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Asteroid belt

Asteroid belt. Kuiper Belt and Oort Cloud. IMPACT EVENTS. Known impact craters. http://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Animation.gif. Barringer Meteor Crater, AZ (49,000 yrs). Manicouagan Crater, Canada (~212 Ma). 100 km. Clearwater Lakes, Canada (~290 Ma).

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Asteroid belt

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  1. Asteroid belt

  2. Kuiper Belt and Oort Cloud

  3. IMPACT EVENTS

  4. Known impact craters

  5. http://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Animation.gifhttp://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/Animation.gif

  6. Barringer Meteor Crater, AZ (49,000 yrs)

  7. Manicouagan Crater, Canada (~212 Ma) 100 km

  8. Clearwater Lakes, Canada(~290 Ma)

  9. Chesapeake Bay Crater (35 Ma)

  10. Chicxulub Crater, Mexico(65 ma)

  11. Map of Cenotes

  12. Global Effects • Dust in the atmosphere • Too dark to see for 1-6 months • No photosynthesis for 2 months to year • Drop in land surface temperatures • Carbonates and evaporites vaporized into sulfur gases and CO2 (with resulting acid rain • Massive forest fires (evidenced by charcoal and soot deposits)

  13. http://www.lpl.arizona.edu/SIC/news/chicxulub2.html

  14. Mass Extinctions

  15. Causes of Mass Extinction • Changes in seafloor spreading rates • Causes flooding of land • 110-85 Ma, sea level was over 200 m higher than today • Shallow seas doubled, land mass reduced, warmer climate • Sea level changes from glaciation

  16. Causes (continued) • Number and sizes of continents • More continents can generate new species • Less continents can cause competition for space and niches • Continental position (near or away from poles) • Volcanism • Lava can displace ocean water • Expels atmospheric gases • Ocean composition • Circulation changes can cause anoxic bottom water • Salinity changes from glacial meltwater runoff or excessive evaporation

  17. Causes (continued) • Extraterrestrial • Impact events • Excessive radiation (weakened magnetic field) • Biological • Random extinction • Predation or disease

  18. Permo-Triassic Extinction(~250 Ma) • Formation of Pangaea (reducing area of tropical seas) • Sea level fall from slower seafloor spreading (less overall sea area) • Climate change (drier interior of continents) • Cold ocean water disappeared and no sinking for circulation • Siberian Traps flood basalts (700,000 cubic miles

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