Инд. авторы:	Zedgenizov D.A., Kagi H., Ohtani E., Tsujimori T., Komatsu K.
Заглавие:	Retrograde phases of former bridgmanite inclusions in superdeep diamonds
Библ. ссылка:	Zedgenizov D.A., Kagi H., Ohtani E., Tsujimori T., Komatsu K. Retrograde phases of former bridgmanite inclusions in superdeep diamonds // Lithos. - 2020. - Vol.370. - Art.105659. - ISSN 0024-4937. - EISSN 1872-6143.
Внешние системы:	DOI: 10.1016/j.lithos.2020.105659; РИНЦ: 43306486; WoS: 000558896300036;
Реферат:	eng: (Mg,Fe)SiO3 bridgmanite is the dominant phase in the lower mantle; however no naturally occurring samples had ever been found in terrestrial samples as it undergoes retrograde transformation to a pyroxene-type structure. To identify retrograde phases of former bridgmanite single-phase and composite indusions of (Mg,Fe)SiO3 in a series of superdeep diamonds have been examined with electron microscopy, electron microprobe, Raman spectroscopy and X-ray diffraction techniques. Our study revealed that (Mg,Fe)SiO3 inclusions are represented by orthopyroxene. Orthopyroxenes in single-phase and composite inclusions inherit initial chemical composition of bridgmanites. including a high Al and low Ni contents. In composite inclusions they coexist with jefibenite (ex-TAPP) and olivine. The bulk compositions of these composite inclusions are rich in Al, Ti, and Fe, which are similar but not fully resembling Al-rich bridgmanite produced in experiments on the MORB composition.The retrograde origin of composite inclusions due to decomposition of Al-rich bridgmanite may be doubtful because each of observed minerals may represent coexisting HP phases, i.e. bridgmanite or ringwoodite. (C) 2020 Elsevier B.V. All rights reserved.
Ключевые слова:	HETEROGENEITY; PEROVSKITE; JUINA AREA; MATO-GROSSO; DEEP MANTLE; MINERAL INCLUSIONS; LOWER-MANTLE; ALMANDINE-PYROPE PHASE; SUBDUCTED BASALTIC CRUST; Jeffbenite; Lower mantle; Superdeep diamonds; Bridgmanite; TRANSITIONS;
Издано:	2020
Физ. характеристика:	105659