高山峡谷区地球化学普查采样点协同优化布设与现场微调方法

    Synergistic optimization and on-site fine-tuning methods for sampling point arrangement for geochemical survey in an alpine gorge area, Southwest China

    • 摘要: 水系沉积物测量因其简便高效、成本低廉且找矿效果显著,是区域地质调查中应用最广泛的方法,在西南水系发育区尤具潜力。样品采集的质量直接决定地球化学勘查数据的代表性和准确性。针对高山峡谷区采样点布设中存在的次级水系控制不足、高能区粗粒碎屑遗漏及人为污染干扰等问题,本研究以云南省会泽县翻身村地区1∶5万水系沉积物测量为例,创新性地提出“协同优化—现场微调法”的优化策略,通过整合双级动态网格(1 km×1 km基础网格+500 m加密网格)、河道走向动态偏移(50~100 m)及污染缓冲区(200 m)预设等关键技术并应用于野外工作中,结果表明:相较传统固定网格方法,三级支流覆盖率显著提高至72%,粗粒碎屑(>2 mm)捕获率达82%,人为伪异常发生率降至5%,综合成本增幅控制在12%。该方法有效提升了复杂地貌区采样数据的可靠性与异常圈定精度,为西南高山峡谷区地球化学勘查提供了优化方案。

       

      Abstract: Stream sediment survey is the most widely applied method in regional geological surveys due to its simplicity, efficiency, low cost, and proven effectiveness in mineral exploration. This method shows promising application potential in Southwest China, characterized by well-developed hydrographic nets. Sampling quality directly determines the representativeness and accuracy of geochemical exploration data. However, sampling point arrangements in alpine gorge areas remain challenged by insufficient coverage of lower-order streams, omission of coarse-grained clastics in high-energy zones, and interference from human-induced contamination. To address these challenges, this study innovatively proposed an optimization strategy combining synergistic optimization and the on-site fine-tuning method for the 1∶50 000 stream sediment survey in the Fanshen Village area, Huize County, Yunnan Province. This strategy integrates critical technologies, including two-level dynamic grids (a 1 km×1 km basic grid and a 500 m infill grid), dynamic channel alignment offset (50 m to 100 m), and pre-set contamination buffer zones (200 m), for fieldwork. The results indicate that compared to traditional fixed-grid methods, the optimization strategy achieved a significantly increased coverage rate of 72% for tertiary tributaries, a capture rate of 82 % for coarse-grained clastics (>2 mm), and a reduced occurrence rate of 5% for human-induced pseudo-anomalies, with the overall cost increase controlled within 12%. Overall, the optimization strategy can effectively enhance the reliability of sampling data and the accuracy of anomaly delineation in complex topographic areas, providing an optimized solution for geochemical surveys in alpine gorge areas, Southwest China.

       

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