In:
Journal of Raman Spectroscopy, Wiley, Vol. 53, No. 12 ( 2022-12), p. 2110-2122
Abstract:
Inclusions of former alkaline carbonate melts occur in igneous minerals, mantle xenoliths, and diamonds from kimberlites and lamproites. However, the identification of most daughter phases remains undetermined owing to the lack of their Raman spectra. Yet, the phase compositions of the alkali carbonate melt at different pressure are interesting to know because Na‐Ca, Na‐Mg, K‐Ca, and K‐Mg double carbonates have a number of pressure‐induced phase transitions. Here, we studied the quench products of K‐Ca, K‐Mg, and Na‐Ca carbonate melts obtained at 3 and 6 GPa. Scanning electron microscopy coupled with energy‐dispersive spectroscopy with silicon drift detector (EDS‐SDD) and Raman spectroscopy were employed for phase characterization. The following carbonates were detected among the quench products: γ‐Na 2 CO 3 , Na 4 Ca(CO 3 ) 3 ( Ia 3 d ), Na 2 Ca 3 (CO 3 ) 3 ( P 1 n 1), K 2 Ca(CO 3 ) 2 (
) bütschliite, disordered K 2 Ca 3 (CO 3 ) 4 ( Pnam ), K 2 Mg(CO 3 ) 2 (
), aragonite, magnesite at 6 GPa; and CaCO 3 ‐bearing K 2 CO 3 , K 2 Ca(CO 3 ) 2 (
) bütschliite, K 2 Ca 2 (CO 3 ) 3 ( R 3), and ordered K 2 Ca 3 (CO 3 ) 4 ( P 2 1 2 1 2 1 ) at 3 GPa. The results indicate that the quench products of carbonate melt consist of carbonates thermodynamically stable at the pressure of quenching. Thus, the daughter phases in carbonatitic inclusions could be identified by obtained Raman spectra and reflect the pressure conditions of their entrapment.
Type of Medium:
Online Resource
ISSN:
0377-0486
,
1097-4555
Language:
English
Publisher:
Wiley
Publication Date:
2022
detail.hit.zdb_id:
1481008-6
SSG:
11
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