Unit 9 Geology

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Unit 9 Geology
2013-03-31 23:25:14
glaciers geology movement

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  1. What two "Texas geologic features" have formed since the last Ice Age?
    • At the last Ice Age time, the GOM shoreline was almost 50 miles eastward of the present coast of Corpus Christi (425 feet lower than today). Nueces Bay then was a wide river valley.
    • The melting of the continental ice returned water to the oceans. Padre Island formed in step (moving landward) beginning about 1800 years ago
  2. How many miles East of Corpus Christi was the GOM shoreline during the last ice age?
    Almost 50 miles Eastward.
  3. Which other planet, besides Earth, has polar ice caps?
  4. How often (in over 130 years) has Corpus Christi had +4 years inch snows in one-two days?
    Only once for one day in 1895.
  5. How often do snow flurries occur in the Corpus Christi area, according to our local weather station?
    Corpus Christi receives at least a few snow flurries every 2 years, with the earliest being Oct. 1993.
  6. Compare the differences between hail and sleet.
    • Hail is pellet sized ice grains to large balls of ice formed within thunderstorms. 
    • Sleet is frozen raindrops  that do not stick to the ground upon impact, but bounce.
  7. Which condition result in freezing rain? (Contrast to sleet)
    Falls on a surface that has temperatures below freezing which then forms a coating of ice.
  8. What is "black ice"?
    A layer of ice that coats roadways and makes it almost impossible to drive.
  9. Which temperature conditions are necessary for frost to form in the Corpus Christi area?
    When water vapor from the air condenses at a temperature below freezing.
  10. What is a glacier?
    System of moving (flowing) ice that forms where more snow and ice accumulates each year than melts.
  11. How many glaciers form over the sea?
    Sea ice does not form glaciers because the ice cannot get thick enough.
  12. What fraction of an ice mass is below seawater for an average iceberg?
    7/8th of an iceberg mass is found hidden below water.
  13. Which moon of Jupiter shows clear evidence of past icebergs?
  14. What is the difference between a "white out" and a "blizzard"?
    • White out is an ice fog.
    • Blizzard is a severe snow storm.
  15. How much snowfall generally equals an inch of rain?
    Generally it takes from 10" to 12" of snowfall to equal one inch of rainfall
  16. What is a common English name for the firn or neve?
    Snow cyrstals.
  17. What are the two major classifications of glaciers?
    • Valley (Mountain or Alpine) Glaciers
    • Continental Glaciers
  18. What thickness must mountain ice obtain to form a glacier?
    About 60 feet.
  19. What process works with ice skates to make skating easier?
    Basal slips or basal movement where glacial movement accompanied by melting and thawing of the ice near its basal contact with bedrock.
  20. Compare the zone of accumulation with the zone of wastage (ablation) along a glacier. 
    Zone of accumulation has a net gain of ice. Whereas zone of wastage as a net loss.
  21. In regards to glaciers, what is the firn limit or snowline and does it always stay in the same location?
    "Boundary" between zone of accumulation and zone of wastage.
  22. What is a glacial moraine?
    Mounds of ridges of sediment and rocks pushed and deposited at the leading edge of moving glaciers.
  23. What physical conditions create crevasses within a glacier?
    Cracks or opening on top of glacier where it descends over extremely steep slopes or curves.
  24. What are glacial striations?
    Everything from small to large scratches and grooves that have been abraded into the bedrock. These scratches are caused by grinding rocks trapped at the base of an advancing glacier.
  25. What information do glacial striations indicate?
    Glacial striations indicate the direction that the glacier moved.
  26. What causes "U-shaped" valleys in mountain?
    Alpine glaciers. These valleys are scraped out by the bottom of the glacier leaving behind a "rounded" valley (rivers leave a V-shape).
  27. Describe a cirque and how it is formed.
    A bowl-shaped depression produced by glacial plucking at the head of a mountain valley.
  28. How are glacial horns formed?
    Produced by three or more cirques.
  29. Name and give the location of a famous "glacial horns"
    Matterhorne in the Alps of Switzerland.
  30. What thickness of ice must be obtained to form a continental glacier?
    120 feet thick.
  31. What effect would the melting of the Greenland and Antarctica glaciers have on our current sea level?
    Could raise the sea level about 200 ft.
  32. What effect has the weight of all this ice had on parts of the landmass of Antarctica and Greenland?
    Surfaces of some places are 6000 ft. below sea level.
  33. What name do we give the numerous lakes in Minnesota that were created by continental glaciers?
    Kettle lakes.
  34. Describe the "erratic" boulder