Sinks of Liquid Immiscibility in Ongonitic Magma: Evidence from the Study of Melt and Fluid Inclusions in Rocks of the Ary-Bulak Massif (Eastern Transbaikalia)

摘要

Rocks of the Ary-Bulak ongonite massif are outcropped as an elongated submeridional ellipsis with a size of ～500 × 800 m. The massif has a mushroomlike shape with a maximal horizontal section beneath Quaternary deposits of ～700 × 1500 m and gentle slopes (35°-12°) relatively to the host sedimentary-volcan-ogenic rocks (J_3-K_1), namely schists and basic effusive rocks [1]. Porphyric ongonite composing a large part of the massif is gradually replaced by aphyric rocks on the southwestern flange within the marginal zone with a thickness of up to 100 m.