Occurrence of Uranium in Hydrocarbon of Chang-7 Member of Yanchang Formation of Ordos Basin

The 7th member of Yanchang Formation 0f Late Triassic in Ordos Basin is a U-rich hy-drocarbon source rocks rich in collophane,frambodial pyrite,and organic matter.In this paper the uranium occurrence in the rock of the Chang-7Member is studied using Ray,Scanning electron microscope,electron microscopy,energy spectrum analysis,and α radiography photo.The result shows that the uranium exists not only in an isomorphism uranium form but also in pyrite and oganic matters in organic matter in an adsorption form.In addition,for the first time,find that the uranium exists incollophane mineral in an independent form of uranium minearal,with the particle size between 2-14μm.It can be roughly divided into two types of uranium minerals:uranium stone,titanium.