南京六合桂子山玄武岩石柱林成因初探

A Study on the Genetic Mechanism of Columnar Joints in Basalt of Liuhe Guizi Hill,Nanjing

南京六合桂子山发育规模巨大、柱体形状规则和排列有序的玄武岩石柱林。已有多种玄武岩柱状节理的成因假说,但均尚有不完备之处。玄武岩熔浆喷出地表未固结之前的双扩散对流和固结成岩阶段的冷却收缩作用,可能是形成桂子山玄武岩石柱林的主要原因。玄武岩柱状节理的形成机理十分复杂,远未达到完全解决的境地。

Some hypotheses of the genetic mechanism of columnar joints in basalt are introduced and commented in this paper. In regard to the forming mechanism of columnar joints in basalt the hypothesis of double-diffusive convection is not in contradiction with the traditional hypothesis of cooling-contraction and they are mutually complementary, both elucidating from their respective approaches the forming processes and developmental characteristics of the initial fractures in basalt in various developmental stages, such as before and after the consolidation or rockforming of molten basaltic magma, and their causal relation. These hypotheses can be used to explain clearly the formation mechanism of columnar joints in basalt of the Guizi hill,Liuhe, Nanjing.