西藏莎马达地区1∶5万水系沉积物测量地球化学特征及找矿方向

    Geochemical characteristics and prospecting directions of the Shamada area in Xizang based on a 1∶50,000 stream sediment survey

    • 摘要: 西藏莎马达地区地处特提斯喜马拉雅构造域东段,隶属康马—隆子地层分区,为青藏高原最具特色和重要的金(锑)成矿带。近年来康马穹窿周边发现多处锑、金及稀有金属矿床(点),区域成矿条件优越,找矿前景良好。为进一步指导区内锑、金及稀有金属矿产勘查工作,本次工作在康马县莎马达地区开展1∶5万水系沉积物测量,通过样品采集与测试数据综合处理,编制完成 Sb、Au 等17种单元素异常图及综合异常图;结合区域地质背景,共圈定综合异常8处。通过分析元素组合、富集系数及变异系数等地球化学特征,并结合区域地质背景及成矿条件,明确区内主成矿元素以Sb、Au、As、W等为主;主要赋矿层位为白定浦组(P3b)与吕村组(T1-2lc)接触界面,拆离断层及NW向构造为区内重要控矿构造。经对HS-2号综合异常开展查证工作,发现多处矿化线索。本次调查工作为后续康马穹窿周围矿产勘查部署及找矿方向提供了重要依据与技术思路。

       

      Abstract: The Shamada area in Xizang, located in the eastern segment of the Tethyan-Himalayan tectonic domain, is part of the Kangma-Longzi stratigraphic subregion, representing the most distinctive and significant gold (antimony) metallogenic belt on the Qinghai-Tibet Plateau. In recent years, multiple antimony, gold, and rare metal deposits (ore occurrences) have been discovered in the periphery of the Kangma dome, suggesting superior regional metallogenic conditions and promising prospecting potential. To provide further guidance for the exploration of antimony (Sb), gold (Au), and rare metals in the study area, this study conducted a 1∶50,000 stream sediment survey. Through sample collection and comprehensive test data processing, this study plotted single-element anomaly maps of 17 elements (including Sb and Au) and integrated anomaly maps. In combination with the regional geological setting, eight composite anomalies were delineated in total. The analytical results of geochemical characteristics such as element associations, enrichment coefficients, and coefficients of variation, together with regional geological setting and metallogenic conditions, reveal that primary ore-forming elements in the Shamada area include Sb, Au, arsenic (As), and tungsten (W). Furthermore, the ore-hosted horizons are dominated by the contact interface between the Baidingpu (P3b) and the Lvcun (T1-2lc) formations, and important ore-controlling structures in the study area include detachment faults and NW-trending structures. The verification of the HS-2 composite anomaly reveals multiple clues about mineralization. Overall, this study provides a critical basis and technical approach for subsequent mineral exploration deployment and ore prospecting around the Kangma dome.

       

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