Geochemistry And Metallogeny Of The Daliangzikou Graphite Deposit In Laiyang Country,Shandong Province

The Pingdu-Laixi metallogenic subzone is one of the most inportant graphite accumulation area in Jiaodong metallogenic belt,North China.The study area?i.e.the Daliangzikou graphite deposit?,which is located in the eastern part of this metallogenic subzone,belongs to the northern part of the Jiaolai depression and adjacent to the Jiaobei uplift geotectonically.Combining the detailed field investigation with a series of advanced testing methods,such as the major and trace elements,carbon isotope analysis,this paper recognized the primary rock of the metamorphic rocks,discussed the material sources and backgrounds of the protoliths and explored the genesis of graphite ore.The main points of understanding are as follows:?1?The graphite deposit in the study area is distributed in a north-eastward direction,orebody is located at the limb of the regional fold and controlled by stratum.The ore-bearing stratum are hosted in the Xucun section,the Douya formation,the Paleoproterozoic Jingshan Group.This section is a combination of biotite granulite,feldspar quartzite and marble.The scaly crystalline graphite is frequently observed in the biotite granulite.?2?Geochemical characteristics show that the metamorphic rocks are enriched in silicon,aluminum and potassium,which are similar to the Khondalite.The geochemical characteristics and related graphic analysis common support that the metamorphic protoliths are sedimentary rocks,which dominated by greywacke?including feldspar sandstones and hard sandstones?and volcanic rocks.The source of the sedimentary rocks are inferred to be felsic rocks.The sedimentary environment is shallow marine facies near the active continental margin.,which also shows the characteristics of continental island arc.?3?By the comparison of the ¹³C isotope of the graphite ore samples from this deposit with other kinds of graphite ores,it is considered that the carbon source of this graphite deposit in this region was organic carbon,with a small amount of inorganic carbon.?4?The Daliangzikou graphite deposit,whch formed in the Paleoproterozoic marine basin and suffered the metamorphosed by late tectonic movement,belongs to a sedimentary metamorphic graphite deposit.