摘要
近几年来,我国一些地质工作者把1220岩体误认为地貌上具正地形的破火山口,并把这种具正地形的“破火山口”做为寻找铀矿的一种标志。笔者从近年来所获的资料出发,论证了1220岩体是一个具隐爆相特征的次碎花岗斑岩穹窿体。并对“1220破火山口”及其控铀问题提出异议。
According to geological results gained in recent years,the author holds that"1220 Caldera"with positive landform features does not exist in nature.For example,the development of three complete facies zones within"the caldera",regular variations of the mineral composition and crushed phenocrysts,northward compression and westward tension shown by secondary fracture structures and concentration of a series of mineral deposits in the northern and western parts of"the caldera",--all these cannot be explained by the hypothesis of"1220 Caldera",It may be seen from above that the hypothesis of"1220 Caldera"is a false phenomenon,which results from not strict distinction of two geological masses(subvolcanic rocks and effusive lavas)of similar appearance and different origins in the field work.So what controls the 1220 uranium orefield is not a caldera but a subvolcanic crushed granite porphyry dome characterized by cryptoexplosive phase.
作者
卞金忠
Bian Jinzhong(Geological Party No.262,East China Geological Exploration Bureau)
出处
《地质论评》
1986年第4期390-395,共6页
Geological Review
