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Printer-friendly version The Earth's magnetic field occasionally undergoes a spontaneous reversal in which the north and south poles switch places. The mechanism of reversals are still not completely understood, although simulations on supercomputers have been able to reproduce them. These reversals happen very fast geologically speaking; we know this because we don't find much evidence of rocks preserving evidence of an intermediate field where the poles are in the middle of their reversal path.
Un article de Wikipédia, l'encyclopédie libre. La géologie est la science qui étudie la Terre dans ses différentes parties directement accessibles à l'observation, s'efforçant de reconstituer leur histoire par l'étude de leur agencement.
Search the Following Databases These databases are part of the Geolbases Collection , available for purchase on CDROM. The online versions are free to use. They have a simpler search interface and generally fewer features/information/data than the Full Versions.
The GeoRef database , established by the American Geosciences Institute in 1966, provides access to the geoscience literature of the world. GeoRef is the most comprehensive database in the geosciences and continues to grow by more than 100,000 references a year. The database contains over 3.4 million references to geoscience journal articles, books, maps, conference papers, reports and theses.