[S-CG54] New Insights of Fluid-Rock Interactions: From Surface to Deep Subduction Zone

[SCG54-P19] Petrological and geochemical features of jadeitite from the Voikar-Syninsky ultramafic complex, the Polar Urals

Yui Maeda¹, *Satoko Ishimaru¹, Makoto Miura², Shoji Arai³, Vladimir R. Shmelev⁴ (1.Department of Earth and Environmental Science, Kumamoto University, 2.GIA, 3.Kanazawa University, 4.Zavaritsky Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences)

Keywords:jadeite, Polar Urals, mantle wedge, slab fluid

We described petrological and mineral chemical features in Voikar-Synisky jadeitite, the Polar Urals. We collected 9 jadeitite samples and most of them are white but some are greenish. Most of them are mainly composed of clinopyroxene (jadeite and omphacite) (≈ 80 vol.%) with minor amounts of amphiboles (Ca-Na amphibole and Ca amphibole), biotite, natrolite, pectolite, and titanite. Jadeite is euhedral and subhedral, and some samples contain radial aggregates of jadeite/omphacite. Green samples contain chromian spinel and the clinopyroxene around the chromian spinel is omphacite, which contains high amounts of Cr₂O₃ (up to 6 wt.%). It is noteworthy that the presence of high-Sr minerals (Sr-apatite, Sr-carbonate, and niigataite). The trace element composition of the jadeite (Miura et al., 2019) is similar to that of jade pyroxene from the Itoigawa-Omi area, which is considered P-type jadeite. The mineral combination and chemical composition suggest that it was directly crystallized from slab-derived fluids within mantle wedges.