spatter cone

A spatter cone forms when a limited amount of basaltic lava erupts from an active volcanic vent. The molten rock falls back to the ground in liquid gobs that agglutinate, or weld together. The result is a steep-sided cone up to a few dozen feet high that resembles the sand-drip forms children squeeze from their fists at the beach. If the lava erupts along a fissure, the molten gobs may adhere in a long, narrow heap known as a spatter rampart. Spatter zones sometimes include fragments so molten that they flatten when they hit the ground, called cow pie bombs by geologists. Spatter mounds formed not by active venting but when lava pushes up through an opening in the roof of a lava tube have an equally colorful name: hornito—a diminutive of the Spanish word for oven. The latter sometimes solidify into fantastic globular heaps and spires.

Pamela Frierson