National Geographic : 1960 Oct
1,500 years old now. This means that the lava here must be at least 1,650 years old, allowing time for the lava to cool and for soil to accu mulate in a crack so a seed could take root." Heaps of contorted clinkers don't sound inviting, but they make an attractive camp ground at Craters of the Moon. Tent and trailer spaces are smoothed between the lava flows, with scattered trees adding friendly touches of shade. The climate at 5,900 feet is pleasantly cool and dry. Cinders Rise Like Dead Volcanoes The biggest things around are the cinder cones. The fiery fountains that created them sprayed lava froth high into the air, where it congealed into pebble-sized molten particles that flew far and cooled before landing. These particles, called cinders even though they never burned, remained separate and are now piled in black, loose heaps, each heap looking like a dead volcano. 510 "Our largest cinder cone is 760 feet high," Peter Sanchez, a park ranger-naturalist, told us. "That means the fountain must have shot up about 1,000 feet." Cones of another type, the spatter cones, grew out of less powerful fountains. Their lava flew more slowly and less far, and did not cool as much before landing. It came down in gummy blobs that stuck together. Hence the steep, craggy sides of the typical spatter cone. The biggest one we saw was about 50 feet high. In some eruptions the magma did not shoot into the air at all, but welled out slowly, forming a solid, broad mound 30 to 50 feet high, called a lava dome. Elsewhere the lava had welled up, congealed on the surface, and then receded, leaving a hollow space; when the thin crust collapsed, it left pit craters, or "sinks," with jagged rims. Pete showed us minor volcanic forms, too called volcanic bombs.