Basalt Samples from a Lava Flow
Samples of fresh basalt were collected from Axial Seamount's caldera floor. When fresh, the outer surface of the rock is glassy due to the very rapid cooling and crystallization that occurs when the hot lava comes in contact with the 2oC seawater. This glass – known as obsidian – is very sharp and crumbles easily. (Photos by Leslie Sautter)
July 31, 2013