Dizhi lixue xuebao (Feb 2024)
Research on weak information extraction methods in the exploration of hidden Carlin-type gold deposits in southwestern Guizhou, China
Abstract
Objective The southwestern Guizhou region is a concentrated distribution area of Carlin-type gold deposits in China, with superior geological conditions for gold mineralization and enormous potential for mineral exploration. However, the shallow gold resources in the region have been largely exhausted, and the exploration work has entered the stage of "exploration in deep and blind areas". Due to the deep burial depth of the ore body, the mineralization information on the surface of hidden gold mines is inevitably very weak or may not even be displayed, making it challenging to obtain deep mineralization information. How to accurately identify and obtain geochemical information related to deep mineralization has become a key factor restricting exploration breakthroughs. Methods Conventional geochemical prospecting methods are susceptible to the influence of surrounding rocks or cover materials, making it difficult to acquire information related to deep mineralization. The formation and emplacement of Carlin-type gold deposits in southwestern Guizhou are mainly controlled by anticlines and fault structures, and the distribution, differentiation, and mineralization of elemental geochemistry are also influenced by tectonic stress. Based on the theory of tectonic geochemistry, this study conducts an in-depth analysis of the geological conditions for gold mineralization and the migration and enrichment patterns of corresponding element combinations in the southwestern Guizhou region. The sampling principles, sampling media, and data selection of weak information extraction in tectonic geochemistry are restricted to a certain extent. Various high permeability conductive shallow structural rock samples are collected to test their ore-forming indicator elements. This method can identify and extract weak information on the formation of deep-hidden ore bodies on the surface. Results Deep mineralization information is related to the shallow and surface through faults and fractures, and the geochemical anomalies in the shallow structural rocks can somewhat reflect the deep mining-induced anomalies. The sampling object for weak information extraction in tectonic geochemistry is tectonic altered rocks, which highlights information related to mineralization and weakens other interference information, thus enabling the extraction of weak geochemical anomalies formed by deep-hidden mineralization on the surface. In the formation process of hydrothermal deposits, the structure is not only a good channel for the migration of ore-forming fluids but also a favorable space for mineral precipitation and enrichment of ore-forming. The element geochemical anomalies obtained from collecting structural rock samples can indicate the ore-forming properties of the corresponding structure, indirectly indicating the ore-forming center and providing a scientific basis for the preliminary positioning prediction and engineering verification of hidden deposits. The weak information extraction method of structural geochemistry has been proven effective in the exploration of hidden Carlin-type gold deposits in southwestern Guizhou. This method can be extended to more exploration practices of hidden deposits in hydrothermal deposits, showing broad application prospects. Conclusion The weak information extraction technology of structural geochemistry is applicable to the exploration of hydrothermal deposits, which can effectively extract weak mineralization information of deep-hidden deposits, help invert the structural control type, infer the approximate occurrence of hidden deposits, select key exploration target areas, and conduct preliminary positioning and prediction of hidden deposits. Significance The research results on identifying and extracting weak geochemical information have specific academic value for enriching the ore-forming theory of Carlin-type gold deposits in southwestern Guizhou. At the same time, this method can effectively delineate and optimize the exploration target areas for hidden hydrothermal mineral deposits, which has positive practical significance for implementing a new round of breakthrough strategic action tasks in mineral exploration.
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