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Crystal chemistry and isomorphism of high-calcium eudialyte-group minerals from the Tamazeght peralkaline complexстатья Исследовательская статья
Дата последнего поиска статьи во внешних источниках: 1 апреля 2026 г.
- Авторы: Chukanov N.V., Zolotarev A.A., Gridchina V.M.Moëlo Y, Ermolaeva V.N., Vigasina M.F., Stephant N., Aksenov S.M., Rastsvetaeva R.K.
- Журнал: Mineralogical Magazine
- Год издания: 2026
- Издательство: Mineralogical Society
- Местоположение издательства: United Kingdom
- Первая страница: 1
- Последняя страница: 16
- DOI: 10.1180/mgm.2025.10125
- Аннотация: Crystal-chemical features of high-calcium and hypercalcium eudialyte-group minerals (EGMs) from a carbonatite-related rock of the Tamazeght peralkaline complex, High Atlas Mountains, Morocco were studied using electron probe microanalysis, single-crystal X-ray structure analysis, infrared and Raman spectroscopy. The major components of the host rock are calcite, fluorite and EGMs; aegirine–augite is present in subordinate amounts. The specific features of the studied EGMs are chemical heterogeneity, a complex zoning, reaction zones around calcite and apatite inclusions, Na- and Cl-deficiency, high contents of Ca, Mn, REE, Nb, carbonate and H-bearing groups, positive correlation between Nb and Mn and negative correlations between the pairs Fe–Mn and Zr–Mn. These features confirm previous assumptions about the role of infiltration of carbonatite fluid rich in Ca, Mn, REE, Nb, CO2 and H2O and a depletion of Cl in the remaining fluid after the crystallization of sodalite at the expense of nepheline in the formation of carbonatite-related rocks of the Tamazeght complex.The crystal structure of a single-crystal fragment extracted from the Nb-rich zone refined to R1 = 0.0335 has shown a high degree of ordering of Na, REE and H3O+ and the dominance of Fe3+ at the M2 site with five-fold coordination. The composition of EGMs from the reaction zones around calcite and apatite inclusions corresponds to Mn-dominant (with Mn > Fe at the M2 site) analogue of feklichevitewith the simplified formula Ca3(Na,K)9(H3O)3Ca6Zr3(Mn2+,Fe3+,Zr)3NbSi(Si24O72).(OH,H2O)5(F,Cl)2/3(CO3)1/3.
- Добавил в систему: Ермолаева Вера Никитична
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