新疆喀炼铁厂铜铅锌矿床砂岩地球化学特征及其构造背景判别

新疆喀炼铁厂铜铅锌矿床位于萨热克铜多金属矿区与乌拉根铅锌矿区的过渡带,主要赋矿层位为克孜勒苏群第五岩性段,由岩屑砂岩、含砾砂岩、砂砾岩等组成。稀土元素以轻稀土元素富集,重稀土元素相对亏损,Eu弱负异常为特征。砂岩中Sr、Pb、U、Cu、Zn、Co、Y元素相对于上地壳富集,Sc、V、Cr、Ni元素相对于上地壳亏损。砂岩化学蚀变指数CIA值为50. 84~55. 37,平均值为52. 90,反映了寒冷、干燥的气候下低等的化学风化程度。砂岩的成分变异指数ICV值为0. 98~7. 40,平均值为2. 73,表明该区克孜勒苏群砂岩为初次旋回的沉积物。其物源区主要为北侧的吉根-萨瓦亚尔酸性火山岩区和东侧的中元古界长城系基底地层,具有多源区物源沉积特征。结合区域构造演化研究表明,喀炼铁厂铜铅锌矿区位于盆-山-原构造耦合部位,受吉根-萨瓦亚尔顿大陆岛弧造山带、苏鲁铁列克垂向基底隆起构造带、帕米尔高原北缘弧形前陆冲断褶皱带联合控制。

Geochemical characteristics and determination of tectonic setting of sandstones from the Cu-Pb-Zn deposits in Kaliantiechang area, Xinjiang

The Cu-Pb-Zn deposit in Kaliantiechang area is located in the transitional zone of Sareke Copper polymetallic mine and Wulagen lead-zinc mine in Xinjiang province. The main ore-bearing horizon is the fifth lithologic section of the Kezilesu group,which is mainly composed of lithic sandstone,pebbly sandstone,glutenite,etc.The REE distribution patterns are uniform,with LREE enrichment,flat HREE,and moderate negative Eu anomalies. Chemical index of alteration CIA( CIA = 50.84 ~ 55.37,average 52.90) of the sandstones displayed that they have experienced low grade of chemical weathering and alteration under arid paleoclimate condition.Component index of variation ICV( ICV = 0.98 ~ 7.40,average 2.73) of the sandstones displayed that the sandstone of Kezilesu group is the sediment of the first cycle. The source rocks were mainly composed of the northern Jigen-Sawayaerdun acidic volcanic province and the eastern middle Proterozoic Changcheng basement stratum formatiom,which have the characteristics of multi-source source deposition. The tectonic setting of sandstone formation is passive continental margin and continental island arc tectonic setting. Combined with regional tectonic evolution,suggested that the Cu-Pb-Zn deposit in Kaliantiechang area is located in Basin-mountain-plateau structural coupling position,are jointly controlled by the continental island arc orogenic belt in the Jigen-Sawayaerdun,the vertical basement uplift belt in Sulutielieke and the foreland fold-and-thrust belt in the north edge of Pamirs.