摘要
角闪石作为南太行山地区中基性侵入岩中主要组成矿物,其详细的成因矿物学研究对了解该套岩石的形成机理具有重要意义。电子探针分析表明角闪石的成分变化很大如SiⅣ、AlⅣ和A位置上的Na和K离子,主要为韭闪石、韭闪石质普通角闪石、普通角闪石和阳起石质普通角闪石。且富镁和钙,为钙镁质角闪石。同时,不同岩石类型中的角闪石的组成无显著差异。大颗粒的核心部位形成于深部岩浆房中(18 ~25km),其组成的连续变化主要反映结晶深度的不同。角闪石的成因矿物学研究表明该套岩石不可能来源于华北古老的下地壳,而可能起源于新增生的下地壳和/或壳幔过渡带。
As one of major mineral phases in the intermediate-mafic intrusions in Southern Taihang Mountains, amphibole can be used to constrain its petrogenesis. Electron microprobe data show that the amphiboles have a large variation range in composition such as Si^(IV), Al^(IV) and A-site occupied Na and K cations. They are all Ca- and Mg-rich and mainly pargasite, pargasitic hornblende, hornblende, actinolitic hornblende. These amphiboles, especially larger grains, are characterized by ubiquitous presence of textural and chemical zonation. Furthermore, no obvious compositional differences exist between amphiboles from different rock types. The core of the large grain crystallized from magma chamber at depth (18~25 km), and its continuous compositional changes mainly reflect the difference in depth at which they were crystallized. The petrogenesis on the hornblende demonstrates this suite of rocks would not have originated from the old lower crust of the North China craton, but could have been derived from newly accreted lower crust and/or the crust-mantle transitional zone.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2005年第2期269-277,共9页
Geotectonica et Metallogenia
基金
国家杰出青年科学基金(编号 40225009)资助项目.
关键词
南太行山地区
中生代
中基性侵入岩
角闪石
岩石成因
Southern Taihang Mountains
Mesozoic
intermediate-mafic intrusions
amphibole
petrogenesis
