Analysis on the Paleoenvironment of Cuijiagou Coal Mine in Jurassic Coalfield,Northern Shaanxi
In order to ascertain the palaeoclimate characteristics,paleo-water salinity and paleo-oxidation-reduction degree of the coal seams in Yan'an Formation in the study area,elemental testing and analysis were performed on the Yan'an Formation coal,and element geochemistry was used to restore the ancient environment,which is one of the commonly used methods.According to data analysis,the Sr/Ba ratio,the content of B element and the content of Sr in the three coal seams have the same vertical trend of increasing first and then decreasing.The Sr/Ba ratio is more than 1.0,These indicate the high salinity of the ancient water bodies,mainly in the salt-brackish water environment.The vertical variation of the parameters such as Sr/Ba ratio,Mg/Ca ratio and the content of Na element reflect that the No.1 coal seam deposited in relatively humid environment,the No.2 coal seam deposited tended to dry Climate,and No.3 coal seam deposited in humid climate.They experienced a humid climate-partial dry climate-relatively humid climate evolution.The vertical variation of V/Cr ratio,V/(V+Ni)ratio,Cu/Zn ratio,the content of V element and other parameters indicate that the ancient water bodies experienced a reduction-partial oxidation-partial reduction but mainly oxygen deficiency environment during the deposition history.
element geochemistrypaleosalinitypaleoclimatepaleo oxidation-reduction degreeCuijiagou coal mine
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NSTL
万方数据
