Taragai Peridotite Massif as an Explosive Pipe in the Western Bureya Terrane (Southern Russian Far East)

Abstract

Taragai peridotite massif is interpreted as an explosive ultramafic pipe emplaced through the Neoproterozoic carbonate skarnoids and Early Paleozoic granites of the western Bureya terrane. Peridotites at the surface are represented by strongly eroded bowl-shaped structure filled with disintegrated explosive material containing abundant peridotite boulders and host rock xenoliths. Explosive character of the Taragai massif is further emphasized by the occurrence of magnetite, iron-carbonate-silicate (with magnetite) and Cu-Ag-Au microspherules characteristic of explosive eruptions. Formation of the Taragai ultramafic pipe is related to the assimilation of mantle wedge or lithospheric mantle material over the stagnant Izanagi slab by the ultra-hot and reduced upwelling fluid flow within the transform-type continental margin tectonic setting.