Stable strontium isotope fractionation during crystal-melt separation in granitic magma evolution

IF 1.3 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Acta Geochimica Pub Date : 2025-01-08 DOI:10.1007/s11631-024-00752-9

Xuqi Chen, Gengxin Deng, Dingsheng Jiang, Xiaoyun Nan, Fang Huang

{"title":"Stable strontium isotope fractionation during crystal-melt separation in granitic magma evolution","authors":"Xuqi Chen, Gengxin Deng, Dingsheng Jiang, Xiaoyun Nan, Fang Huang","doi":"10.1007/s11631-024-00752-9","DOIUrl":null,"url":null,"abstract":"<div>Stable Sr isotopic composition (δ88/86Sr) can be used to study magmatic processes, but their fractionation mechanism during magmatic evolution remains unclear. To understand the fractionation behaviors of the stable Sr isotopes during magmatism, we report the δ88/86Sr values of the Huili granitic pluton, which was subjected to intensive crystal-melt separation. The Huili pluton consists of K-feldspar granite and more evolved albite granite, and the albite granite exhibits significantly higher δ88/86Sr values (+ 0.36‰ to + 0.52‰) than that of K-feldspar granite (+ 0.11‰ to + 0.25‰). K-feldspar, which contributes most of the Sr budget of the K-feldspar granite, has slightly lower δ88/86Sr values (− 0.01‰ to + 0.17‰) than the whole rock. The δ88/86Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals, because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt. Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction, reflecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt. This study indicates that melt extraction plays a key role in granitic magma evolution.</div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 4","pages":"731 - 739"},"PeriodicalIF":1.3000,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Geochimica","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s11631-024-00752-9","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}

引用次数: 0

Abstract

Stable Sr isotopic composition (δ^88/86Sr) can be used to study magmatic processes, but their fractionation mechanism during magmatic evolution remains unclear. To understand the fractionation behaviors of the stable Sr isotopes during magmatism, we report the δ^88/86Sr values of the Huili granitic pluton, which was subjected to intensive crystal-melt separation. The Huili pluton consists of K-feldspar granite and more evolved albite granite, and the albite granite exhibits significantly higher δ^88/86Sr values (+ 0.36‰ to + 0.52‰) than that of K-feldspar granite (+ 0.11‰ to + 0.25‰). K-feldspar, which contributes most of the Sr budget of the K-feldspar granite, has slightly lower δ^88/86Sr values (− 0.01‰ to + 0.17‰) than the whole rock. The δ^88/86Sr variation of the Huili granites can be explained by separation of melt from K-feldspar-dominated crystals, because crystallization of K-feldspar can result in heavy Sr isotopic composition of the extracted interstitial melt. Stable Sr and Ba isotopic ratios in the Huili granites are highly coupled toward the heavy direction, reflecting their similar element partitioning and isotope fractionation behaviors between the crystalline K-feldspar and melt. This study indicates that melt extraction plays a key role in granitic magma evolution.

查看原文本刊更多论文

花岗岩岩浆演化中结晶-熔体分离过程中稳定锶同位素分馏

稳定Sr同位素组成（δ88/86Sr）可用于研究岩浆过程，但其在岩浆演化过程中的分馏机制尚不清楚。为了了解岩浆活动中稳定Sr同位素的分馏行为，我们报道了辉里花岗岩岩体的δ88/86Sr值，该岩体经历了强烈的结晶-熔体分离。辉里岩体由钾长石花岗岩和演化较早的钠长石花岗岩组成，钠长石花岗岩的δ88/86Sr值（+ 0.36‰~ + 0.52‰）明显高于钾长石花岗岩（+ 0.11‰~ + 0.25‰）。钾长石的δ88/86Sr值（−0.01‰~ + 0.17‰）略低于整个岩体。汇里花岗岩的δ88/86Sr变化可以用熔融体与钾长石为主的晶体分离来解释，因为钾长石的结晶可以导致萃取的间隙熔体的Sr同位素组成重。辉里花岗岩中Sr和Ba同位素稳定比值向重质方向高度耦合，反映了晶体钾长石与熔体之间相似的元素分配和同位素分选行为。研究表明，熔融萃取在花岗质岩浆演化过程中起着关键作用。

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分钟内获得全文求助全文

来源期刊

Acta Geochimica GEOCHEMISTRY & GEOPHYSICS-

CiteScore

2.80

自引率

6.20%

发文量

1134

期刊介绍： Acta Geochimica serves as the international forum for essential research on geochemistry, the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth‘s crust, its oceans and the entire Solar System, as well as a number of processes including mantle convection, the formation of planets and the origins of granite and basalt. The journal focuses on, but is not limited to the following aspects: • Cosmochemistry • Mantle Geochemistry • Ore-deposit Geochemistry • Organic Geochemistry • Environmental Geochemistry • Computational Geochemistry • Isotope Geochemistry • NanoGeochemistry All research articles published in this journal have undergone rigorous peer review. In addition to original research articles, Acta Geochimica publishes reviews and short communications, aiming to rapidly disseminate the research results of timely interest, and comprehensive reviews of emerging topics in all the areas of geochemistry.