A precise U–Pb age on cassiterite from the Xianghualing tin-polymetallic deposit (Hunan, South China)
A precise U–Pb age on cassiterite from the Xianghualing tin-polymetallic deposit (Hunan, South China)
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DOI：
10.1007/s00126-007-0166-y
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发表时间：
2008-06
影响因子：
4.8
通讯作者：
Shunda Yuan;Jian‐tang Peng;R. Hu;Huimin Li;Nengping Shen;Dongliang Zhang
中科院分区：
文献类型：
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作者：
Shunda Yuan;Jian‐tang Peng;R. Hu;Huimin Li;Nengping Shen;Dongliang Zhang
我们首次报告了华南南岭地区中部香花岭大型锡多金属矿床锡石的精确 U-Pb 同位素数据。结果表明，XF-51样品中的4个分离物的206Pb/238U表观年龄范围相对较窄，为152~157Ma，3个206Pb/238U表观年龄的加权平均值为156±4Ma（MSWD=0.32）。与其他两个锡石样品的分离物没有足够的放射性 Pb 来生成可靠的 206Pb/238U 年龄。上述三个锡石样品中的七个分离物定义了一个严格约束的 238U–206Pb 等时线，对应于 157 ± 6 Ma (MSWD = 34) 的年龄。将 U-Pb 锡石年龄与已发表的该矿床白云母 Ar-Ar 年龄数据以及与该地区锡矿化成因相关的深成体黑云母 K-Ar 年龄数据进行比较，表明锡石 U-Pb 同位素系统是一种潜在的地质年代计。结合该矿床白云母的Ar-Ar测年，我们可以确定香花岭锡多金属矿化的绝对年龄为154-157 Ma。本研究获得的日期与已发表的该地区其他重要矿床的地质年代学结果一致，表明南岭中部地区的大规模钨锡矿化主要发生在 150–161 Ma 期间。
We report the first precise U–Pb isotope data on cassiterite from the large Xianghualing tin-polymetallic deposit in the central Nanling district, South China. The results show that four separates from sample XF-51 have a relatively narrow range of206Pb/238U apparent ages, varying from 152 to 157 Ma, and the three206Pb/238U apparent ages yield a weighted average value of 156 ± 4 Ma (MSWD = 0.32). Separates from two other cassiterite samples do not have sufficient radiogenic Pb to generate a reliable206Pb/238U age. Seven separates from the above three cassiterite samples define a well-constrained238U–206Pb isochron corresponding to an age of 157 ± 6 Ma (MSWD = 34). A comparison of the U–Pb cassiterite ages with published Ar–Ar dates on muscovite from this deposit and K–Ar age data on biotite from the pluton genetically related to the tin mineralization in this area demonstrates that the U–Pb isotope system of cassiterite is a potential geochronometer. Combined with the Ar–Ar dates of muscovite from this deposit, we can constrain the absolute age of tin-polymetallic mineralization in Xianghualing at 154–157 Ma. The dates obtained in this study, consistent with the published geochronological results from other important deposits in this region, reveal that the large-scale tungsten–tin mineralization in the central Nanling region was predominantly emplaced during 150–161 Ma.