摘要
本文根据近年来的地质调查和实验研究的最新进展,分析和评述了六种主要的细碧岩成因假说。其中岩浆结晶观点如原生岩浆结晶说、派生岩浆结晶说、混染岩浆结晶说;后成改造观点有内源热液交代说、外源热液交代说、变质热液交代说。笔者认为,用后威改造作用,其中主要是循环海水的低温蚀变作用和低级变质作用来解释细碧岩的成因可能比较合理。因为,这一假说既能比较满意地解释细碧岩的化学成分、矿物组成、岩石组合、结构构造和产出地质环境等方面的特征,尤其是细碧岩的低温矿物和高温组构与现代洋底蚀变玄武岩之间的相似性;又有实验资料,尤其是海水—玄武岩交换反应和钠长石化实验中,元素迁移和矿物变化规律的最新研究成果作支柱。
Spilite-keratophyre series, characterised by high-temperature fabricsand low-temperature mineral assemblages, are a unique volcanic association that has long been studied. But up to now, scientists do not agree on their geneses. In the past decades, quite a few genetic hypotheses of spilite have been proposed, and they may be summed up into two categories: magma crystallization theory and epigenetic reformation theory.Each containing three major hypotheses. Recent achievements in the study of modern oceanic altered basalts and in the experiments of seawater basalt interaction indicate that the hydrothermal alteration and metamorphism play a determinant part in the formation of spilite. Therefore, the epigenetic reformation theory including low-grade metamorphism and low-temperature alteration by circulating seawater is more reasonable, because it can more explain characteristics of spilite and experimental results satisfactorily, and harmoniously merge the petrogenesis of spilite and metallogenesis of massive sulfide deposits into a single model of convection circulation of hot brine on seafloor.
出处
《地质科技情报》
CAS
CSCD
北大核心
1990年第1期19-24,共6页
Geological Science and Technology Information
