Term
| What is the definition of a desert? |
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Definition
| 1. An arid (dry), less than 250 ml. of rainfall per year |
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Term
| What 2 mechanisms of wind erosion did we discuss? How do they work? What features do they form? |
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Definition
a. Abrasion – wind blown particles against the surface of the rock
i. Arches, ventifacts,etc.
b. Deflation – removing small particles, leaving the big ones behind
i. Creates desert pavement |
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Term
| What 5 types of deserts did we discuss? How is each type classified? |
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Definition
2. Polar, subtropical, coastal, continental interior, rain-shadow
a. Can tell by the climate |
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Term
| What types of sand dunes did we discuss? What do they look like? What 3 factors influence dune formation? |
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Definition
a. barchan dunes – crescent shaped, migrate across the desert, wind blows from one direction
b. star dunes – star shaped, wind blows regularly in multiple directions, less sand, symmetrical
c. parabolic – u-shaped and concave, coastal deserts w/ vegetation
d. Transverse – like barchan, but are connected + are perpendicular to the wind
e. Longitudinal dunes – parallel to the wind, + have less sand, multidirectional winds
f. Wind, vegetation + sand supply – creates the difference between sand dunes |
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Term
| What desert features are formed by water? |
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Definition
a. Flash floods
b. Alluvial fans – sand deposit
c. bahata – many alluvial fans together
d. Large steep canyons |
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Term
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Definition
| a. Creation of desert conditions in non-desert areas (ex. dust bowl) |
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Term
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Definition
| a. Compaction + recrystallization of snow – forms glacial ice |
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Term
| Does glacial ice flow/move? Why/Why not? |
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Definition
a. Ice moves w/in the glacier
b. Gravity is the force that moves glacial ice |
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Term
| What types of glaciers did we discuss? What do they look like? |
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Definition
9. Types of glaciers
a. Circe – Bowl shaped, most valley glaciers start here
b. Valley – Surrounded by mountains – in the valley
c. Fjord – Parts of the glacier is replaced by water
d. Piedmont –
e. Ice cap – higher elevation, circular, cover the whole peak of mountain
f. Ice sheet – covers the entire continent |
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Term
| What are the terms for glacial gains and losses? What is the most important factor in a glacier’s mass balance? |
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Definition
10. Gain/losses
a. Accumulation - gain
b. Ablation - loss
c. Net gain/loss of ice = mass balance |
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Term
| What depositional features are associated with glaciers? What do they look like? |
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Definition
11. Depsitional features – rocks form glacial deposition called till
a. Morraines – Lateral, terminal, medial
i. Lateral on the side, terminal – end of the glacier, Medial – leave a ridge of till |
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Term
| What observations led Wegener to propose continental drift? |
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Definition
12. Wegener
a. Continental margins fit
b. Fossils matched
c. rock ages matched
d. single mountain chain
e. glacial land forms |
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Term
| What developments led to the theory of plate tectonics? |
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Definition
13. Seafloor spreading. Mid sea ridges were made of the youngest rocks. Older rocks symmetrically situated on either side. Could map pole reversals.
a. Paleomagnitism – could map pole reversals
b. GPS measurements |
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Term
| Describe the ages of rocks on either side of mid-ocean ridges. |
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Definition
14. Ages of rocks on either side
a. Rocks are older the further away they are from the ridges
b. The youngest rocks are in the middle of the ridge |
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Term
| What features are associated with plate boundaries? |
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Definition
15. Features of plate boundaries
a. rift valleys
b. mountains
c. mid ocean ridges
d. volcanoes |
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Term
| What are the differences between oceanic and continental crust? |
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Definition
16. Oceanic vs continental crust
a. Oceanic is younger, mafic, denser, thinner
b. Continetal is older, felsic, less dense, thicker
c. Oceanic crust is younger b/c that is where it is being created |
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Term
| What are the 3 types of plate boundaries? Where could you find an example of each? What types of earthquakes are associated with each? |
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Definition
17. 3 types of plate boundaries
a. Divergent – rift valleys + mid ocean ridges – tend to be fairly weak and shallow (brittle + weak rocks)
b. Convergent – island + volcanic sea mountains – Continental collision boundary (deep + very powerful earthquakes)
c. Transform – San Andreas fault – Shallow earthquakes (can be powerful and frequent) |
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Term
| What are the different kinds of convergent boundaries? |
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Definition
18. Convergent boundaries
a. Ocean to continent (ocean gets subducted b/c it is denser)
b. Ocean to ocean
c. Continent to continent |
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Term
| What is the difference between conduction and convection? |
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Definition
19. Conduction vs. convection
a. Convection – material is moving + recycling
b. Conduction – heat moves through a solid body w/out deforming it |
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Term
