Composition and structural state of the potassic phase in perthites as related to petrogenesis of a granitic pluton
Composition and structural state of the potassic phase in perthites as related to petrogenesis of a granitic pluton
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与花岗岩岩体岩石成因相关的钾长岩中钾相的组成和结构状态
DOI：
10.1016/0024-4937(70)90072-1
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发表时间：
1970
期刊：
影响因子：
3.5
通讯作者：
P. C. Ragland
中科院分区：
文献类型：
--
作者：
P. C. Ragland
花岗岩体中条纹长石钾相的成分和结构状态的变化受岩体中水的分布控制。美国得克萨斯州中部前寒武纪Enchanted Rock岩基中的60种微线纹长石，通过X射线和光学手段进行了研究。结构状态的三个措施：结晶度，光学角，和赖特的“三峰法”的基础上定义的参数。中-中央区的条纹长石斑晶包含共存的“正长石”和中间微斜长石，而来自岩基其他岩性区和相关脉岩的钾长石中以近最大微斜长石为主。有序化程度与分异指数、钾化相的Or %呈正相关。水逸度的基础上黑云母组合物的估计结果是一致的建议模型的催化水和它的影响的反转和unmixing的成分碱菱镁矿。
Variations in composition and structural state of the potassic phase in perthites from a granitic pluton are controlled by the distribution of water within the body. Sixty microline perthites from the Precambrian Enchanted Rock batholith, central Texas, U.S.A., were investigated by x-ray and optical means. Three measures of structural state were used: obliquity, optic angle, and a parameter defined on the basis of Wright's ‘three-peak method’. Perthite phenocrysts from the intermediate-central zone contain co-existing ‘orthoclase’ and intermediate microcline, whereas near-maximum microcline predominates in K-feldspars from the other lithologic zones of the batholith and associated dike rocks. The degree of ordering correlates positively with the differentiation index, as well as %Or of the potassic phase. The results of estimates on water fugacities based upon biotite compositions are in agreement with the proposed model of catalysis by water and its effect on the inversion and unmixing of the constituent alkali feldspars.