若尔盖铀矿田碳氧同位素特征及其成因  

δ^(13)C and δ^(18)O Values for Carbonate from the Zoigê Uranium Ore Field and Their Genetic Significance

作　　者：赵聪[1] 陈友良[1] 朱西养 张成江[1] 王勤 

机构地区：[1]成都理工大学地学与核技术重点实验室,成都610059 [2]核工业280研究所,四川广汉618300

出　　处：《四川地质学报》2012年第3期272-275,共4页Acta Geologica Sichuan

基　　金：国家自然科学基金项目(41072064)

摘　　要：研究了若尔盖铀矿田中灰岩、硅灰岩及方解石脉的碳氧同位素组成,结果表明产于地层中的灰岩、硅灰岩及方解石脉的δ13C值为-1.48‰～3.18‰,平均为1.51‰,为海洋沉积碳酸盐岩的碳同位素组成特征;δ18O值为-12.81‰～-3.71‰,平均为-9.92‰,在铀矿田中δ18O值最高。与成矿作用关系最为密切的含矿方解石脉δ13C值为-2.78‰～-4.81‰,平均为-3.93‰,明显表现为地幔来源的特点;δ18O值为-13.14‰～-15.05‰,平均为-13.87‰,其值在铀矿田中介于地层中岩石(脉)与矿区方解石脉之间。矿区方解石脉的δ13C值为-3.53‰～-6.35‰,平均为-4.93‰,与含矿方解石脉的碳同位素组成相近,表明其亦是成矿作用的产物;δ18O值为-16.00‰～-24.75‰,平均为-19.36‰,在铀矿田中δ18O值最低,明显表现为深部来源特征。综合若尔盖铀矿田的碳氧同位素组成特征,暗示其成矿流体应当来源于地幔。This paper deals with δ13C and δ18O values for limestone, siliceous limestone and vein calcite from the ZoigE uranium ore field. The δ13C values vary from -1.48‰ to 3.18‰ with an average value of 1.51‰ characteristic of marine sedimentary carbonate and the δ18O values from -12.81‰ to -3.71‰ with an average value of -9.92‰. The δ13C values of the ore-bearing vein calcite range from -2.78‰ to -4.81‰ with an average of -3.93‰ characteristic of mantle-derived carbon and the δ18O values range from -13.14‰ to -15.05‰ with an average value of-13.87‰ ranging between the dyke and vein calcite in the uranium ore field. The δ13C values vary from -3.53‰ to -6.35‰ with an average of-4.93%o which are the same as the δ13C values for ore-bearing vein calcites, showing that it is also the product of mineralization. And the δ18O values vary from -16.00‰ to -24.75‰ with an average of -19.36‰ which is the lowest in the uranium ore field and is characteristic of deep sources. In a word, δ13C and δ18O values for carbonate from the Zoige uranium ore field indicate that the ore fluids should be mantle-derived.

关 键 词：铀矿田 碳氧同位素 成因 若尔盖 

分 类 号：P619.14[天文地球—矿床学]