Could magnetic reversals be caused by meteorite or comet impacts?
Although extremely unlikely, it might be possible for a reversal of the Earth's magnetic field to be triggered by a meteorite or comet impact, or even for it to be caused by something more "gentle," such as the melting of the polar ice caps.
Self-contained dynamic systems like Earth’s dynamo can have reversals without any outside influence. Reversals of Earth's magnetic field can simply happen.
Learn more: USGS Geomagnetism Program
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Tiny Teeth Forecast Ancient Comet Showers
Minuscule fossil animal teeth, known as conodonts, indicate that a 370-million-year-old comet that slammed into southern Nevada could be as much as five times larger than scientists initially suspected.
Comet that triggered mass extinction was much larger than originally thought...
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An extraterrestrial object, theorized to be a comet at least one kilometer in diameter, impacted what is now southern Nevada about 370 million years ago.
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Cratered cones near Hephaestus Fossae, Mars. This might look at first glance like a cinder cone, but it is more likely an impact crater. Using the shadow, one can tell that its floor is at a lower elevation than the surrounding landscape. A cinder cone would rise above the landscape.
Cinder cones (otherwise known as scoria cones) are the most common type of volcano
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PubTalk 3/2007 — Impact!
Piecing together the story of a giant meteorite crater beneath the Atlantic coast
By David S. Powars, Geologist, and R.D. Catchings, Geophysicist
- Buried under Chesapeake Bay is a very well preserved impact structure 56 miles across and more than 2 miles deep
- Following clues from drill holes and seismic imagery, careful
PubTalk 7/2004 — Secrets in Stone
The Role of Paleomagnetism in the Evolution of Plate Tectonic Theory Video Presentation
Presentation of the award-winning USGS video "Secrets in Stone" (35 minutes), introduced by Jack Hillhouse, Research Geophysicist, and followed by a tour of the USGS Paleomagnetics Laboratory
- Crucial discoveries in the early 1960.s were made
Chart showing the Earth’s magnetic feild
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