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A Paleogeographic Reconstruction of Impact Craters

A Paleogeographic Reconstruction of Impact Craters. April 19, 2008 Catherine Juranek Dr. David M. Best. Earth’s Geology. 4.6 billion years old Plate tectonic movement Arizona has moved through 65° latitude in past 500 million years [20°S to 45°N] 174 extraterrestrial impacts.

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A Paleogeographic Reconstruction of Impact Craters

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  1. A Paleogeographic Reconstruction of Impact Craters April 19, 2008 Catherine Juranek Dr. David M. Best

  2. Earth’s Geology • 4.6 billion years old • Plate tectonic movement • Arizona has moved through 65° latitude in past 500 million years [20°S to 45°N] • 174 extraterrestrial impacts Photo courtesy of: Dr. Ron Blakey, NAU

  3. 8 impacts Density: 1/861K mi2 19 impacts Density: 1/614K mi2 South America & Africa Photos courtesy of: The Planetary and Space Science CentreUniversity of New BrunswickFredericton, New Brunswick, Canada

  4. 27 impacts Density: 1/635K mi2 26 impacts Density: 1/114K mi2 Asia & Australia Photos courtesy of: The Planetary and Space Science CentreUniversity of New BrunswickFredericton, New Brunswick, Canada

  5. 37 impacts Density: 1/108K mi2 57 impacts Density: 1/167K mi2 North America & Europe Photos courtesy of: The Planetary and Space Science CentreUniversity of New BrunswickFredericton, New Brunswick, Canada

  6. Paleomapping Software • PointTracker • Plots current impact positions in terms of paleolocations in past geologic time • PlateTracker • Moves plates back in geologic time to focus PointTracker locations • ARCGIS • Mapping tool

  7. Results • No correlation

  8. Results • Youngest/oldest correlation

  9. Results • 26 of 31 youngest are the smallest

  10. Results • Unprocessed data points • 33 craters < 10 million years old • 13 craters > 600 million years old

  11. Results • Correlation: Younger – north Older - south

  12. Conclusions • 26 of 30 youngest craters are the smallest • Ancient Earth atmospheric effect • Size of extraterrestrial bodies over time • Erosion of older smaller craters

  13. Conclusions • Correlation between latitude and age • Division at 310 million years • 62% older craters in southern latitudes and 85% younger craters in northern latitudes • Possible explanation: shift of land masses • Does not explain latitudinal differences in South America and Africa

  14. Challenges • No record of oceanic impacts • Software restrictions • Posit processing limited to 10-600 my only • Posits 10-100 myo rounded to nearest 10 my • Posits 100-600 myo rounded to nearest 20 my • Graphing and mapping options

  15. What’s in the Future? • Further Analysis • Comparison with terrestrial/marine boundaries • Spatial analysis of impacts • Using nearest neighbor statistics • Determine random vs clustered patterns

  16. Africa and South America – The FIT Photos courtesy of: The Planetary and Space Science CentreUniversity of New BrunswickFredericton, New Brunswick, Canada

  17. What’s in the Future? • Possible Connections • Theory of antipodal focusing • Astronomical implications • Evidence of asteroid storms • Asteroids impacts as further proof of plate tectonics

  18. Questions • ??????????

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