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

2. 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

3. 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.

4. Forces In The Earths Crust Folds Folds that are concave upward are called synclines. Syncline Folds that are convex upward are called anticlines. Anticline Source: Georgia Perimeter College Geology 101 http://www.gpc.edu/~pgore/geology/geo101/folds.htm

5. Forces In The Earths Crust Folds Source: www.geology-israel.co.il/WEB%20PAGE/folds-1.jpg

6. Forces In The Earths Crust Folds- Slide Show University of North Dakota: Geology 101 http://www.und.nodak.edu/instruct/mineral/101intro/s lides/folds/slide1.htm