Geology Test 3

Front 1

continental shelf

Back 1

shallow submarine platform at the edge of a continent

Front 2

continental slope

Back 2

relatively steep slope that extends from the continental shelf to the continental rise

Front 3

continental rise

Back 3

less steep slope that extends from the base of the continental slope to the abyssal plain

Front 4

abyssal plain

Back 4

extremely flat regions beyond the base of the continental rise

Front 5

submarine canyon

Back 5

V-shaped valleys that run across C. shelves and down C. sloeps

Front 6

abyssal fan

Back 6

fan-shaped deposits found at the base of submarine canyons

Front 7

turbidity currents

Back 7

great masses of sediment-laden water pulled downhill by gravity... *likely to play major role in canyon erosion *generated by underwater earthquakes, landslides, surface storms, discharge from sediment-laden rivers

Front 8

Passive Continental Margins

Back 8

geologically quiet (i.e. no plate boundaries) *sediment deposted via turbidity currents and by CONTOUR CURRENTS (bottom current parallel to the slopes of the margin)

Front 9

Active Continental Margins

Back 9

geologically active b/c of plate boundaries leading to EQs, young mtn belts & volcanoes

Front 10

ocean trench

Back 10

narrow, deep trough parallel to the edge of a continent or an island arc... *deepest parts of the oceans *Upper Benioff zone *Low heat flow *negative gravity anomalies

Front 11

seamounts

Back 11

conical undersea mtns that rise 1000m or more above the sea floor; *most are extinct volcanoes (except near id-ocean ridge or hot spot) *chains of seamounts from aseismic ridges (no EQs)

Front 12

guyots

Back 12

flat-topped seamounts; *cut by wave action *reefs common around them

Front 13

reefs

Back 13

wave-resistant ridges of coral, algae, and other calcareous organisms (calcium carbonate anatomical structures)

Front 14

fringing reef

Back 14

flat, table-like reefs attached directly to shore

Front 15

barrier reefs

Back 15

parallel to the shore, but are separated by wide, deep lagoons

Front 16

atolls

Back 16

circular reefs that rim lagoons

Front 17

terrigenous sediments

Back 17

land-derived sediments that have found their way to the sea floor; comprise continental rise and abyssal plains

Front 18

pelagic sediments

Back 18

settle slowly through the ocean water, and are derived from fine-grained clay (delivered primarily by wind) and skeletons of microscopic organisms *nearly absent on mid-oceanic ridge crests

Front 19

plate tectonics

Back 19

theory that Earth's surface is composed of large, thick plates that move and change in size *Glossopteris, Lystrosaurus, and Cynognathus found all continents

Front 20

Laurasia

Back 20

northern supercontinent containing N. America and Eurasia

Front 21

Gondwanaland

Back 21

southern SC containing S. America Africa India, Antarctica and Australia

Front 22

Pangaea

Back 22

________ is not the starting point for the movements of continents

Front 23

paleoclimatology

Back 23

glacial evidence... glacial till, eratics, and striations *Use these patterns to locate ancient poles relative to location of continents*

Front 24

coral reefs

Back 24

warm water, near equator

Front 25

polar wander

Back 25

theory that the ancient pole positions have changed 1. continents remained motionless and poles moved 2. (CORRECT ONE) Poles remained motioneless, and continents moved-->**Continental drift

Front 26

continental drift

Back 26

caused by centrifugal forces of Earth's rotation and gravitational forces (Wegener)

Front 27

paleomagnetism

Back 27

use of mineral magneitc properties to determine direction and distance to the magnetic pole when rocks formed

Front 28

mid-oceanic ridge

Back 28

underwater mtn system; typically has a valley (rift) running along its spine; characteristic of what is known as *oceanic spreading center **mid-ocean ridges of the world are connected and form a single global MOR system that is part of every ocean

Front 29

seafloor spreading

Back 29

1. flat-topped mtns under sea (guyots) 2. young sediments on sea floor 3. marine fossils found on ocean

Front 30

Vine-Matthews Hypothesis

Back 30

observations of magnetic anomalies on the ocean floor...... 1. Anomalies are parallel to the MOR 2. + and - anomalies form a miror image on either isde of the ridge 3. pattern of anomalies in the ocean matches the pattern of magnetic reversals observed ont he continents 4. pattern of anomalies is the same for the two major ocean basins

Front 31

magnetic anomalies

Back 31

able to measure the rate of plate motion; able to predict the age of the sea floor correlate the age reversals (from continental lava) to distance from the ridge

Front 32

divergent boundaries

Back 32

*tension-creates rifting. creates new ocean basins. basaltic volcanism.

Front 33

e afr rift valley

Back 33

example of divergent boundary valley?

Front 34

ocean-ocean convergence

Back 34

subduction causes a Benioff zone; creates a deep and broad trench

Front 35

accretionary wedge

Back 35

formed from sediments that are accreted onto the non-subducting tectonic plate at a convergent plate boundary

Front 36

continent-continent

Back 36

oceanic crust is first subducted until ocean "closes"; neither plate wants to subduct; crust is greatly thickened -> creates large mtn belt and shallow focus earthquakes

Front 37

continental collision

Back 37

mtn belts, thrust faults, "detached" subducting plate

Front 38

suture zone

Back 38

plate boundary is formed; continent-continent

Front 39

ocean-continent convergence

Back 39

oceanic plate subducts below less dense continental crust; subduction of ocean plate -> magma; forms and creates magmatic arc of andesitic volcanoes; isostatic uplift of continental crust; thrust faulting pushes mtn-belt rocks over ocean

Front 40

more silicic from addition of continental material

Back 40

ocean-continent volcanoes are more ___?

