The growth and formation of young (Quaternary) ocean islands volcanoes is often governed by episodic build up (volcanic eruptions) and destruction (landslides or collapsing of part of the volcano flank). The mega-tsunamis that can be triggered by flank collapses could result in ocean-wide destruction, and constraining the age and frequency at which flank collapses occur is therefore of fundamental importance. The processes leading up to, and actual flank collapse itself, are poorly understood with internal (changes in magma chamber systematics, shift in stress field, gravitational instability, etc) and external (changes in climate, sea-level, groundwater table, etc) processes proposed. The lack of understanding follows directly from the absence of absolute age constraints. Conventional dating methods (e.g., radiocarbon and 40Ar/39Ar) are often insufficient as rocks lack suitable material (charcoals) or are too young to be dated precisely. We propose two alternative dating methods, namely cosmogenic 3He exposure dating on olivines and pyroxenes as well as (U-Th)/He dating on apatite, zircon and titanite. The unparalleled time scales at which these combined methods can be applied will shed important new insights in the Quaternary growth history and destruction of ocean island volcanoes.
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