Academic Journal
Newly detected shock-induced high-pressure phases formed in amphibolite clasts of the suevite breccia (Ries impact crater, Germany): Liebermannite, kokchetavite, and other ultrahigh-pressure phases
| العنوان: | Newly detected shock-induced high-pressure phases formed in amphibolite clasts of the suevite breccia (Ries impact crater, Germany): Liebermannite, kokchetavite, and other ultrahigh-pressure phases |
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| المؤلفون: | Stähle, Volker, Chanmuang N., Chutimun, Schwarz, Winfried H., Trieloff, Mario, Varychev, Alexander |
| المساهمون: | Ruprecht-Karls-Universität Heidelberg |
| المصدر: | Contributions to Mineralogy and Petrology ; volume 177, issue 8 ; ISSN 0010-7999 1432-0967 |
| بيانات النشر: | Springer Science and Business Media LLC |
| سنة النشر: | 2022 |
| الوصف: | Amphibolite clasts in the suevite of the Ries impact crater contain shock-induced melt veins (SMVs) with high-pressure phases such as majoritic garnet, jadeitic clinopyroxene and others. In addition, heat conduction from hot SMVs into adjacent rock portions locally produced further high P – T melt pools. These melts were preferentially generated in rock domains, where the SMVs cross older (‘pre-Ries’) veinlets with analcime or prehnite and larger grains of sericitized plagioclase. Melting of such chemically different local bulk systems (Na-, Ca-, Ca-Na- and K-Na-rich) was facilitated by low solidus temperatures of the original secondary OH-bearing phases. From the resulting shock-induced melts, liebermannite, kokchetavite, jadeite, nonstoichiometric and albitic jadeite, grossular, vuagnatite, lawsonite + coesite, and clinozoisite crystallized during pressure release. Vuagnatite is now proven to be a genuine high-pressure phase. Its ubiquitous distance of 20–35 μm from the hot shock veins suggests a temperature sensitivity typical for an OH-bearing phase. In local Na-rich melts albitic jadeite appears instead of the assemblage jadeite + SiO 2 . Liebermannite, a dense polymorph of K-feldspar was identified by Raman spectroscopy. After stishovite, liebermannite constitutes the second known high-pressure phase in the Ries that contains silicon exclusively in six-fold coordination. The KAlSi 3 O 8 -polymorph kokchetavite was formed in alkali-rich melt glasses. Pressure and temperature values in the range of about 8–11 GPa and ~ 800–1100 °C were estimated from the chemical compositions of locally occurring majoritic garnets (Si = 3.21–3.32 and 3.06–3.10 apfu), respectively, and the presence of fine-grained aggregates of lawsonite and coesite. Generally, the neighboring areas of the veins are characterized by a sequence of variable high-pressure phases documenting strongly falling P–T conditions with increasing distance from the vein. These novel features enlighten the dynamic event during passage of a shock ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1007/s00410-022-01936-3 |
| DOI: | 10.1007/s00410-022-01936-3.pdf |
| DOI: | 10.1007/s00410-022-01936-3/fulltext.html |
| الاتاحة: | http://dx.doi.org/10.1007/s00410-022-01936-3 https://link.springer.com/content/pdf/10.1007/s00410-022-01936-3.pdf https://link.springer.com/article/10.1007/s00410-022-01936-3/fulltext.html |
| Rights: | https://creativecommons.org/licenses/by/4.0 ; https://creativecommons.org/licenses/by/4.0 |
| رقم الانضمام: | edsbas.12D5ADA4 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1007/s00410-022-01936-3 |
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