Evoluation on the Cambrian-Ordovician Marine Source Rocks from the North Tarim Basin

Based on the statistical analyses of the Cambrian-Ordovician source rocks from the North Tarim Uplift and its neighboring areas,it can be concluded that the Cambrian and lower Ordovician carbonate rocks should be the main source rocks of this areas comparatively,the Cambrian sourece rocks are totally better than the Ordovician because their contents of organic matters are higher than the Ordovician on average.Therefore the Cambrian mudstones and carbonate rocks are the most important source rocks.On the contrary,most of the mid upper Ordovician mudstones are bad or non source rocks in the study area except some outcrops.Overall,the abundance of organic matters of the Cambrian Ordvician mudstones is higher in the east and west ends than in the other areas,where the mudstones can be regarded as intermediate to excellent source rocks.Nevertheless,the Ordovivian mudstones in the Caohu,Lunnan,Yingmaili and Manjiaer regions are generally bad or non source rocks.Carbonate source rocks are also good in the east regions including Kuerle and Kuluketage,and those in Halahatang depression are the secondary.