Geochemistry of Elements in the Coal Seams of the Xishanyao Formation from Gashunwusan Mine, Xinjiang, Northwest China

Abstract

The samples from Xishanyao Formation in Gashunwusan Mine were analysed by inductively coupled plasma mass-spectrometry (ICP-MS), X-Ray fluorimetry (XRF) and other techniques. Through the use of the above techniques, we researched characteristics and modes of occurrence of the trace elements. According to content and ratios of trace elements, we discussed coal-forming environments of the research area. The results show that Co, Ga, Sr, and Ba were slightly enriched in different coal seams in Xishanyao Formation in Gashunwusan Mine and total contents of trace elements were lower than the average values of Chinese and world coal. The common elements mainly contain CaO, SiO2, Al2O3 and Fe2O3. The contents of above elements were low. Contents of CaO and MgO were higher than those in Chinese coal and US coal, while other elements were relatively depleted. There was a positive correlation between most of the trace elements and ash content. Modes of occurrence of most of trace elements were connected with inorganic mineral, which were effected considerably by terrestrial material. The values of Sr/Ba, V/Ni, and V/Zn revealed that the sedimentary type of Jurassic coal seam in Gashunwusan Mine was the typical interior phase of lakes. The value Ni/Co revealed that the redox environment of coal-forming swamp was relatively weak.