Abstract:
By virtue of the organic mineralization geochemistry research, this article validates that the deposits in Hunan and Guizhou have undergone epigenetic structural hydrothermal metamorphism events. According to the geo-history in Zunyi of Guizhou province, oil has been produced in this region, thus we can acknowledge that the thermal maturation process of the organic matter was accompanied by the processes of pyrolysis, fluid migration, hydrocarbon production, gas formation, exhausting, and oil formation. The contents of pristine(Pr) and the phytene(Ph) in the phosphorite are the highest, which are 3.33% and 5.84% respectively, indicating the most remarkable biogenesis. Because the enrichment of PGE elements is related to organic matter, there is large discrepancy between the maturity of different thermal evolutions as well as their corresponding thermal evolution history. Consequently, it is believed that the aromatic structure effect of the organic matter will lead to the abnormal enrichment of the PGE metal elements. Similar to other oilfields, the study area boasts the same typical characteristics of high saturation hydrocarbon, low aromatic hydrocarbon, high non-hydrocarbon and low bitumen, indicating that the ore bed is oil bitumen. In addition, the methyl phenanthrene rate and dia-methyl phenanthrene rate in the sample from Zunyi of Guizhou is the highest, while the dia-methyl phenanthrene rate as 1.36 of the metal enrichment bed in Ganziping of Zhangjiajie, Hunan province is also the highest, confirming that both oilfields are of highest maturity.