The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in...
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Transcript of The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in...
![Page 1: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/1.jpg)
The Grand CanyonThe Grand Canyon
Megan PickardMegan PickardTESSE 2009TESSE 2009
![Page 2: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/2.jpg)
Law of Original HorizontalityLaw of Original Horizontality• Sediments are deposited in layers that are
horizontal
![Page 3: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/3.jpg)
Law of Superposition:
• In layered sedimentary rocks
• Rocks on bottom are OLDER than rocks on top
• So…
Tapeats Sandstone520 million years oldTapeats Sandstone520 million years old
Kaibab Formation270 million years oldKaibab Formation270 million years old
![Page 4: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/4.jpg)
http://mountaincatgeology.wordpress.com/2009/02/16/unconformities/
ANGULAR UNCONFORMITY
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Volcanic Activity
• Began 630,000 years ago• Last eruption was around 400,000 years ago
One of many cinder cones that sit on top of the youngest sedimentary layer above the Grand Canyon
![Page 6: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/6.jpg)
Lava cascaded over the rim of the Grand Canyon, damming the Colorado River at
least 13 times!
~2540 feet
![Page 7: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/7.jpg)
• So which is older in the Grand Canyon: Basalt or Limestone?
![Page 8: The Grand Canyon Megan Pickard TESSE 2009. Law of Original Horizontality Sediments are deposited in layers that are horizontal.](https://reader035.fdocuments.us/reader035/viewer/2022081603/56649f335503460f94c4f87a/html5/thumbnails/8.jpg)
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http://www.nature.nps.gov/views/layouts/Main.html#/GRCA/geology/
• Uplift of the Colorado Plateau was a key step in the eventual formation of Grand Canyon. The action of plate tectonics lifted the rocks high and flat, creating a plateau through which the Colorado River could cut down.
• The Colorado River has been carving away rock for the past five to six million years. Remember, the oldest rocks in Grand Canyon are 1.8 billion years old.
• The canyon is much younger than the rocks through which it winds• Several factors increase the amount of downcutting that happens in Grand
Canyon: the Colorado River has a steep slope, a large volume, and flows through an arid climate.
• Gradient is a measure of slope. The higher the gradient, the steeper the slope. If you go sledding, a steeper slope means a faster ride down the hill. For riverbeds, a high, or steep, gradient means a faster current. A river with a faster current has the power to carry larger rocks and boulders.
• On its 277 mile (446 km) journey through Grand Canyon, the Colorado River descends about 2,000 feet (610 m) in elevation.
General Geology Notes: