This paper is the result of mineral exploration engineering.
Objective The Upper Carboniferous Benxi Formation in the Lüliang area, Shanxi Province is rich in sedimentary lithium resources. However, the relationship between lithium resource enrichment and source rocks, as well as sedimentary processes, is unclear.
Methods Based on geological surveys of field outcrops, this study comprehensively analyzes the heavy mineral characteristics of the Upper Carboniferous Benxi Formation in the Lüliang area. Tourmaline electron probe microanalysis and detrital zircon U−Pb dating were used to determine the source rocks. The results of detailed zircon trace element were performed to infer the tectonic setting of Benxi Formation. In combination with regional data, provenance analysis, and heavy mineral image interpreting, we elucidate the material sources of the Benxi Formation and explore the relationship between lithium enrichment and sedimentary processes such as weathering, transportation, and sedimentary recycling. Then we further determine the origin of lithium enrichment in the Benxi Formation.
Results The results indicate that the Benxi Formation is mainly composed of fine-grained sediments. The tourmaline electron probe microanalysis results show that the source rocks are mainly derived from granitoids and their associated pegmatites and aplites, metapelites and metapsammites. Detrital zircon dating results suggests that the parent rocks are mainly felsic magmatic rocks. The comprehensive analysis shows that the provenance of Benxi Formation mainly came from felsic magmatic, metasedimentary rocks, and carbonate of Inner Mongolia Paleo-Uplift and North China Craton. The sediments of Benxi Formation formed in the retroarc foreland basin.
Conclusions The enrichment of sedimentary lithium resources is a complex process. The source rocks provide the material for lithium enrichment, and multiple factors such as weathering, sediment recycling, and diagenesis control the enrichment of lithium resources.
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