Submarine lineated sheet flows: a unique lava morphology formed on subsiding lava ponds

Lineated sheet flows are flat-lying, glassy lava flows characterized by a r egular surface pattern of parallel grooves or furrows aligned with the flow direction. They are unique;to the submarine environment. We propose that t he lineations are developed within the collapsed interiors of partially pon ded lobate sheet flows that initially inflate and then drain out during emp lacement, During lava drainout, the original lobate crust founders and a ne w crust begins to grow on the subsiding lava surface. Lineated now texture is created where molten lava emerges laterally from beneath a growing crust . The Lineations are formed by raking of the emerging lava surface by irreg ularities on the bottom edge of the crust and are preserved owing to rapid chilling by seawater. Therefore, lineated sheet flows are the product of a specific sequence of events over a short period of time during the course o f a deep submarine eruption.