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Geologic Processes

Geologic Processes

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Geologic Processes

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  1. Geologic Processes

  2. Geological Processes • Tectonics • Rocks bend and break (folding and faulting). • Volcanism • Rocks melt and explode. • Erosion and surface processes • Surfaces flatten out: mountains crumble and holes are filled in. • Mass wasting (gravity action) • Wind action • Water action • Impact Cratering (external) • Bodies from space hit the ground, making a hole.

  3. Tectonics -Folding • When rocks are squashed they will compress and bend away from the direction of maximum pressure

  4. Folding in the Andes Mtn.s, S. America

  5. Wrinkle Ridges on the Moon • Cooling rocks contract, the shrinkage causes folding and ridges form

  6. Ridges on Europa

  7. Tectonics -Faulting • Extension Faults -crust moves apart, makes a larger area. • Compression Faults -crust moves together, makes smaller area. • Strike-slip Faults -crust moves sideways, no gain or loss of area

  8. Volcanism Rocks melt and explode

  9. Generic Volcano Structure

  10. Volcanic Processes • Rocks melt and explode. • 2 components: lava, gasses • Lavas - variable viscosity,depending on chemistry • Low viscosity range of viscosity High viscosity (runny lava) (gooey, sticky lava) Low gas content High gas Result: Result: Low broad shapes range of volcanoes Tall cone shapes Volcanic Shield Cinder Stratovolcanoes Floods Volcanoes cones

  11. Volcanic Floods -VERY low Viscosity

  12. Hawaiian Effusive eruption

  13. Shield Volcano

  14. Shield Volcano’s Cauldera

  15. Olympus MonsMartian Shield Volcano • Note the broad shield shape and the central cauldera

  16. Cinder Cones- SP Crater, Arizona

  17. Cinder Cones- SP Crater, Arizona

  18. Stratovolcanoes

  19. Mayon Stratovolcano, Phillipines

  20. Mt St Helenspre-1980 eruption 1986 eruption

  21. Mt St Helens More tytpical eruption Oct 1st & 5th 2004

  22. Many cities are built below stratovolcanoes e.g Seattle and Mt Rainier

  23. This eruption from Mt Etna in 1983 shows lava flows engulfing the tourist facility.

  24. Soufrière Hills, Monserrat 1995 Southern half of island evacuated and capital city lost

  25. Alternative Materials: Carbonatites

  26. Alternative Materials: Sulfur • Spacecraft observe live sulfur volcanoes on Io

  27. Erosion and Surface Processes • Surfaces flatten out: mountains crumble and holes are filled in. The processes that carry out erosion each show characteristic patterns: • Mass wasting (gravity action)- land slides • Wind action- sand dunes, wind streaks • Water action- river channels, ocean shores, glacial erosion

  28. Mass Wasting on the Asteroid Eros

  29. Sand Dunes in the Sahara (imaged by the Space Shuttle)

  30. Sand Dunes in the Namib (imaged by the Space Shuttle)

  31. Sand Dunes on Mars

  32. Sand Dunes on Mars

  33. Wind Streaks on Venus

  34. Water Channels on Mars

  35. Water Channels on Mars

  36. Cape Cod, Earth • Material is carried to the oceans and dumped. • Gains are ground up by pounding waves. • THIS IS UNIQUE TO EARTH

  37. Impact Cratering • Bodies from space hit the ground, making a hole. (the only external process -it comes to the planet from the outside) • The size of the hole depends on the energy of the impact. • A small, slow-moving, ice-ball makes a small hole. • A massive, fast moving, rock makes a large hole.