Genesis of the Yunlong Sn deposit in the Chongshan Shear Zone, Western Yunnan, SW China

IF 3.4 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Journal of Geochemical Exploration Pub Date : 2025-01-30 DOI:10.1016/j.gexplo.2025.107690

Zhen Jia , Wenchang Li , Jianze Sha , Shiping Li , Fuchuan Chen , Mingguo Deng

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Abstract

The large-scale Yunlong Sn deposit is situated in the western Yunnan, SW China. The NNW- to NS-trending orebodies are hosted in the Cenozoic Chongshan shear zone, parallel with the regional foliation. To clarify the ore genesis at Yunlong, we analyzed the geochronology, trace elements, fluid inclusion and stable isotopes of the mineralized/altered rock samples from the mine. Tin mineralization at Yunlong is divided into three stages: (I) early-ore tourmaline–quartz–cassiterite, (II) main-ore cassiterite–sulfides–quartz, and (III) post-ore quartz-calcite stage. Cassiterite UPb dating reveals that stage I (28.6 ± 1.5 Ma) and II (27.8 ± 1.6 Ma) are coeval with the syn-kinematic leucogranite (35–29 Ma) in the shear zone, indicating a temporal link between the Sn mineralization and the Cenozoic tectono-magmatism. Trace element data (esp. Fe and W) suggest a magmatic origin for stage I and stage IIa mineralization, with those of IIb showing some wallrock input. Fluid inclusion study reveals that the stage I quartz contain a boiling fluid inclusion assemblage with similar homogenization temperature (339–515 °C) and varying salinity (4.3–52.8 wt% NaCl eqv), implying boiling as a vital cassiterite precipitating mechanism. Stage II and III fluid inclusions (mainly featuring V- and L-type) have lower homogenization temperatures (186–349 °C) and salinities (0.6–19.1 wt% NaCl eqv.). Analyses of the ore-related quartz HO isotopes and sulfide S isotopes suggest a predominantly magmatic source for the ore fluid, respectively. In conclusion, we propose that the Yunlong Sn deposit is related to the Cenozoic magmatism and the tectonic shear at Chongshan, and that the Cenozoic Shear Zone in western Yunnan have potential for Sn mineralization.

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来源期刊

Journal of Geochemical Exploration 地学-地球化学与地球物理

CiteScore

7.40

自引率

7.70%

发文量

148

审稿时长

8.1 months

期刊介绍： Journal of Geochemical Exploration is mostly dedicated to publication of original studies in exploration and environmental geochemistry and related topics. Contributions considered of prevalent interest for the journal include researches based on the application of innovative methods to: define the genesis and the evolution of mineral deposits including transfer of elements in large-scale mineralized areas. analyze complex systems at the boundaries between bio-geochemistry, metal transport and mineral accumulation. evaluate effects of historical mining activities on the surface environment. trace pollutant sources and define their fate and transport models in the near-surface and surface environments involving solid, fluid and aerial matrices. assess and quantify natural and technogenic radioactivity in the environment. determine geochemical anomalies and set baseline reference values using compositional data analysis, multivariate statistics and geo-spatial analysis. assess the impacts of anthropogenic contamination on ecosystems and human health at local and regional scale to prioritize and classify risks through deterministic and stochastic approaches. Papers dedicated to the presentation of newly developed methods in analytical geochemistry to be applied in the field or in laboratory are also within the topics of interest for the journal.