Deforming the Earth s ection 4

1. Deforming 
the Earth section 4

2. Deformation the process by which the change of rock  is caused by stress  ex. spaghetti  can bend or break  same happens to rock layers  bend with stress  break when they reach their elastic  limit

3. Compression and tension stress that occurs when plates are 
 squeezed, collide is compression  compression at convergent boundaries  makes large mountain ranges  stress that occurs when an object is
  stretched = tension  tension = divergent boundaries  ex. mid ocean ridges

4. Folding Bending of rock layers because of stress in  the Earth's crust = folding since layers start out straight, folding is a  deformation

5. Types of folds Depending on how the rock layers 
deform, different types of folds are 
made anticlines - upward arching folds synclines- downward, troughs monoclines - folded at both ends  vertical stress Folds can be large or small  measured in kilometers or centimeters

6. Deformation Stress amount of force per unit area on any  given material  applies to the crust  different things can happen when a rock  is put under stress

10. Faulting Some rock layers break when stress is  applied surface which rocks break and slide  is a fault  blocks on either side of the fault are  called fault blocks

11. When faults are not vertical, understanding the side is important hanging wall foot wall two main types of faults can occur depending on the footwall and hanging wall

13. Reverse Fault -Hanging wall is rising -compression convergent boundary

14. Strike-Slip Fault

17. Plate Tectonics and Mountain Building Mountains exist because tectonic plates are  continually moving around and colliding with  one another When tectonic plates under go  compression or tension, they can form  mountains in several ways  folded mountains  faulted- block mountains  volcanic mountains

18. Folded Mountains  Highest mountain ranges in the world are  made up of folded mountains  form at convergent boundaries  form when rock layers are squeezed and  pushed upward  example Appalachian Mountain  formed 390 million years ago  when Africa collided with the North  American plate  other examples- Alps, Ural Mountains  and Himalayas

21. Fault- Block Mountains When tectonic forces put enough tensions  on the Earth's crust, a large number of  normal faults can result  Fault-block mountains form when tension  cause large blocks of crust to drop down  relative to the other blocks  sedimentary rock layers are tilted  upward by faulting and can produce   sharp, jagged peaks  ex. The Tetons

25. Volcanic Mountains Most of the world's volcanic mountains are  located at convergent boundaries where  oceanic crust sinks into the asthenosphere  at subduction zones  rock melts to form magma  magma rises to surface and erupts  to form volcanic mountains

26. Volcanic mountains can form under the sea  Sometimes these mountains can rise above  the surface to become islands Majority of tectonically active volcanic mountains  have formed around the Pacific plate  known as the Ring of Fire

30. Uplift and Subsidence Vertical movement of the crust is divided  into 2 types uplift- rising crust to higher elevations  subsidence - sinking of regions to lower  elevations

31. Uplifting of Depressed Rocks Mountains are a type of uplift  large areas rise without deforming  rebound  slowly springs back to previous  elevation  happens when weight is removed  from crust

32. Subsidence of Cooler Rocks hot rocks take up more space than cooler  rocks  like mid ocean ridges  farther from the ridge, rock is cooler and  denser  the ocean floor subsides

33. Tectonic Letdown subsidence can also happen when the 
lithosphere becomes stretched in rift zones