Forces and their effect. Two main forces is rock stress and rock strain.Rock stress are the forces that can act at the earth's surfaceRock strain is the effect on the rocks or a change in the shape of the rocks a result of the stress. Stress. Stress is the force applied to rocks due to moving of t
1. Folds and Faults
2. Forces and their effect Two main forces is rock stress and rock strain.
Rock stress are the forces that can act at the earth’s surface
Rock strain is the effect on the rocks or a change in the shape of the rocks a result of the stress
3. Stress Stress is the force applied to rocks due to moving of the Earth’s plates.
There are 3 types of stress:
Compression – forces from opposite directions that push on one another
Occurs at converging plates; rocks generally thicken and shorten
4. Stress Tension – pulling forces in opposite directions which results rocks thinning, lengthening, breaking
Occurs at diverging plates; very rare form of stress
5. Stress Shearing – parallel forces but moving in opposite directions
Occurs at transform plate boundaries
Faults occur under shearing forces
6. When anything is subjected to a force, that object is deformed due to the stress.
Various impacts on rock depending if rock is elastic, brittle or ductile
7. Deformation Characteristics of Rocks A rock that is elastic can deform in any direction then spring back to its original shape
A rock that is brittle breaks or fractures under stress
Rocks that are ductile bend under stress and do not return to there original shape
8. Folds Folds are bends or wavelike features in layered rock
Ductile rocks fold due to compression at convergent plates
The most common types of folds are tightly folded peaks and troughs.
The peaks are called anticlines.
The troughs are called synclines.
9. Anticlines and Synclines