GeoLogic Mapping is a Division C event that returned for the , and seasons. It was previously in rotation from , and was introduced as a trial event in New York in the season. This event tests competitors' knowledge of structural geology, geologic history, map reading, and related topics. GeoLogic Mapping requires that students be proficient in both reading and constructing topographic maps, geologic maps, geologic cross sections usually depicted as layers and other projections. A working knowledge of Earth history is also necessary, with more in-depth review of tectonics, rock formation, lithologies, and geologic principles.
Eon , Long span of geologic time. In formal usage, eons are the longest portions of geologic time era s are the second-longest. Three eons are recognized: the Phanerozoic Eon dating from the present back to the beginning of the Cambrian Period , the Proterozoic Eon , and the Archean Eon. Less formally, eon often refers to a span of one billion years.
Carbon dating , also called radiocarbon dating , method of age determination that depends upon the decay to nitrogen of radiocarbon carbon Radiocarbon present in molecules of atmospheric carbon dioxide enters the biological carbon cycle : it is absorbed from the air by green plants and then passed on to animals through the food chain. Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food. Once the organism dies, however, it ceases to absorb carbon, so that the amount of the radiocarbon in its tissues steadily decreases.