xOoids : Small (< 2 mm), spheroidal, layered sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals.
Geologists have learned that a magnitude-8.1 earthquake and tsunami that killed 192 people on September 29, 2009 in Samoa, American Samoa and Tonga was in fact a triple-whammy. The 8.1 "great earthquake"...Read more