EART 3 Geology of National Parks 22504

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EART 3- Geology of National Parks 2/25/04

• OUTLINE
• Evolution of the Appalachian Mountains
• Reconstructing Past Plate Motions
• National Parks in the Appalachians
• Shenandoah NP
• Great Smoky NP
• Acadia NP
• CONCEPTS
• Plate tectonics and orogeny
• Earths magnetic field and paleomagnetism

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Appalachian Mountains
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Acadia NP Shenandoah NP Great Smoky NP
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1. Piedmont- Precambrian and Paleozoic
metamorphosed rocks of low relief
3. Valley and Ridge- Paleozoic folded and faulted
sedimentary rocks
2. Blue Ridge- Precambrian and Cambrian
metamorphosed rocks and granites thrust over
Valley and Ridge to the west- high relief
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Geologic History of the Appalachian Mountains-
Colliding and Rifting Continents

• Precambrian
• 1. N. America, Africa, Asia and Europe collide
  to form a super continent METAMORPHISM
• 2. Super continent rifts apart forming
  proto-Atlantic Ocean (Iapetus)
• FORM BASALTS
• 3. Tensional rifting forces change to
  compression and subduction BUILD ANDESITIC
  VOLCANIC CHAINS
• Paleozoic
• 1. Taconic Orogeny- collision of andesitic
  volcanic chain with N. America DEFORMATION,
  METAMORPHISM, MAGMATISM
• 2. Acadian Orogeny- Avalon terrane collides with
  northern coast of N. America DEFORMATION,
  METAMORPHISM, MAGMATISM
• 3. Alleghenian Orogeny- all continents collide
  to form super continent called Pangea
  DEFORMATION, METAMORPHISM, MAGMATISM

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VIDEO
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Thrust faults moved Precambrian rocks 150 miles
westward
Metamorphosed basalt
Paleozoic sedimentary rocks
Gneiss and granite
More intense deformation at Great Smoky than
Shenandoah
Precambrian sedimentary and metamorphic rocks