摘要
应用岩石组合及元素地球化学组合特征,已经能够较成熟的研究区域构造—岩浆演化过程,界定区域构造演化的时空界限。双峰式火山岩组合可形成于不同的大地构造背景下,笔者对不同的大地构造背景形成的双峰式火山岩的岩石学和地球化学特征进行了总结,针对在博格达造山带发现的双峰式火山岩,讨论其对构造—岩浆演化指示作用。博格达双峰式火山岩岩石组合及元素地球化学特征表明:裂谷作用始于早石炭世,结束于晚石炭世晚期或早二叠世早期。博格达裂谷作用存在东西时空差异性,根据裂谷演化早期双峰式火山岩的空间及东西天山在石炭纪火山活动的的差异,推断博格达西段裂谷作用稍微早于东段开始,但由于区域构造演化差异,裂谷演化程度东段强于西段,而东段可能早于西段裂谷闭合。
Based on application of the rock assemblage and more maturely regional tectonic - magmatic evolution, and define tectonic evolution. Bimodal volcanic rocks may occur in many geochemistry, the study attempted to analyze the spatial and temporal series of the regional different geodynamic environments, and the features of petrology and geochemistry of that are reviewed in this paper. It is suggested that the Bogda rifting started in the Early Carboniferous, ended in the end of Late Carboniferous or Early Permian and has difference from the spatial and temporal boundaries. It is inferred that the Bogda rifting of western began slightly earlier than the eastern, evolution of eastern rifting stronger than the western by the regional tectonic evolution, and east rifting may be closed earlier than the western.
出处
《甘肃地质》
2013年第4期28-36,共9页
Gansu Geology
关键词
双峰式火山岩
博格达造山带
大陆裂谷
Bimodal volcanic rocks
Bogda Orogenic belt
Continental rift