Geology Exam Review PDF

.Geology Exam Review 1.What are the three types of volcanoes? Cinder cones (smallest volcanoes: have slopes of 40 degrees) Composite Volcanoes (stratovolcanoes) Shield Volcanoes 2. Where do volcanoes form? Most occur convergent plate boundaries Hot spots Divergent pla...

.Geology Exam Review 1.What are the three types of volcanoes? Cinder cones (smallest volcanoes: have slopes of 40 degrees) Composite Volcanoes (stratovolcanoes) Shield Volcanoes 2. Where do volcanoes form? Most occur convergent plate boundaries Hot spots Divergent plate boundaries 3. Understand sills, dikes, plutons, batholiths. Sills-flat intrusions of igneous rocks that form between preexisting rock layers; they occur parallel to the bedding of other rocks;horizontal sills are the most common Dikes-vertical sheet of rock that is formed in a fracture of pre existing rock body  Plutons- Batholiths- 4. How are lavas characterized? Mafic (Basaltic) lava-low viscosity,high temperature Intermediate(Andesite) lava- have a high silica content, moves slowly Silic(Rhyolitic lava)-have the highest silica content, lowest temperature,and is the rarest if lava 5. What controls viscosity in lavas? Viscosity-resistance to flow Temperature:Hotter lava flows easier Magma composition Driving forces 6. What are Pahoehoe and aa? What are pillow lavas? Pahoehoe is ropy, wave lille lava Aa-sharp angular lava 7. Know the types of eruptive styles of volcanoes. (effusive, phreatomagmatic, Plinian, vulcanian, etc) Effusive eruptions:mostly lava flows of low-viscosity basaltic lava Explosive(pyroclastic) eruptions: produce clouds of ashland debris with lava:erupt because of the build up of gas pressure in the magma Phreatomagmatic magma: water introduced into the magma chamber and create steam 8. Be familiar with volcanic hazards (i.e. lahars, tsunami’s etc.). Which is the most hazardous? Yellowstone is the most dangerous active volcano in the United States Pyroclastic flow- mix of lava blocks, pumice ash, got glasses Lahars-most dangerous volcanic landslides 9. Know the size classification of volcanic debris (lapilli, ash, bombs, blocks, etc) Ash-fine glassy fragment:less than 2mm Lapilli- walnut sized material (2-64mm) Blocks- hardened or cooled lava( bigger than 65 mm) Bombs- ejected hot lava:(bigger than 65 mm) 10. Where do most earthquakes occur? In the pacific ocean- “ring of fire” 11.What are shallow, intermediate, and deep focus earthquakes? Shallow- 0-70 km in depth, they originate within 60 Km of the earth outer surface ad are the most common as they are close to the surface of the earth Intermediate- 70-300 km in depth, less common and but can be felt is they are strong Deep- 300-700 km depths commonly occur in Benioff zones near subduction slaps 12. What’s unique about deep focus earthquakes? commonly occur in Benioff zones near subduction slaps as they go deep into the mantle 13. What causes earthquakes?  Faulting Movement of magma Volcanic eruptions 14. What’s the Richterscale? How does it work? How is it different from the Moment of Magnitude scale? Ritchersclae works on a logarithmic scale to measure the magnitude of an earthquake, specifically the size of seismic waves; log of 10 Moment of magnitude scale- is based on the total energy release, replaced Richter Scale and is used for larger earthquakes How to calculate: Each number increases in intensity by factor of 10: 1-10 Each number increase the amount of energy release by a factor of 32 15. What are body waves? Surface waves? How does each type of wave work? Body Waves-travel through the interior of the earth 2 main types: P-waves: are the fastest seismic waves and travel through solids, liquids, and gasses(longitudinal compressional waves) S-waves: are slower than p waves and can only travel through solids and don't pass through the earth inner core(Transverse shear waves)  Surface wave-travel along the earth's surface, they are the slowest waves 2 kind of surface waves: Rayleigh waves: cause the ground to move up and down as the waves passes Love waves- causes the ground to move side to side 16. What's So special about S-waves? They cannot pass through liquids 17. Be able to recognize the arrival of P and S waves on a seismograph. P waves are the first to arrive because they are the fastest seismic wave, they have smaller amplitudes  S waves are larger or more intense and tend to be longer and have a larger amplitude 18. How do we determine where an earthquake occurred? Triangulation: comparing the arrival of time of P and S waves at three different seismometers, scientist can determine the earthquakes is from each station and calculate its location 19. What are the relative speeds of each type of wave? P wave: 5 to 8 km/s S wave: 2 to 5 km/s 20. What’s an epicenter? Focus? Focus- the place where mechanical failure that generates an earthquake occurs Epicenter- is the point on earth's surface directly above the