新疆东准噶尔贝勒库都克锡矿带锡成矿的40Ar-39Ar年龄  

^(40)Ar-^(39)Ar age of tin mineralization in the Beilekuduk tin metallogenic belt,East Junggar, Xinjiang (NW China)

作　　者：唐红峰[1] 苏玉平[1,2] 邱华[3] 韩宇捷[1,2] 

机构地区：[1]中国科学院地球化学研究所,地球深部物质与流体作用地球化学研究室,贵阳550002 [2]中国科学院研究生院 [3]中国科学院广州地球化学研究所,同位素年代学和地球化学重点实验室

出　　处：《岩石学报》2009年第6期1303-1309,共7页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(40772044)资助.

摘　　要：位于新疆东准噶尔的贝勒库都克锡矿带是我国北方地区首次发现具独立锡矿床的锡成矿带。该成矿带自东向西发育萨惹什克、贝勒库都克、干粱子、卡姆斯特4个独立锡矿床。它们在主要矿石类型、脉石矿物组成上表现为两类。萨惹什克锡矿属于石英型,占优势的脉石矿物是石英,其次有长石,而白云母很不发育。其它3个锡矿则以云英岩型为特征,主要脉石矿物是石英和长石,次要矿物有白云母。本文报道了我们对发育白云母的卡姆斯特、干梁子、贝勒库都克锡矿床开展矿石^(10)Ar-^(39)Ar同位素定年的结果。3件与锡石平衡共生的白云母有很平坦的年龄谱,其^(40)Ar/^(36)Ar-^(39)Ar/^(36)Ar正等时线年龄与各自的坪年龄很一致,年龄值范围是305～315Ma。这些结果和我们已报道的萨惹什克锡矿的Re-Os等时线年龄一起,确定了全部4个锡矿床的成矿年龄,并证实它们构成一个锡成矿带。此外,锡矿石与花岗岩围岩年龄的一致性表明了研究区锡成矿与花岗岩浆作用间很可能存在成因关系。The Beilekuduk tin metallogenic belt in the eastern Junggar of Xinjiang is the first one discovered in northern China with four independent tin deposits, from east to west, named Sareshik, Beilekuduk, Ganliangzi, and Kamst, respectively. These tin deposits can be divided into two groups in terms of their ore type and gangue mineral compositions. The ores in Sareshik tin deposit are quartz type, and the gangue minerals are predominately composed of quartz, with minor feldspar, but almost no muscovite. Whereas the other three tin deposits are greisen type, and mainly composed of quartz and feldspar, with minor muscovite. In this paper, the ^(40)Ar-^(39)Ar dating results are reported for muscovites from Kamst, Ganliangzi, Beilekuduk tin deposits. The three samples of muscovite in equilibrium with cassiterite yield very flat age spectra. The ^(40)Ar/^(36) Ar-^(39) Ar/^(36) Ar normal isochron ages are well concordant with their corresponding plateau ages, ranging from 305 to 315Ma. These results, together with the Re-Os isochron age of the Sareshik tin deposit we previously reported well constrain the mineralization ages for the four tin deposits, and hence confirm that they certainly belong to the same tin metallogenic belt. Moreover, the coincident ages of the tin ores and their granite wallrocks indicate the most likely genetic relationship between tin mineralization and granitic magmatism in the studied region.

关 键 词：~40 Ar-~39 AR年龄 锡成矿 贝勒库都克锡矿带 东准噶尔 新疆 

分 类 号：P618.44[天文地球—矿床学] P597.3[天文地球—地质学]