Petit-spot volcanoes scraped off into accretionary wedge

Abstract

New of the mechanisms by which magma reaches the Earth's surface is ascent along brittle fractures that develop where plates flex due to subduction and/or loading by seamounts, thereby forming a swarm of small knolls termed "petit-spots". The widespread occurrence of this process is supported by the reinterpretation of the origin of alkaline basalts found within accretionary prisms.