Reston, VA – The U.S. Geological Survey (USGS) and the Association of American State Geologists (AASG) announced that they have developed an updated geologic time scale and color scheme for use in ...
Introduction / F.M. Gradstein -- Chronostratigraphy : linking time and rock / F.M. Gradstein, J.G. Ogg and A.G. Smith -- Biostratigraphy : time scales from graphic ...
Every half-million years or so, for unknown reasons, the earth’s magnetic field suddenly flips. Within a period of 10,000 years—a mere instant on the geological time scale—the north and south magnetic ...
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