Geochemical characteristics of trace elements and carbon isotopes in Taiyuan Formation: a case study of Huainan Coalfield

Abstract

This paper reports systematically the redox sensitive elements (Mo, V, Cd, Cr, U and Th) and carbon and oxygen isotope data of the Late Carboniferous Taiyuan Formation limestone in the Huainan Coalfield in the southern margin of North China Platform, combined with the observation of limestone slice, and tries to explain the sedimentary environment of each layer of limestone. Through the analysis of the diagenesis of each layer of limestone, except for L7 and L12 limestone, the lithogenesis change of the remaining limestone becomes weak, which generally reflects the geochemical characteristics of the paleosol during sedimentation. There are three negative shifts of δ13C in Taiyuan Formation limestone, which may be related to the enrichment of redox sensitive elements (Cd, Cr, Mo and V) in limestone. In addition, the value of the above redox sensitive elements shows a negative drift. Combining the low V/Cr ratio and high Th/U ratio, it can be concluded that limestone of the Taiyuan Formation is likely to be deposited under an oxidizing condition.