Raise Some Glass

Glassy, angular fragments of volcanic rock provided key evidence that volcanoes on the Arctic Ocean floor have exploded violently, defying the common assumption that there is too much pressure and the rock is too cold and slow-moving for a pyroclastic eruption in the deep. Such fragments are typically formed when steam and carbon dioxide gas build up inside volcanoes to produce explosions.
(Photo by Adam Soule and Claire Willis, Woods Hole Oceanographic Institution)