Basaltic pillars in collapsed lava-pools on the deep ocean floor

Observations of peculiar volcanic objects, made by a submersible on the deep sea floor at a depth of about 2.600 m at and near the axis of the East Pacific Rise during the CYAMEX expedition as part of the RITA Project are presented here. Two basic types of flow forms were observed within the crestal area of the East Pacitic Rise : pillow flows and fluid lavas, the latter sometimes overlying massive flows. The East Pacific Rise at 21°N comprises an axial, unfaulted extrusion zone bordered by an extension zone chararterised by faulting. Pillow flows occupy the innermost or extrusion zone and constitute small elongated volcanic highs. [NOT CONTROLLED OCR]