|Breakdown may occur before
or after a tube has drained and cooled. When it occurs during the cooling
phase, breakdown falling onto a partially cooled floor may by welded to
it by "segregations," material boiling out of the semi-solid floor matrix.
Breakdown may also occur after a tube has cooled, but then be overflowed
by a subsequent lava flow that forms a coating and "welds" it together
or on to the floor.
Breakdown may also be moved downflow with the stream of lava before being emplaced, especially if its specific gravity is less than the molten lava on which it floats. As it moves, it may roll along and accumulate molten lava, becoming a lava ball.
|Created: August 4, 2000
Author: Dave Bunnell