Lava Lake

When lava ponds up in a passage it cools to form a smooth-surfaced lake. Typically the ponding occurs in plunge pool basins eroded beneath lavafalls, as seen in the first photo. They may also occur when flows have been backed up by constrictions downstream of the flow due to passage collapse, which is probably what formed the now-drained lake in the second photo. Here the center of the lake’s surface collapsed, leaving broad shelves along each side.

AUTHOR: Dave Bunnell