Инд. авторы:	Zedgenizov D.A., Shatskiy A., Ragozin A.L., Kagi H., Shatsky V.S.
Заглавие:	Merwinite in diamond from Sao Luiz, Brazil: A new mineral of the Ca-rich mantle environment
Библ. ссылка:	Zedgenizov D.A., Shatskiy A., Ragozin A.L., Kagi H., Shatsky V.S. Merwinite in diamond from Sao Luiz, Brazil: A new mineral of the Ca-rich mantle environment // American Mineralogist. - 2014. - Vol.99. - Iss. 2-3. - P.547-550. - ISSN 0003-004X. - EISSN 1945-3027.
Внешние системы:	DOI: 10.2138/am.2014.4767; SCOPUS: 2-s2.0-84894548706; WoS: 000331676800033;
Реферат:	eng: Diamonds from Juina province, Brazil, and some others localities reveal the existence of a deep, Ca-rich carbonate-silicate source different from ultramafic and eclogite compositions. In this study, we describe the first observation of merwinite (Ca2.85Mg0.96Fe0.11Si2.04O8) in a diamond; it occurs as an inclusion in the central growth domain of a diamond from the Sao Luiz river alluvial deposits (Juina, Brazil). In addition, the diamond contains inclusions of walstromite-structured CaSiO3 in the core and (Mg0.56Fe0.14)(2)SiO4 olivine in the rim. According to available experimental data, under mantle conditions, merwinite can only be formed in a specific Ca-rich and Mg- and Si-depleted enviroment that differs from any known mantle lithology (peridotitic or eclogitic). We suggest that such chemical conditions can occur during the interaction of subduction-derived calcium carbonatite melt with peridotitic mantle. The partial reduction of the melt could cause the simultaneous crystallization of Ca-rich silicates (CaSiO3 and merwinite) and diamond at an early stage, and (Mg0.86Fe0.14)(2)SiO4 olivine and diamond at a later stage, after the Ca-Mg exchange between carbonatite melt and peridotite has ceased. This scenario is supported by the presence of calcite microinclusions within merwinite.
Ключевые слова:	EARTHS MANTLE; OCEANIC-CRUST; SUBLITHOSPHERIC MANTLE; 6 GPA; DEEP MANTLE; HIGH-PRESSURE; JUINA AREA; CARBONATE-SILICATE INTERACTION; carbon; calcic lithology; Earth's mantle; diamond; Merwinite; PHASE-RELATIONS; MATO-GROSSO;
Издано:	2014
Физ. характеристика:	с.547-550