摘要
丹凤—西峡一带的早古生代花岗岩类均具有岛弧花岗岩的地球化学特征,它们是早古生代时期秦岭古洋板块以商丹断裂带为主缝合带向北东方向俯冲消减作用的产物,这些花岗岩类岩株和岩基在同种岩石类型和SiO_2含量相近的前提下,岩石中的K_2O、K_2O+Na_2O含量、K_2O/Na_2O比值以及∑REE、La、Rb、Th、Zr、δ^(18)O含量与初始^(87)Sr/^(86)Sr比值均具有成分极性,即从俯冲带向大陆一侧具有成分穿弧空间变化,这是由于从俯冲带向大陆一侧,岩体岩浆中壳源物质增加,而幔源物质降低所造成的结果。
The Early Paleozoic granitoids in the Danfeng-Xixia area have geochemical characteristics of arc granitoids, and were products of the northeastern subduction of the paleo-Qin-ling ocean along the Shangdan main suture. At similar SiO2 levels, granitoids of the same type, in form of either stock or batholith, all show compositional trans-arc polarities, i. e. increase towards continent in K,O. K2O + Na2O, K2O/Na2O, ΣREE, La, Rb, Th, Zr, δ18O and 87Sr/86Sr. The polarity can be attributed to the corresponding increase of crustal components in the magma source towards the same direction.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
1993年第1期67-72,共6页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金
地质行业科学发展基金(项目号48970171)
关键词
花岗岩
成分
壳源物质
幔源物质
North Qinling, arc granitoids, compositional polarity, crust-derived material, mantle-derived material.
