吉林南部新太古代末地壳深熔作用——来自变质石英闪长岩及淡色花岗岩的证据     

刘建辉 《岩石矿物学杂志》2022,41(2):303-321

深熔作用是大陆地壳分异、元素迁移富集和混合岩化作用的主要机制和关键地质过程.吉南地区出露的太古宙基底普遍经历了角闪岩相-麻粒岩相变质及深熔作用,长英质淡色体及淡色花岗岩广泛分布.吉南和龙花岗-绿岩地体出露的太古宙变质石英闪长岩及相关的长英质浅色体和含斜方辉石(角闪石)淡色伟晶花岗岩的野外地质特征、相互关系及岩相学特征指...  相似文献   

Petrological Implication of the Albite Rims in the Felsic Gneisses of the Fuping Complex   总被引：1，自引：0，他引：1  

REN Liudong  YANG Chonghui  DU Lilin 《《地质学报》英文版》2012,86(2):430-439

The albite rim is present in most felsic gneisses of the Fuping Complex. The presence of the rim indicates the coexistence of plagioclase and K-feldspar in the rock. The rim is formed immediately after the myrmekite, and both textures were derived from the alteration of K-feldspar. The difference is that that there is no quartz present in the rim, and the rim is nearly albite and the anorthite content of the rim plagioclase is substantially lower than that of the myrmekite plagioclase. Formed at 400–500°C the albite rim was derived from the K-feldspar composition adjustment in the late or post-magmatism stage. As the temperature decreased, the equilibrium between K-feldspar and plagioclase could be maintained, and reactions between the minerals occurred. The leucocratic veins in the complex show distinguished magma or migmatitic characteristics. The rim might form in the late magma or deuteric stage. The formation of the rim implies obvious granitic magma- or melt-injection activity. Typical metamorphic rocks cannot produce the rims. Anatexis after medium–high grade metamorphism might be subordinate. If present, the anatexis is water-present, but the rim texture cannot be taken as the symbol of anatexis.  相似文献   

麻山杂岩的变质-混合岩化作用和花岗质岩浆活动   总被引：7，自引：3，他引：4  

任留东  王彦斌  杨崇辉  韩娟  颉颃强  李林山 《岩石学报》2010,26(7):2005-2014

在黑龙江佳木斯地块麻山杂岩中可分别有高级和中级变质作用部分,两处均可见混合岩化作用。通过混合岩浅色脉体或花岗质脉体中的长石自形晶、斜长石周围的钠长石净边、黑云母向角闪石的转化等现象表明混合岩化作用主要表现为深部岩浆的注入,而不仅是高级变质之后的近原地深熔作用所致,高级变质与相关的深熔作用所致混合岩化在区域上的分布是有限的,集中于西麻山的高级区;而注入式混合岩化是普遍的,其产出可遍布所有麻山杂岩的出露区,在麻粒岩相和角闪岩相部位均可出现。早期麻粒岩相变质与后期混合岩化作用应是相互独立的构造或热事件;注入式混合岩化引起了中级变质作用和高级区的退变质作用,注入混合岩化作用的时代约为500Ma;中级变质作用是注入混合岩化的结果,而不是混合岩化的原因。与注入混合岩相关的花岗岩虽然表现出一些S型花岗岩的特征,但根据矿物组合、地化性质的综合分析,更可能是富钾及钾长石斑晶的钙碱性花岗岩类,属于I型花岗岩,形成于挤压向引张转化的过程中。麻山杂岩的变质与混合岩化特征表明,以西伯利亚古陆为中心的南部边缘发生了与冈瓦纳陆块内泛非事件类似的构造活动,只不过这里的规模略小,在变质之后迅速发生了构造体系的转换,而形成大量花岗质岩浆活动。  相似文献