A grain boundary model of metamorphic reaction

IF 3.5 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Contributions to Mineralogy and Petrology Pub Date : 2024-03-15 DOI:10.1007/s00410-024-02100-9

Frank S. Spear

{"title":"A grain boundary model of metamorphic reaction","authors":"Frank S. Spear","doi":"10.1007/s00410-024-02100-9","DOIUrl":null,"url":null,"abstract":"<div><p>A model is presented whereby metamorphic parageneses are governed by local, nano-scale reactions among adjacent phases along grain boundaries that are driven by local disequilibrium between the solid phases and the grain boundary composition. These reactions modify the grain boundary composition setting up compositional gradients that drive diffusion and change the grain boundary composition elsewhere in the rock, which drive local reactions in these locations. The process may be triggered by the nucleation of a new phase that is out of equilibrium with the existing assemblage and an example is presented based on the transformation of kyanite (Ky) to sillimanite (Sil). Model results reveal that a simple polymorphic transformation (Ky→Sil) can result in local reactions among all phases in the rock and some phases may grow in one locale and be consumed in another. An implication of these results is that interpretation of metamorphic parageneses based on growth or resorption and compositional changes of phases requires careful evaluation of nano-scale processes.</p></div>","PeriodicalId":526,"journal":{"name":"Contributions to Mineralogy and Petrology","volume":"179 4","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00410-024-02100-9.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Contributions to Mineralogy and Petrology","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s00410-024-02100-9","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}

引用次数: 0

Abstract

A model is presented whereby metamorphic parageneses are governed by local, nano-scale reactions among adjacent phases along grain boundaries that are driven by local disequilibrium between the solid phases and the grain boundary composition. These reactions modify the grain boundary composition setting up compositional gradients that drive diffusion and change the grain boundary composition elsewhere in the rock, which drive local reactions in these locations. The process may be triggered by the nucleation of a new phase that is out of equilibrium with the existing assemblage and an example is presented based on the transformation of kyanite (Ky) to sillimanite (Sil). Model results reveal that a simple polymorphic transformation (Ky→Sil) can result in local reactions among all phases in the rock and some phases may grow in one locale and be consumed in another. An implication of these results is that interpretation of metamorphic parageneses based on growth or resorption and compositional changes of phases requires careful evaluation of nano-scale processes.

Abstract Image

查看原文

微信好友朋友圈 QQ好友复制链接

本刊更多论文

变质反应的晶界模型

本文提出了一个模型，根据该模型，变质副成因受沿晶界相邻相之间的局部纳米尺度反应的支配，而这些反应是由固相和晶界成分之间的局部不平衡所驱动的。这些反应改变了晶界成分，形成了成分梯度，推动了扩散，改变了岩石中其他地方的晶界成分，从而推动了这些地方的局部反应。这一过程可能是由与现有组合失去平衡的新相的成核引发的，并以闪长岩（Ky）转变为矽线石（Sil）为例进行了说明。模型结果表明，简单的多晶体转变（Ky→Sil）会导致岩石中所有相之间发生局部反应，一些相可能在一个地方生长，而在另一个地方被消耗掉。这些结果的含义之一是，根据相的生长或吸收以及成分变化来解释变质副成因，需要对纳米尺度的过程进行仔细评估。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文去求助

来源期刊

Contributions to Mineralogy and Petrology 地学-地球化学与地球物理

CiteScore

6.50

自引率

5.70%

发文量

审稿时长

1.7 months

期刊介绍： Contributions to Mineralogy and Petrology is an international journal that accepts high quality research papers in the fields of igneous and metamorphic petrology, geochemistry and mineralogy. Topics of interest include: major element, trace element and isotope geochemistry, geochronology, experimental petrology, igneous and metamorphic petrology, mineralogy, major and trace element mineral chemistry and thermodynamic modeling of petrologic and geochemical processes.