Crustal anatectic origin of the pegmatitic carbonate rocks in the Proterozoic Highland Complex, Sri Lanka

IF 3.5 2区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS
Ben-Xun Su, Shi-Ying Wang, P. L. Dharmapriya, Jing Wang, Sanjeewa P. K. Malaviarachchi, Kui-Feng Yang, Hong-Rui Fan
{"title":"Crustal anatectic origin of the pegmatitic carbonate rocks in the Proterozoic Highland Complex, Sri Lanka","authors":"Ben-Xun Su,&nbsp;Shi-Ying Wang,&nbsp;P. L. Dharmapriya,&nbsp;Jing Wang,&nbsp;Sanjeewa P. K. Malaviarachchi,&nbsp;Kui-Feng Yang,&nbsp;Hong-Rui Fan","doi":"10.1007/s00410-024-02178-1","DOIUrl":null,"url":null,"abstract":"<div><p>Pegmatitic dyke-like carbonate rocks mainly composed of very coarse-grained calcite, are a rare type of carbonate rocks found in some of orogenic belts in the world. These specific carbonate rocks generally occur intimately with high-temperature granulites and marbles. In the Proterozoic Highland Complex of Sri Lanka which is a segment of the Mozambique suture, they are associated with marbles and granitic pegmatites, and intercalated with high-grade calc-silicate gneisses and highly folded ortho- and para-gneisses. These pegmatitic carbonate rocks do not show any signs of metamorphic or deformed overprint, but instead well preserve igneous textures and contain various silicate crustal xenoliths. The calcite crystals occur as euhedral to subhedral grains and are large in size from 1 to 15 cm. The diverse colors of calcite from white to yellow and blue derive from mineral inclusions and their own compositions. Non-carbonate minerals, commonly present in typical carbonatites such as phlogopite, apatite, clinopyroxene, olivine, plagioclase, iron oxides and spinel, are all found in the rocks. Meanwhile, a skarn-type assemblage of wollastonite, garnet, clinopyroxene and sulfide occurs in contact between the carbonate rocks and gneiss xenoliths, which probably resulted from antiskarn reactions. Chemical compositions of major constituent minerals (calcite, dolomite and apatite) of the carbonate rocks are intermediate between typical marbles and mantle-derived carbonatites and akin to crustal-origin carbonatites worldwide. We thus classify the studied rocks as ‘anatectic carbonatite pegmatite’, and suggest that they originated from the melting of a mixture of marbles and surrounding silicate rocks at crustal levels during high-temperature metamorphism.</p></div>","PeriodicalId":526,"journal":{"name":"Contributions to Mineralogy and Petrology","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Contributions to Mineralogy and Petrology","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s00410-024-02178-1","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

Pegmatitic dyke-like carbonate rocks mainly composed of very coarse-grained calcite, are a rare type of carbonate rocks found in some of orogenic belts in the world. These specific carbonate rocks generally occur intimately with high-temperature granulites and marbles. In the Proterozoic Highland Complex of Sri Lanka which is a segment of the Mozambique suture, they are associated with marbles and granitic pegmatites, and intercalated with high-grade calc-silicate gneisses and highly folded ortho- and para-gneisses. These pegmatitic carbonate rocks do not show any signs of metamorphic or deformed overprint, but instead well preserve igneous textures and contain various silicate crustal xenoliths. The calcite crystals occur as euhedral to subhedral grains and are large in size from 1 to 15 cm. The diverse colors of calcite from white to yellow and blue derive from mineral inclusions and their own compositions. Non-carbonate minerals, commonly present in typical carbonatites such as phlogopite, apatite, clinopyroxene, olivine, plagioclase, iron oxides and spinel, are all found in the rocks. Meanwhile, a skarn-type assemblage of wollastonite, garnet, clinopyroxene and sulfide occurs in contact between the carbonate rocks and gneiss xenoliths, which probably resulted from antiskarn reactions. Chemical compositions of major constituent minerals (calcite, dolomite and apatite) of the carbonate rocks are intermediate between typical marbles and mantle-derived carbonatites and akin to crustal-origin carbonatites worldwide. We thus classify the studied rocks as ‘anatectic carbonatite pegmatite’, and suggest that they originated from the melting of a mixture of marbles and surrounding silicate rocks at crustal levels during high-temperature metamorphism.

Abstract Image

斯里兰卡新生代高地复合体中伟晶岩碳酸盐岩的地壳北极起源
主要由粗粒方解石组成的伟晶岩堤状碳酸盐岩是一种罕见的碳酸盐岩,分布于世界上一些造山带。这些特殊的碳酸盐岩一般与高温花岗岩和大理岩紧密伴生。在斯里兰卡的新生代高地群(莫桑比克缝合线的一段)中,它们与大理岩和花岗伟晶岩伴生,并与高品位钙硅酸盐片麻岩以及高度褶皱的正长片麻岩和副片麻岩互生。这些伟晶岩碳酸盐岩没有任何变质或变形覆盖的迹象,而是很好地保留了火成岩的纹理,并含有各种硅酸盐地壳异石。方解石晶体为八面体至近八面体晶粒,尺寸较大,从 1 厘米到 15 厘米不等。方解石的颜色多种多样,有白色、黄色和蓝色,这些都是由矿物包裹体及其自身成分造成的。岩石中还发现了典型碳酸盐岩中常见的非碳酸盐矿物,如辉石、磷灰石、倩辉石、橄榄石、斜长石、铁氧化物和尖晶石。同时,在碳酸盐岩与片麻岩斜长岩的接触处,出现了由硅灰石、石榴石、鳞辉石和硫化物组成的矽卡岩型集合体,这可能是由反矽卡岩反应造成的。碳酸盐岩主要成分矿物(方解石、白云石和磷灰石)的化学成分介于典型的大理岩和地幔源碳酸盐岩之间,与世界各地的地壳源碳酸盐岩相似。因此,我们将所研究的岩石归类为 "无主碳酸盐伟晶岩",并认为它们起源于高温变质过程中大理岩和周围硅酸盐岩在地壳层面的混合熔融。
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
Contributions to Mineralogy and Petrology
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
94
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.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信