Dizhi lixue xuebao (Feb 2024)
Theoretical innovation and applications of ore-field tectonic lithofacies mapping
Abstract
Objective In the matter of material architecture, the diagenetic-metallogenic system may be classified into lithofacies of root-feeders (metallogenic material feeders), lithofacies of structural channel (migration of diagenetic-metallogenic material), lithofacies of closed-reservoir space (unloading-enriching room of diagenetic-metallogenic material), and lithofacies of surrounding rock alteration (water–fluid–rock system of diagenetic-metallogenic material). Ore-field tectonic lithofacies mapping and detailed analysis of the formation mechanism of different types of tectonic lithofacies aid in identifying and delineating in-situ diagenetic-metallogenic systems at the scale of ore clusters and ore fields. These approaches also reveal the formation mechanisms of resources, energy, and minerals, marking it as an innovative direction in ore-field structure and prospecting prediction. In order to promote and deepen the research and understanding of tectonic lithofacies and prospecting prediction in ore fields, this article focused on the lithofacies establishment and modeling predictions on the mineralization-alteration-tectonics-lithofacies, discussing and exploring eight important types of mineralization-alteration-tectonics-lithofacies models and their formation mechanisms domestically and internationally. Methods The article carried out ore field tectonic lithofacies mapping and detailed analysis of the formation mechanism of different types of tectonic lithofacies in order to recognize and delineate in situ diagenetic-metallogenic systems at the scale of ore clusters and ore fields. Results Eight models and formation mechanisms for the mineralization-alteration-tectonics-lithofacies at the scale of ore-field tectonic lithofacies were discussed in this study. The IOCG-type ore field in the Copiapo area of Chile is controlled by the main arc belt, arc-related basins, magmatic superimposing and basin–deformation style. However, the SSC-type Cu deposit and the IOCG-type ore field in the Dongchuan area of Yunnan in southwestern China are located at the marginal rift basin with different styles of basin deformation and reworked by the magmatic superimposing tectonic system. The Jia–Cha epithermal Au-Ag-Pb-Zn ore-field in Inner Mongolia of northern China is dominated by volcanic lake-basin, volcanic dome structure, facies-type of volcanic rocks, and volcanic hydrothermal crypto-explosive breccias, whereas porphyry Cu-Mo-Au and epithermal Au-Cu ore-fields in the South Gebi area of Mongolia are formed in the Devonian–Carboniferous plutonic magmatic arc. The Sedex-type Ag-Cu-Pb-Zn-Ba-Fe ore-field in the Qinling orogeny of central China is shaped by the three-order sub-basin, syngenesis fault, and facies of hydrothermal sedimentary rock in the marginal pull-apart basin. However, gold and Au-Mo-polymetallic ore fields are dominated by different scales of the brittle-ductile shear zones in the orogenic belt. Migrations of the ore-reservoir-forming matters for metallic ore field and gas field are derived from the Jurassic coal-measure hydrocarbon-metal-bearing source rocks in the western Tarim of basin-mountain-plateau mosaic structure in western China. The Wulagen glutenite-type celesite-Pb-Zn ore field located at the piedmont compression to extension conversion basin is coupled by the pneumatogenic plume and superimposed by the piedmont thrust-fold belt. The Sareke glutenite-type Cu-polymetallic ore-field hosted at irony glutenite of the dry-fan facies in the tail-end lake basin is reworked by the hedging-style, base-type thrust fold belt and superimposed by mantle-derived hydrothermal plume. Conclusion Eight models and formation mechanisms for the mineralization-alteration-tectonics-lithofacies at the scale of ore field tectonic lithofacies were discussed in this study based on a review of ore-field tectonics. The tourmaline-rich plume tectonics, magmatic gasbag structure, and compound karsting tectonic lithofacies are three new types of mineralization-alteration-tectonics-lithofacies. Ore-field tectonic paleogeographic unit and formation mechanism of important ore-field tectonic lithofacies, new classification methods and principles of the mineralization-alteration-tectonics-lithofacies and 12 different types of deformational tectonic lithofacies were established in this essay. Significance All achievements in this study have established a new foundation for tectonic lithofacies mapping and ore prediction.
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