Trace Element Geochemical Characteristics And Geological Significance Of Coal Measures Strata In Huainan Area

The characteristics Sedimentary environmental evolution and sediment provenance was discussed in Huainan area at the Permian period,by collection of mud shale samples and testing the the content of the characteristics of trace elements and mineral,and collection the data of organic geochemical characteristics in the shale from previous researchers.Based on these conditions,the characteristics of the trace elements and geochemical was described,and discussed the feasibility to using trace element geochemical characteristics to predict weather the hydrocarbon source rocks is beneficial to hydrocarbon generation or not,at the same time.The results show that:Li,Sc,V,Ga,Th,Zr,Hf,Cr,Ni,U etc.are enrichment in some degree,and Be,Co,Mo,Tl,Nb,Ta etc.are deficit,other elements are not detailed when ther are compared with different background values.The Be,Cr,Zn,Rb,Sr,Mo,Tl,Nb,Ta ect.are deficit;Sb?Bi?Cu?Re ect.are enrichment and others are not detailed after correction.? REE content in shale samples is far more than it's average value in continental crust,NACS and PAAS.In shales light REE is high fractionation and heavy REE is not obvious fractionation.Ce slight negative anomaly,Eu negative anomaly is more obvious.Content characteristics of Ba,Cd,Cu,Zn,Sr,U,Mo,V,Ni,Sr,Cu and geochemical parameters of Zr/Rb,Ceanom,MoEF/UEF,Sr/Cu,Rb/Sr,(La/Yb)n are show that:depth of wate is decreased,salinity got lower,marine transformed into terrestrial facies gradually.Hydrodynamic got stronger and deposition rate became lower,climate conditions Evolution from semi-humid to semi-arid,acidic of water became weakened,reducibility recede and oxidability enhance.Productivity of basin ancient is stable,and belongs to the low nutrient waterThe results ofcultellation in Co/Th-La/Sc,La/Th-Hf,La/Yb-?REE diagram show that:type of Mud shale source rock give priority to with felsic rocks at the Permian period,at the end of this period there was sneaked into basic roc.We can found that REE patterns of shale samples is similar with it,s of continental crustal rocks.The results ofcultellation in La-Sc-Th,Th-Sc-(Zr/10),La/Yb-Yb also show that:Tectonic background of source contains the Continental arcs,Active continental margin,Passive continental margin.The hale has total organic Carbon(TOC)generally 0.11%-8.8 7%,and the average value of 8.4%in shale of Shanxi group,generally 0.11%-2.74%the average value of 1.07%in shale of Xiashihezi group and generally 0.13%-1.16%the average value of 0.57%in shale of Shangshihezi group.From early Permian to later Permian,the percentage of exinite and inert groups were rising,but the sapropel group and vitrinite were reduced.Organic geochemical characteristics of the shale is consistent with the evolution of the sedimentary environment.Its obviously show that:there will has a certain practical significance by using trace element geochemical characteristics to predict the level of hydrocarbon source rocks.