Anticlines and Synclines-Class Notes | Jump to: | Types of Folds | Faults | Types of Faults | Guided Student Notes - (Microsoft Word Document) | FoldsWhen rocks are deformed plastically, they are bent into folds: | | | Stress and StrainStress is the applied force (The pushing and pulling on the rock layers).Strain is the bending & twisting that happens to the rock also known as deformation. Stress can be compressional, tensional or shear. | Compressional stress pushes matter (rock layers) together. | Tensional stress pulls matter (rock and dirt layers) apart. | Shear stress is rotational.the stress is parallel to a face of the material, |
All applied stresses cause rock (or any other solid) to deform (strain). Strain can be elastic or plastic. * Elastic strain disappears on the release of the stress. (like a rubber band) * Plastic strain is permanent on release of stress. (like clay)If a material undergoes continuous plastic deformation, it is said to be ductile. If it fractures, it is said to be brittle. | There are Three Main Types of Folds: | Anticlines: This is when layers are folded upwards in what looks like an arch. The layers are symmetrical (look alike) to either side of its center.Rock layers in anticlines dip away from the center axis.The oldest rocks are exposed on the center axis. | |
| Synclines: This is when the rock layers are folded downward.The youngest layers of rock are exposed on the center axis. | | | Monocline: This is when the rock layer has a gently dipping bend in the horizontal rock layer. | | | Faults:
When rocks are deformed (broken) brittly, they are displaced along fractures called FAULTS. | | | Breaks in rock are put into two categories (groups). | Fractures:
When there is no movement along either side of the rock break. | Fault:
When either side of the rock break moves in opposite directions. | | | FAULT TERMINILOGY1) "Hanging Wall"-