Tectonic control on enrichment and metallogenesis of strategic metal elements in coal measures

The accumulation and distribution of strategic metal minerals in coal measures is the comprehensive result of multi-factors, multi-stages and multi-levels, amongst which the tectonic control is an important factor. The tectonic controlling factors of strategic metal enrichment and mineralization in coal measures include tectonic background, tectonic movement, tectono-magmatic activity, etc., which are reflected in the control of the metal mineral carrier (i.e., coal-bearing rock series), the source of metallogenic materials and the initial aggregation of elements and the later migration and recombination. The entire process of formation and evolution of coal-bearing basins is pervasively influenced by the control of tectonic processes on the enrichment and mineralization of strategic metals, as indicated by coal-measure mineral product source correlation, coupled mineralization, and coexistence in the same basin. The tectonic movement before coal-accumulating period established the structural pattern of coal basin basement, and the subsidence and uplift provided the place of coal-accumulating and the source area of coal measures, which thereby determines the material basis of coal measures and its strategic metal elements. During the coal-accumulating period, the tectonism is mainly reflected in the main forms of basin-mountain coupling behavior, syndepositional structure activity, magmatic activity, etc. Through the influence of coal-accumulating source-to-sink system, the lithofacies-paleogeography and coal-accumulating environment, the types of peat swamp and geochemistry conditions, tectonic process determines the migration and primary accumulation of metallogenic materials in the peatization and diagenesis stages. The tectonic-thermal evolution after the coal-accumulating period has different effects on the migration and reorganization of metal elements, reflecting in the tectonic subsidence heating and magma thermal effect, the tectonic framework and ore-bearing hydrothermal activity, the stress-strain ore-controlling mechanism. Besides, the positioning of coalfield structures determines the mineral deposit resources condition. The study on the tectonic control over the enrichment and metallogenesis of strategic metal elements in coal measures should focus on the following four aspects: the tectonic framework and evolution associated with the sedimentary filling of coal basin, the characteristics of faults as migration channels of ore-bearing fluids, the influence of magmatic activity in different periods and the tectonic physical chemistry effect induced from stress and strain relationship.