focus of an earthquake 21. What waves cause the most damage in an earthquake? Surface waves cause the most damage in an earthquake 22. What does the damage done in an earthquake depend on? The damage is primary dependent of the distance from the epicenter The type of substrate 23. Be familiar with earthquake related hazards. (e.g.seiches, liquefaction, tsunamis, etc.) Displacement Seiches-large waves that move back and forth Landslides Liquefaction Tsunamis 24. What is going on to cause earthquakes at New Madrid? Reactivation of a Pre-Cambrian Cambrian failed continental rift 25. What is the history of the New Madrid zone? New Madrid earthquakes have released more energy than any known historic earthquakes in the United States 26. What is an orogeny? Is a mountain-building process that takes place at a convergent plate margin 27. How old is the majority of the Earth’s topography? Is the Cretacegous age or younger 28. What is deformation? Refers to the process by which rocks or the Earth's crust change shape or position in response to stress 29. What two main modes of deformation are there and how are they affected by confining pressure, temperature, and fluids? Brittle Deformation:the material breaks Ductile deformation: the material changes shape without breaking 30. Where do mountain belts form? Convergent plate boundaries due to their abduction and collision In response to continental drifting and continental transform faulting 31. How can you explain old mountain belts in the stable interiors of continents? Old mountain belts in the stable interiors of continents are often remnants of ancient tectonic processes and can be explained through several geological concepts. These mountain belts are typically part of regions known as cratons, which are the stable, ancient cores of continents. Over time, these mountain belts have been eroded and weathered, but they provide valuable insights into the Earth's tectonic history.: 32. What are the four ways a body can react to applied force? Translation- a rock body is displaced; like moving from one place to another Rotation- a rock body rotates around an axes  Dilation-a rock body undergoes a change in volume without changing shape Distortion-a rock body undergoes a change in shape without changing it’s volume 33. What is stress? What is strain? Stress: force applied per unit area 3 Types of Stress: Compressional stress Tensional stress Shear stress 34. Are mountain chains permanent? No mountains are not permanent as they are weathered away over time 35. What controls the mechanical behavior of a rock? Rheology, Strain rate, Temperature, fluids, and pressure 36. Understand the concept of isostasy and how it relates to mountains. Isostasy- is the state of gravitational equilibrium between earth's crust and mantle such that the crust “floats” at an elevation that depends on its thickness and density  helps explain how mountains are "supported" and how they change over time, especially in response to erosion, tectonic activity, and the redistribution of mass. 37. What are joints? How many types? Veins? How are joints and veins different from faults? Joints: fractures in a rock body that are caused by tensional stress; systematic joints or unsystematic(no pattern) Veins: joints that are filled in by minerals 38. What are the three main kinds of faults and the stresses related to each (i.e. compression, tension, etc)? 3 main Faults: 1. Normal Fault: Caused by extensional stress 2. Reverse Fault:Caused by compressional stress  3. Strike-slip/Transform Fault: 39. How might you recognize faults? Faults may repeat stratigraphic sequence Faults may OMIT stratigraphic sequence Faults may move a rock body from one place to another 40. Why do folded rocks occur? What is the difference between buckling and bending? Folds occur when rock layers are subjected to compressional stress Buckling: the application of compressional force parallel to layering Bending: the application of force across layering 41. What is a synonym? Syncline? Antiform? Anticline?  Synonym-refers to the different terms that are used to describe the same or very similar geological features Syncline:folds have the youngest rocks in the middle of the fold Synform: if a fold has the shape of syncline but the age relationship is unknown 42. What are the parts of a fold? 43. What is vergence? Direction of axial plane when it isn't vertical 44. What does it mean if a fold is overturned? Recumbent? Upright? 45. How are mountains like icebergs? Both are exposed to forces of balance,erosion, and long term change 46. What is isostasy? Isostasy- is the state of gravitational equilibrium between earth's crust and mantle such that the crust “floats” at an elevation that depends on its thickness and density 47. What is exhumation? 48. What is a monocline? 49. What is meant by the term accrete when used in mountain building? 50. What is a craton? What is a shield?