Kuratite, Ca4(Fe2+10Ti2)O4[Si8Al4O36], the Fe2+-analogue of rhönite, a new mineral from the D'Orbigny angrite meteorite
| العنوان: | Kuratite, Ca4(Fe2+10Ti2)O4[Si8Al4O36], the Fe2+-analogue of rhönite, a new mineral from the D'Orbigny angrite meteorite |
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| المؤلفون: | Maria Eugenia Varela, Shyh-Lung Hwang, Yoshiyuki Iizuka, Pouyan Shen, Hao-Tsu Chu, Tzen-Fu Yui |
| المصدر: | Mineralogical Magazine. 80:1067-1076 |
| بيانات النشر: | Mineralogical Society, 2016. |
| سنة النشر: | 2016 |
| مصطلحات موضوعية: | Ulvöspinel, 010504 meteorology & atmospheric sciences, Mineralogy, Electron microprobe, engineering.material, Triclinic crystal system, 010502 geochemistry & geophysics, 01 natural sciences, Crystallography, Sapphirine, Meteorite, Electron diffraction, Geochemistry and Petrology, engineering, Fayalite, Hedenbergite, Geology, 0105 earth and related environmental sciences |
| الوصف: | Kuratite, ideally Ca4(Fe2+10Ti2)O4[Si8Al4O36], the Fe2+-analogue of rhönite and a new member of the sapphirine supergroup, was identified from the D'Orbigny angrite meteorite by electron microscopy and micro-Raman spectroscopy. Based on the least-squares refinement of 25 d-spacings measured from selected-area electron diffraction patterns of 11 zone axes, the symmetry of kuratite was shown to be triclinic (space group by analogy to rhönite) with a = 10.513(7), b = 10.887(7), c = 9.004(18) Å, α = 105.97(13), β = 96.00(12), γ = 124.82(04)°, V = 767 ± 2 Å3 and Z = 1 for the 40 oxygen formula. The empirical formula based on eight electron microprobe analyses is (Ca3.88Na0.02REE3+0.03Mn0.03Mg0.01Ni0.02Zn0.01Sr0.01)∑4.01 (Fe2+9.989.9Ti2.00)∑11.98(Si7.80Al3.52Fe3+0.64P0.05S0.02)∑12.03O39.98F0.01Cl0.01. The simplified formula is Ca4(Fe2+10Ti2)O4[Si8Al4O36]. Micro-Raman spectroscopy showed four main bands resembling those of lunar rhönite but with higher frequencies due to different chemical composition. Analogous to the occurrence of kuratite in terrestrial basaltic rocks, kuratite coexisting with Al, Ti-bearing hedenbergite, ulvöspinel, iron-sulfide, tsangpoite, Ca-rich fayalite and kirschsteinite in D'Orbigny angrite most probably was formed at >1000°C by rapid cooling of an interstitial melt, which is subsilicic, almost Mg-free but enriched in Al-P-Ca-Ti-Fe. |
| تدمد: | 1471-8022 0026-461X |
| DOI: | 10.1180/minmag.2016.080.043 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::7435b1eab26d774a9062fe447f9b60c7 https://doi.org/10.1180/minmag.2016.080.043 |
| Rights: | CLOSED |
| رقم الانضمام: | edsair.doi...........7435b1eab26d774a9062fe447f9b60c7 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14718022 0026461X |
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| DOI: | 10.1180/minmag.2016.080.043 |