Zircon (U-Th)/He thermochronometric constraints on the mineralization of the giant Xikuangshan Sb deposit in central Hunan, South China
Zircon (U-Th)/He thermochronometric constraints on the mineralization of the giant Xikuangshan Sb deposit in central Hunan, South China
复制标题
湘中西矿山巨型锑矿床锆石(U-Th)/He热年代学约束
DOI：
10.1007/s00126-019-00906-3
复制
发表时间：
2020-06-01
影响因子：
4.8
通讯作者：
Mi, Xifeng
中科院分区：
文献类型：
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作者：
Fu, Shanling;Hu, Ruizhong;Mi, Xifeng
中国南方湖南中部的锡矿山锑矿是世界上最大的锑矿床，提供了世界上50%以上的锑，总锑金属储量约为250万吨。然而，由于缺乏合适的矿物进行可靠的辐射定年，该矿床的年龄仍未得到很好的限制，这阻碍了普遍接受的成矿成因模型的产生。由于流体包裹体数据表明锡矿山矿床成矿流体温度高达360℃，本文选择闭合温度为160 ~ 200℃的锆石(U-Th)/He热时法来厘定Sb成矿年龄。锡矿山矿床蚀变寄主岩碎屑锆石的年龄分别为156 ~ 117 Ma和97 ~ 86 Ma。较老的年龄群（156 ~ 117 Ma）与前人对热液方解石（156 ~ 124 Ma）的Sm-Nd定年结果吻合较好，可能代表了锡矿山锑矿主成矿期，而较年轻的锆石(U-Th)/He年龄可能是由于深部侵入体的远端作用导致锆石中He的部分损失所致。研究结果表明，蚀变寄主岩中锆石的(U-Th)/He定年可用于限定低温成矿时间。
The Xikuangshan Sb deposit in central Hunan, South China is the largest Sb deposit in the world, which has supplied more than 50% of the world's Sb and with total Sb metal reserves of about 2.5 Mt. However, the age of this deposit is still not well constrained due to a lack of suitable minerals for reliable radiometric dating, which hampered the generation of a generally accepted genetic model of mineralization. Since the fluid-inclusion data suggest that the temperature of ore-forming fluids in the Xikuangshan deposit is up to 360 degrees C, zircon (U-Th)/He thermochronometry with the closure temperature of 160-200 degrees C was chosen here to elucidate the age of Sb mineralization. Detrital zircons in the altered host rocks from the Xikuangshan deposit yielded two (U-Th)/He age populations of 156-117 and 97-86 Ma. The older age population (156-117 Ma), which is well in accordance with previous Sm-Nd dating on hydrothermal calcite (156-124 Ma), probably represents the timing of main-stage Sb mineralization in the Xikuangshan Sb deposit, while the younger zircon (U-Th)/He ages may result from partial loss of He in zircon caused by the distal effect of deep-seated intrusions beneath the deposit. This study demonstrates that the (U-Th)/He dating of zircon in altered host rocks can be viable for constraining the timing of low-temperature mineralization.