Q2 L4

• What happens to rocks and large masses when they undergo deformation?

  They change their shape, location, size, tilt, or break due to stress.
• What is stress in the context of earth science and geology?

  Stress is the force per unit of area that is placed on a rock.
• What type of stress occurs when rocks or plates are pulled apart?

  Tensional stress.
• Where can tensional stress be found?

  At divergent boundaries.
• What is the opposite of compression stress?

  Tensional stress.
• What does compressional stress cause rocks to do?

  It causes rocks to fold or fracture.
• Where does compressional stress occur?

  At convergent plate boundaries.
• What is shear stress?

  Shear stress occurs when forces slide past each other in opposite directions.
• What type of boundaries are associated with shear stress?

  Transform boundaries.
• What is confining stress also known as?

  Lithostatic pressure.
• What does confining stress do to rocks?

  It exerts pressure equally in all directions on a rock.
• How do rocks behave under confining stress?

  They deform ductilely rather than fracture.
• What is the result of tensile stress on rocks?

  Rocks stretch and ultimately fracture or thin.
• What are rift zones an example of?

  Resultant structures from tensile stress.
• What happens to rocks under compressional stress?


  They shorten and deform.
• What can occur through folding in rocks?

  Layers of rock can bend and buckle.
• What is an example of a resultant structure from compressional stress?

  The Himalayas folded mountain ranges.
• What behavior characterizes shear stress?

  Rocks slide past each other or tear along a plane.
• What is an example of a resultant structure from shear stress?

  The San Andreas Fault in California.
• What type of stress did Seff exert on the clay bar?

  Compressional stress.
• How will the clay bar behave after the application of compressional stress?


  The clay bar will fold.
• What kind of stress caused mountains to form when two plates collided?

  Compressional stress.
• What is strain in the context of rocks?

  Strain is the change in a solid's shape caused by the application of stress.
• What does deformation in rocks refer to?

  Changes in shape, size, and arrangement of rock materials in response to stress.
• What are the types of deformation in rocks?

  • Elastic Deformation: Returns to original shape after stress is removed.
  • Plastic Deformation: Permanent change without fracturing.
  • Brittle Deformation: Rocks break or fracture under stress.
  • Ductile Deformation: Rocks bend or flow without breaking.
• What is elastic deformation?

  Rocks return to their original shape once the stress is removed.
• What is plastic deformation?

  Rocks deform permanently without fracturing.
• What is brittle deformation?

  Rocks break or fracture in response to stress.
• What is ductile deformation?

  Rocks bend, flow, or fold without breaking.
• What are folds in geology?

  • Formed when rocks experience compressive stress.
  • Causes bending of rocks.
  • Can range from small-scale wrinkles to large mountain ranges.
  • Example: The Appalachian Mountains.
• What is a monocline?

  A single, large, step-like fold in the rock layers.
• How does a monocline form?

  It results from movement along a fault beneath the surface.
• What is an anticline?

  Upward-folding structures where the oldest rock layers are at the core.
• How does an anticline form?

  It results from compressive stress causing rocks to bend and arch upward.
• What is a syncline?

  Downward-folding structures where the youngest rock layers are at the core.
• How does a syncline form?

  It results from compressive stress, forming a trough-like structure.
• What are faults in geology?

  Faults are fractures or zones of fracture in rocks.
• What happens when rocks fracture along a fault?

  Blocks of rock can move around with one another.
• What type of stress causes normal faults?

  Tensional stress.
• What is a normal fault?

  Occurs when the hanging wall moves downward relative to the footwall.