Vesicles in thick komatiite lava flows, Kambalda, Western Australia

Traditionally, vesicles have been considered to be rare in komatiites, howe ver, field studies at Kambalda, Western Australia, and critical literature examination suggest that vesicle presence and content in komatiites are gro ssly underestimated. At Kambalda, vesicles are observed in significant amou nts (up to 30%) in internal horizons within komatiite lavas. The vesicular horizons are inferred to represent bubbles frozen in place below the upper crust, during multiple episodes of flow through of bubble-rich lava. We con clude that vesicle and crystal distribution are compatible with many komati ites being emplaced under laminar flow conditions, analogous to models for basalt lava emplacement.