湘中北晚二叠世石煤元素地球化学特征OA北大核心CSTPCD

The Wujiaping Formation of the Late Permian in the central northern regions of Hunan Prov-ince contains a small amount of stone coal with distinct attribute characteristics.In order to reveal the geochemical characteristics of stone coal elements in the north-central regions of Hunan province,four late Permian stone coal samples from north-central regions of Hunan province were collected.The min-eral composition,major element and trace element contents,and the occurrence state of trace elements of stone coal samples were determined and analyzed by X-ray diffractometer,scanning electron micro-scope with energy spectrum,X-ray fluorescence spectrometer,inductively coupled plasma mass spec-trometer and stepwise leaching experiments.The results show that the high ash characteristics of Late Permian coal in the central and northern regions of Hunan are significant,with differences in total sul-fur content.Iron sulfide is the main component,followed by organic sulfur.There are relatively few types of coal minerals,mainly quartz,with a large input of terrestrial debris.The stone coal is highly en-riched in V,Cr,As,Cd,Mo and Sb,with Cd reaching 555 times the abundance of the upper crust.The occurrence characteristics of trace elements in late Permian stone coals are complex,in which the oc-currence states of Ni,Zn,Sr,Mo and Cd are rich,while the occurrence states of Li,V,Cr,Cu,Rb,Zr,Ba,U and REEs are relatively simple.According to the geochemistry characteristics of the late Permian stone coal in central and northern regions of Hunan,it is considered that the stone coal is deposited in the passive continental margin area,receiving the input of terrigenous detritus,and the sedimentary source area is dominated by felsic acid rocks.The sedimentary process of stone coal is strongly influ-enced by seawater,and the relative stable anoxic environment provides conditions for the self-enrich-ment of elements such as V and Mo.