Impacts - ONLY WILDFIRE QUESTION ON FINAL- Lodgepole pine-...

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ONLY WILDFIRE QUESTION ON FINAL - Lodgepole pine- why wildfires are good- trees cant reproduce until a wildfire burns outside- require fire in order to open pine shells and flourish- common tree out in west- unfortunately because of drought has stressed trees and pine beetles causes more destruction. Impacts of Asteroids and Comets The Ultimate Catastrophe? 0. Asteroid 10-15 km in diameter struck Yucatan peninsula of eastern Mexico, 65 million years ago (end Cretaceous—known as KT boundary)- being used to say why dinosaurs possibly died 1. Formed Chicxulub crater 80-110 km in diameter- underground- discovered it drilling for oil- high iridium content in rock- when it comes in ocean forms tsunami wave 2. Crater walls collapsed to form 195-km crater basin with central uplift 3. Asteroid impact finished off the dinosaurs as well as majority of other species on Earth 4. Energy equivalent to 1 million 1980 eruptions of Mount St. Helens 5. Crater was later buried by limestone layers and is no longer visible at surface 6. Record of impact is preserved in sedimentary deposited at that time around world 7. K-T boundary rocks contain shocked quartz grains, extremely high pressure silica mineral coesite, glass spherules 8. Huge tsunami waves left debris 50-100 m above sea level around Gulf of Mexico Projectiles from Space 9. Asteroids, comets and meteors cross Earth’s path 10. Asteroids and comets are known as bolides Asteroids are chunks of rock that did not coalesce into planet when solar system formed 11. Some asteroids are pulled out of normal orbits by collisions or gravitational influence of sun and planets 12. Difficult to spot if on trajectory toward Earth 13. Majority are less than 3 km in diameter, most between 100 meters and 1 km diameter Comets consist of ice and some rock: dirty snowballs 14. Come from Oort cloud – vast spherical region extending more than 100,000 times Earth’s distance from sun, containing billions of comets 15. Kuiper comet belt lies in plane of solar system, extending to 20,000 times distance from Earth to sun and contains trillions of comets 16. Comets travel up 60-70 km/s, making impacts catastrophic
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This note was uploaded on 02/21/2010 for the course GEOL 116 taught by Professor Kruger during the Spring '09 term at Binghamton University.

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Impacts - ONLY WILDFIRE QUESTION ON FINAL- Lodgepole pine-...

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