered mineralization zone. Zircon U-Pb dating get the crystallization age is 416.3±5.9Ma for the felsic volcanic rocks,which limit mineralization age. The K-Ar age is 424±7Ma for the sericitized rocks,which recorded the latest mineralization stage. The geochronology studies indicates the Honghai Cu-Zn deposit is an Early Paleozoic deposits,constrict the age of the lower volcanics in the Kalatage area,and also extend the prospecting potential space of the Kalatage and the eastern Tianshan Mountain areas.