Mechanism and controlling factors of paleoweathering crust Sedimentary-Type titanium deposits in the Central-Eastern North China Craton: A Case study of the Upper Carboniferous Benxi Formation in the Zibo-Zhangqiu area

Titanium, as a critical strategic metal, its resource security is vital to the development of China’s high-tech industries. Paleoweathering crust sedimentary-type rutile titanium mineralization was first discovered in the Upper Carboniferous Benxi Formation in the Zhangdian area of Zibo, central-eastern North China Craton (NCC). However, the types, mineralization mechanisms, controlling factors, and distribution patterns of titanium deposits within the Benxi Formation across this region remain unclear. This study focuses on the Benxi Formation profiles in three areas: Zhangqiu (Jinan), Boshan (Zibo), and Zhangdian (Zibo). A systematic investigation was conducted by integrating multiple methods, including petrography, mineralogy, whole-rock geochemistry, and detrital zircon and rutile U-Pb dating. The results indicate that: Titanium in the Benxi Formation of the study area is mainly composed of TiO 2 , primarily occurring in the forms of anatase and rutile within aluminous mudstones or bauxites. The provenance of titanium is multi-sourced, derived mainly from magmatic and metamorphic rocks of the northern margin of the NCC and the North Qinling Orogenic Belt, as well as Precambrian metamorphic terranes inside the craton. Sedimentary recycling and intense chemical weathering are important factors affecting titanium enrichment, which is synergistically controlled by tectonics, climate, geomorphology, and provenance. Based on the above research, the mineralization process is divided into three stages: “source area formation-ore-hosting space construction”, “ore-forming material transport and weathering leaching”, and “late-stage modification”. A “tectonics-climate-geomorphology-provenance” synergistic mineralization model is established, which clarifies that areas such as shallowly buried aluminous mudstones or bauxites and karst depressions are favorable prospecting targets.