sp10_11a_106_Impacts

sp10_11a_106_Impacts - Impacts from Above 50,000 yr old...

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Impacts from Above Watching the skies for potential catastrophes 50,000 yr old Meteor Crater, AZ Mass Extinctions: Death and Destruction
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Five Big Mass Extinctions When (End of…) Species Loss** Major Loses to ~440 Myrs Ordovician 85 ±3% Brachiopods & bryozoans ~360 Myrs Devonian 83 ± 4% Rugose & tabulate corals, armored* & jawless fish 251 Myrs Permian 95 ± 2% All life! - Trilobites*, corals*, blastoids* 205 Myrs Triassic 80 ± 4% Most synapsids 65 Myrs Cretaceous 76 ± 5% Dinosaurs, marine reptiles, ammonites* *Went extinct, **From Jablonski (1991,1995) Causes of Mass Extinctions Major and rapid environmental change - to fast for species to adapt Such as: Meteorite impacts Massive global eruptions Rapid climate change Major sea level fluctuations Nearby supernova event Ultimate Natural Disasters
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Case Study in End Times: K-T Extinction 65 Million yrs ago 10 km rocky object Evidence Iridium Shocked Quartz
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The Impact Site 180 km What Happened? Global Effects 1. Darkness - decrease in photosynthesis 2. Cold (2-3 Months of -20°C) 3. Followed by Greenhouse warming 4. Acid Rain 5. Wild f res 6. Toxic Seawater Immediate Area 1. Tsunami & Fallout 2. Total destruction
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More Recently, 1994: Comet Shoemaker-Levy At least 21 fragments (2km) Large Impacts What is out there - what could hit us? What types of things hit us? What happens when they hit us? What do we do to prepare? How do we watch for potential objects?
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This note was uploaded on 01/11/2012 for the course GEO 106 taught by Professor Robviens during the Spring '10 term at Bellevue College.

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sp10_11a_106_Impacts - Impacts from Above 50,000 yr old...

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