粤西福湖岭加里东混合岩-花岗岩形成温度研究

发布时间：2018-03-24 11:35

  本文选题：钦-杭结合带　切入点：福湖岭剖面　出处：《岩石学报》2017年03期

【摘要】：钦-杭结合带南段广泛发育加里东期的混合岩和混合花岗岩。研究这些混合岩和混合花岗岩形成的P-T条件,不但有助于了解加里东造山阶段本区地壳内部的温度特征,对于花岗岩浆形成以及大陆流变等理论问题的研究也有重要意义。本文讨论的福湖岭剖面位于钦-杭结合带南端,为一海边岩壁,其上出露分带清晰的加里东期混合岩-混合花岗岩,自上而下依次为斑点状混合岩、条纹状混合岩、窄条带状混合岩、宽条带状混合岩及混合花岗岩。作者在野外对剖面上不同类型的岩石进行了影像采样,在计算机上对采集影像样品进行处理,在统一阀值下转换成代表浅色体(熔体)和暗色体(未熔岩石或熔渣)的黑白影像,并统计浅色体的含量百分比(熔体比)。将由此得到的各类岩石熔融比数据投到用Winkler and von Platen(1961)的硬砂岩熔融实验数据构成的温度-熔体比曲线图上,获知该剖面混合岩的形成温度在630~705℃之间,原岩的熔断温度("脏"花岗岩浆生成温度)为705℃,岩石熔融时(439~445Ma)剖面的埋深大体处于当时地表以下7km左右。本文结合福湖岭剖面地质研究和岩石熔融实验数据建立的"熔融温度计",为混合岩-混合花岗岩形成温度的测定提供了一种新方法,不仅适用于福湖岭,也可用于其它地区。
[Abstract]:Caledonian migmatite and migmatite are widely developed in the southern part of the Qinghang combined belt. Studying the P-T conditions of these migmatite and migmatite is not only helpful to understand the temperature characteristics of the crust in the Caledonian orogenic stage. It is also important to study the formation of granitic magma and continental rheology. The Fuhuling section discussed in this paper is located at the southern end of Qinghang joint zone and is a seaside rock wall. The clear Caledonian migmatite-migmatite in the upper outcrop zone is followed by speckled migmatite, striped migmatite, narrow stripe migmatite, and narrow stripe migmatite from top to bottom. Wide banded migmatite and mixed granite. In the field, the authors sampled different types of rocks in the profile and processed the image samples on the computer. Converted to black and white images representing light-colored bodies (melts) and dark ones (without lava or slag) at the unified threshold, And the percentage of the content of the light-colored body (melt ratio) is calculated. The obtained melting ratio data of various kinds of rocks are put into the temperature-melt ratio curve of the hard sandstone melt experiment data of Winkler and von platform. The formation temperature of migmatite in this section is between 630 鈩，

本文编号：1658126