| What is unique about Hawaii’s volcanism (w/regard to plate boundaries)? |
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Definition
20. Hawaii’s volcanism
a. Hot spots track plate movement |
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Term
| What is the Elastic Rebound Theory? |
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Definition
21. Elastic rebound theory
a. Continuing stress along the fault |
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Term
| What secondary hazards are caused by EQs? |
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Definition
22. Secondary hazards
a. Tsunamis, fires, landslides, seche, other earthquakes |
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Term
| What are the differences between P and S waves? |
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Definition
23. P + S Waves
a. P waves are compressional like sound (travels through solids, liquids, gasses) are faster
b. S Waves are slower (only travel through solid) |
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Term
| How are EQ epicenters located? |
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Definition
24. EQ Epicenters located
a. Seismogram, interval + triangulation (need all 3) |
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Term
| What are some methods to predict earthquakes? |
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Definition
25. Methods to predict earthquakes
a. Looking for tectonic disturbances
b. Geologic record to see if there have been earthquakes in the past
i. Paleoseismology – looking at earthquake record
c. Accuracy – Short term is not accurate at all, long term is more accurate, but still isn’t that good |
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Term
| What is the basic structure of the Earth (what are the layers)? How do we know? |
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Definition
26. Basic structure of the earth
a. Crust, mantle, inner core, outer core
b. Seismic waves from different earthquakes, looking at how the waves behave as they move throughout the earth |
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Term
| How do we know the Earth has a liquid outer core? |
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Definition
27. Liquid outer core
a. S-waves cannot move through liquid, that’s how we know that there is a liquid inner core
b. S-waves not moving is known as a shadow zone
c. Other evidence – the earth has a magnetic field |
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Term
| What is a hanging wall? How can its movement be used to identify a type of fault? |
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Definition
28. hanging wall
a. Top arrangement of a fault – the hanging wall is the block on top of the fault |
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Term
| What kinds of stress lead to normal, reverse/thrust, and transform faults? |
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Definition
29. Hanging wall moves up = Reverse
a. Tensional stress – normal fault (hanging wall moves down)
b. Compressional stresses – thrust fault (hanging wall moves up)
c. Shear/parallel stress – Transform fault – (moves side to side) |
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Term
| What is the relationship between a magma’s viscosity, silica content, temperature, dissolved gas content, and explosiveness? |
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Definition
30. Relationship between
a. High viscosity = lower temperature, higher silica content, more gas content, more explosive
b. Low viscosity = opposite of above |
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Term
| What are the differences between shield volcanoes, cinder cones, and stratovolcanoes? (Shape, magma type, eruptions) |
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Definition
31. Volcano Types
a. Shield – gentle slope, low viscosity, non explosive
b. cinder cones – medium slope, medium viscosity, medium explosiveness
c. Stratovolcanoes – steep slope – high viscosity, big explosion |
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Term
| What type of eruption is most explosive? Least? |
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Definition
32. Eruption
a. Plinian - Biggest
b. Hawaiian |
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Term
| Does Mt. St. Helens have silica rich or silica poor lava? How about Hawaii? Does either represent a threat to humans? |
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Definition
33. mt. St. Helen’s – silica rich; Hawaii – silica poor
a. Mt. St. Helen’s = more explosive than Hawaiian Volcanoes |
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Term
| What are craters, calderas, and geysers? |
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Definition
34. Difference between caldera + crater
a. Crater – Initial explosion
b. Caldera – much larger than craters, from the collapse of the magma chamber |
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Term
| What are primary volcanic hazards? Secondary? |
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Definition
35. Primary hazards
a. Lava flow
b. Pyroclastic flow
c. Ashes
d. Debris |
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Term
| How do major eruptions affect climate? |
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Definition
36. Secondary Hazards
a. Fire
b. Earthquakes
c. lanslides
d. mudflows (lahars)
e. flooding
f. tsunamis |
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Term
| What are some beneficial effects of volcanic activity? |
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Definition
37. Benefit of volcanoes
a. Rich soil
b. geothermal heat
c. Brings a lot of |
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Term
| What activity can be observed to predict eruptions? |
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Definition
38. Prediction of volcanoes
a. increase release of gasses
b. bulging of nearby rock
c. more frequent earthquakes
d. increased temp of rock |
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Term
| Under what temperature, pressure, and moisture content do rocks most readily melt? |
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Definition
39. Temp
a. High temp = increase melt
b. Reducing pressure – easier to melt
c. Increase moisture content = easier to melt |
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Term
| What types of plutons did we discuss? What are the similarities/differences between them? |
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Definition
40. Plutons?
a. Stocks/Batholiths
b. Dikes/sills
c. Volcanic necks + Columnar basalt
d. Intrusive igneous activity – different from the surrounding rock |
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