Fluid mixing leads to main-stage cassiterite precipitation at the Xiling Sn polymetallic deposit, SE China: evidence from fluid inclusions and multiple stable isotopes (H-O-S)
Fluid mixing leads to main-stage cassiterite precipitation at the Xiling Sn polymetallic deposit, SE China: evidence from fluid inclusions and multiple stable isotopes (H-O-S)
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流体混合导致中国东南部西岭锡多金属矿床主期锡石沉淀：来自流体包裹体和多种稳定同位素（H-O-S）的证据
DOI：
10.1007/s00126-019-00933-0
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发表时间：
2020
影响因子：
4.8
通讯作者：
Ryan Mathur
中科院分区：
文献类型：
--
作者：
Peng Liu;Jingwen Mao;Wei Jian;Ryan Mathur
粤东西岭锡矿床由凤地山锡矿和扫洲地锡铅锌矿块组成，长期以来被认为是与锡多金属成矿有关的火山-次火山体系。在这里，我们提供了不同矿期的流体包裹体显微测温数据和热液矿物的H-O-S同位素数据来约束西岭矿床的成因。第一阶段的流体包裹体的温度范围为约 340 至 420 °C，盐度为约 15 至 17 wt% NaCl 当量，而阶段 II 至 V 的流体包裹体的均一温度范围为约 150 至 320 °C，盐度范围为约 1 至 6 wt% 当量。石英和锡石的氧、氢同位素组成（δDfluid−65‰；δ18Ofluid3.6～6.3‰）表明，I期成矿流体具有明显的岩浆特征，而II期至IV期的成矿流体（δDfluid−80～−49‰；δ18Ofluid−3.7～2.5‰）则表现出大气与成矿流体的混合特征。岩浆液。此外，封地山矿块硫化物的δ34S值范围较窄，为0.6~2.5‰，平均值接近0‰，与岩浆硫源一致。相比之下，骚周地矿块矿石矿物的 δ34S 值范围为 3.4 至 11.5‰，表明涉及沉积硫源。此外，前期地质年代学研究表明，火山-次火山岩围岩年龄为160~170 Ma，锡多金属矿化年龄为145 Ma左右。我们的数据支持隐藏的花岗岩侵入岩浆盐水与大气水混合的模型。 S同位素数据和观测到的流体系统温度梯度表明，Sn矿化发育在矿系的中部，而Sn-Pb-Zn和Pb-Zn矿化发生在远端。这一发现可能对该地区的勘探产生重要影响。
The Xiling Sn deposit in eastern Guangdong Province comprises the Fengdishan Sn and the Saozhoudi Sn–Pb–Zn ore blocks and has long been regarded as a volcanic–subvolcanic system related to Sn polymetallic mineralization. Here, we present fluid inclusion microthermometric data from different ore stages and H–O–S isotope data of hydrothermal minerals to constrain the genesis of the Xiling deposit. Fluid inclusions from stage I haveThvalues from ~ 340 to 420 °C and salinities from ~ 15 to 17 wt% NaCl equivalent, while homogenization temperatures of fluid inclusions from stages II to V range from ~ 150 to 320 °C, and salinities range between ~ 1 and 6 wt% equivalent. The oxygen and hydrogen isotopic composition of quartz and cassiterite (δDfluid− 65‰; δ18Ofluid3.6 to 6.3‰) suggest that the ore-forming fluids from stage I have a distinct magmatic signature, whereas those from stage II through stage IV (δDfluidfrom − 80 to − 49‰; δ18Ofluidfrom − 3.7 to 2.5‰) show characteristics of mixing between meteoric and magmatic fluids. Moreover, δ34S values for sulfides from the Fengdishan ore block have a narrow range of 0.6 to 2.5‰ with a mean close to 0‰, consistent with a magmatic sulfur source. By contrast, δ34S values for ore minerals from the Saozhoudi ore block range from 3.4 to 11.5‰, suggesting involvement of a sedimentary sulfur source. In addition, a previous geochronological study has shown that the volcanic–subvolcanic host rocks have an age of 160–170 Ma, while the Sn polymetallic mineralization has an age of about 145 Ma. Our data support a model of mixing of magmatic brine from a hidden granitic intrusion with meteoric water. The S isotope data and the observed temperature gradient of the fluid system suggest that the Sn mineralization is developed in the central part of the ore system, while the Sn–Pb–Zn and Pb–Zn mineralization occurs in the distal part. This finding might have important implications for exploration in the region.