Front 41

ridge push

Back 41

sliding of lithosphere away from ridge crest, along slope due to gravity

Front 42

slab pull

Back 42

subducting lithosphere

Front 43

mass wasting

Back 43

downhill movement of masses of bedrock, rock debris, or soil, driven by the pull of gravity

Front 44

landslides

Back 44

far more costly in U.S., in terms of both lives and $, than all other geologic and weather hazards combined

Front 45

mass wasting*

Back 45

most easily avoidable of all major geologic hazards

Front 46

flow, slide, fall

Back 46

types of movement in mass wasting?

Front 47

rate of movement, type of material, type of movement

Back 47

classifications of mass wasting?

Front 48

flow

Back 48

descending mass moves downhill as a viscous fluid

Front 49

slide

Back 49

descending mass remains relatively intact, and descends along well-defined surfaces

Front 50

translational slide

Back 50

movement along plane parallel to motion

Front 51

rotational slide

Back 51

movement along a curved surface

Front 52

rock fall

Back 52

fastest, simplest and most obvious form of mass wasting; pieces of rock or regolith falling from a steep slope or cliff; often dislodged through frost action; rock debris accumulating at the bottom of the slope often forms a talus slope or talus cone

Front 53

gravity

Back 53

the driving force for mass wasting includes two components -> normal force and shear force

Front 54

normal force

Back 54

perpendicular to slope, component that "holds" block in place

Front 55

shear force

Back 55

parallel to the slope, component "pulls" block downslope

Front 56

shear strength

Back 56

resistance to movement or deformation; controlled by composition of material and water

Front 57

steepness of slope

Back 57

steeper slope = larger shear force

Front 58

triggers

Back 58

wave action, heavy rainfall, construction activities, earthquakes

Front 59

creep, earthflow, debris flow, mudflow, solifluction

Back 59

types of flow

Front 60

creep

Back 60

very slow downslope mvmt of soil; major contributing factors --> water in soil, daily freeze-thaw cycles; can easily be costly to maintain homes, etc. on creeping ground as foundations, walls, pipes, and driveways crack & shift downslope over time

Front 61

freeze-thaw cycles

Back 61

moves particles downslope b/w periods of frozen and thawed ground; house foundations must be engineered to withstand FTC... footing extends below the frostline

Front 62

earthflow

Back 62

Earth moves downslope as a highly viscous fluid; generally drier than other types of flow

Front 63

debris flow

Back 63

coarse material (boulders, gravel) is dominant; can move relatively slowly or quickly

Front 64

debris avalanches

Back 64

move very rapidly and also include air

Front 65

mudflow

Back 65

flowing mixture of debris and water; fine-grained material (sand, silt, clay) dominates

Front 66

solifluction

Back 66

flow of water-saturated soil over impermeable material either -->bedrock or permafrost

Front 67

mud flow

Back 67

when water content increases (from earthflow) you get?

Front 68

debris flow

Back 68

when grain size increases (From earthflow) you get?

Front 69

creep

Back 69

when rate increases (from earthflow) you get?

Front 70

solifluction

Back 70

this one is associated with permafrost? (from earthflow)

Front 71

rock slide; debris slide

Back 71

two types of slide?

Front 72

rockslide

Back 72

rapid sliding of a mass of beedrock along an inclined plane; * may be triggered by water or undercutting at the base of the slope * if the bedrock breaks up and moves rapidly --> rock avalanche (which is actually a type of flow b/c of the turbulent of the mass)

Front 73

debris slide

Back 73

coherent mass of debris (i.e. unconsolidated material) moving along a plane

Front 74

rockfall

Back 74

block of bedrock breaks off and falls freely or bounces down a cliff *cliffs may be undercut by wave action (i.e. along coasts or rivers) * construction activities may also oversteepen slopes

Front 75

talus

Back 75

whn rock accumulates at the base of a cliff

Front 76

angle of repose

Back 76

steepest angle at which a pile of unconsolidated grains remains stable

Front 77

hydrologic cycle

Back 77

accounts for how water is actually moving

Front 78

streams

Back 78

body of running water, confined to a channel, that runs downhill under the influence of gravity

Front 79

channel

Back 79

a long narrow depression eroded by a stream into rock into sediment

Front 80

headwater

Back 80

upper part of stream near its source in the mountains

Front 81

mouth

Back 81

place where a stream enters sea; lake or larger stream

Front 82

drainage basins

Back 82

total area drained by a stream; composed of the stream and tributaries; bounded by DIVIDES

Front 83

continental; major drainage; minor drainage

Back 83

3 types of divides

Front 84

drainage patterns

Back 84

arrangement of a stream and its tributaries; reflects the geology of the region (including rock types and structure) of the region

Front 85

dendritic drainage

Back 85

resembles a tree; branches (tributaries) flow to the main stream; typical in areas w/ flat-lying sedimentary rocks

Front 86

radial drainage

Back 86

streams flow outward from a central point; like the spokes of a wheel; typical in areas w/ conical mtns

Front 87

rectangular drainage

Back 87

tributaries have 90 degree bends and meet main streams at right angles; typical in areas w/ regularly fractured rock

Front 88

parallel

Back 88

main streams w/ short tributaries meeting at right angles; typical in areas where rocks have been tilted and layers of resistant rock (i.e. sandstone) alternate w/ softer rock (shale)