摘要
宗乃山－沙拉扎山火山－深成岩带是个具陆壳基底的火山弧。至少自４１１Ｍａ以来，发生北侧洋壳向南的俯冲作用，形成钙－碱性火成岩组合。岩浆总体上向碱值增加的方向演化。发生于华力西末期的区域性钾交代作用，是使岛弧转变为成熟陆壳的重要标志。
The Zongnaishan-Shalazhashan volcanic-plutonic zone is a volcanic arc with continental crustal basement in northern Alaxa,Inner Monggolia.The oceanic crust to north of the arc has subducted toward south since at least 411 Ma ago,forming an evolutionary magmatic series,predominantly consisting of calc-alkaline igneous rocks.The granitoids are all of LREE enriched type,with a δEu value≥0.7.The magmatism has displayed a regular evolution tendency:SI,Na2O/K2O,An,and Nb+Y decrease,while DI,ANKC and (La/Er) N as well as the alkalinity of magma,increase.The regional potassium metasomatism occurring near the end of the Variscan period is an important indicator for the transformation of the island arc into a mature continental crust.
出处
《地球化学》
CAS
CSCD
北大核心
1994年第C00期162-172,共11页
Geochimica
基金
国家自然科学基金
