Forces In The Earths Crust

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Forces In The Earths Crust
Folds are usually formed when rocks are squeezed
together by compressive forces.
An excellent example of a folded mountain belt is
the Atlas Mountain system of northwest Africa.
Source NASA Goddard Space Flight Center
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Forces In The Earths Crust

• Folding vs. Faulting
• Temperature and time determine whether the rock
  becomes a fold or a fault.
• Rocks in the upper parts of the earths crust have
  lower temperatures.
• Tend to deform by fracturing to form faults
• Rocks in lower parts of the earths crust have
  higher temperatures.
• Tend to deform by changing shape continuously
  to form folds

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Forces In The Earths Crust

• Folding vs. Faulting
• Temperature and time determine whether the rock
  becomes a fold or a fault.
• If a force builds up very fast rocks are more
  likely to fracture.
• If a force builds up very slowly the rock is more
  likely to change shape without breaking.

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Forces In The Earths Crust
Folds
Folds that are concave upward are called
synclines.
Folds that are convex upward are called
anticlines.
Syncline
Anticline
Source Georgia Perimeter College Geology 101
http//www.gpc.edu/pgore/geology/geo101/folds.htm
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Forces In The Earths Crust
Folds
Source www.geology-israel.co.il/WEB20PAGE/folds
-1.jpg
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Forces In The Earths Crust
Folds- Slide Show
University of North Dakota Geology
101 http//www.und.nodak.edu/instruct/mineral/101i
ntro/slides/folds/slide1.htm