Deep in the heart of a lava flow

March 17th, 2011

ZZYZX, CALIFORNIA–This morning the Wooster Geologists enjoyed an ancient lava flow from the inside. We found our way to a lava tube near the center of the Mojave National Preserve and explored the interior with flashlights and flash cameras. It helped that there were a few “windows” in the basalt roof where sunlight could stream in. As Meagen Pollock (she who lives for basalt) explained, a lava tube is formed when a flow cools on its exterior portions while the lava is still moving.  When the lava drains out at the end of the flow, the result is a long tunnel of basalt.  Lava dripped from the ceilings, making the igneous equivalent of stalactites.  As the flow receded, it left horizontal “bath tub rings” along the side of the tube. It was fun to speculate on how many lava tubes remain undiscovered beneath the many square kilometers of basalt exposed in the Mojave Desert.

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