GEOG1113L exam 2

plate tectonics

the starting point for understanding the distribution and formation of many collections of landforms around the world

volcanoes

the triangles represents what?

Deep earthquake

D represents what?

intermediate focus

I represents what?

shallow earthquake

S represents what?

slump

a rotational slide that involves movement along a curved slide plane?

alluvial fan

flashflood quickly moves down a dry canyon picking up loose weathered material, eventually depositing the mud and rock at the mouth of the canyon in what??

thrust (overthrust) fault

compression fault, but the upthrown block overrides the downthrown block at a low angle

reverse fault

compressional stresses produce the fault displacement

steep, V-shaped valley floors

describe the width & shape of the valley floors of the first-order streams in the Eds Creek drainage basin?

relatively small, very steep cone

details of a cinder cone:

tall, steep-sided symmetrical cone

details of a composite volcano:

very wide, gentle slopes

details of a shield volcano:

very irregular summit area

details of plug dome:

oxbow lake formed by cutoff meander

explain the formation of a narrow, triangle-shaped lake?

contour lines crossing the river make Vs pointing uphill

how can you tell which direction the river is flowing?

present course is steeper

how is the gradient of the present course different from the gradient of the boundary course?

first-order streams are in sharper v-shaped valleys; Eds Creek has slightly wider valley floor

how is the valley floor of Eds Creek different from the valley floors of the first-order streams?

the edge of the mesa should migrate to the north as it erodes back

if gradient were the only factor controlling the erosive power of these streams, what should happen to the position of the mesa edge with time?

mudflow

is a very wet mixture of water and rock that amasses in a stream valley then flows down with consistency of wet concrete

debris flows

mudflows that contain large boulders?

strike-slip fault

primarily horizontal and is produced by shear stresses

normal fault

result of extension-stresses working to stretch or pull apart the landscape

midocean ridge

the age pattern of volcanic ocean floor rocks suggest the location where new ocean floor is being created at a what?

age of volcanic ocean floor rock

the circle with number inside them represent what?

continent or island

the circles with dots inside them represent what?

drainage divide

the dashed line represent what that delimits the drainage basin of the middle stream from the drainage basins of the streams on either side?

subduction produces a pattern of deeper earthquakes as one plate plunges below the other

the pattern of earthquakes does what?

the drainage divide

the unimproved dirt road (the double-gray & white line) along "Ed's Ridge" roughly follows which natural feature associated with the Eds Creek drainage?

use the contour lines from each point & subtract

to find the elevation drop, you do what?

subduction, spreading centers, and hotspots

volcanic activity may be associated with what?

transform boundaries

what boundary do plates slide past each other?

divergent (midoceanic ridge)

what boundary indicates most likely a location of a midocean ridge?

convergent (oceanic-continental)

what boundary is most likely a location of a major volcanic mountain range similar to the Andes in south america?

convergent (oceanic-oceanic)

what boundary is most likely a location of a volcanic island arc?

divergent boundaries

what boundary is the spreading of a continent?

oceanic trenches

what can be found near the convergent plate boundaries?

creep or soil creep

what entails very slow downslope movement of the surface layer of hillside, often as the result of repeated freeze-thaw cycles of the soil layer?

shallow- to deep- focus earthquakes; volcanic islands

what evidence indicates a convergent (oceanic-oceanic) boundary?

shallow- too deep- focus earthquakes; volcanoes

what evidence is shown that indicates it is a convergent boundary?

age of ocean floor increases away from band of shallow earthquakes

what evidence shown on a map indicates it is a divergent boundary?

meanders cutting into the walls of the valley floor

what evidence suggests that the river is widening its valley through lateral erosion?

gradient decreases

what generally happens to the gradients of streams as the stream order increases??

landslide

what involves the movement of masses of rock - sliding downslope as a unit along a largely flat sliding plane?

became a runout slide that moved a great distance from its origin point

what is the OSO landslide?

earthflow

what leaves a scar at its starting point- in this case very wet material is flowing

rockfall

what mass wasting consist of loose, weathered rock falls to the foot of a cliff or steep slope?

small oxbow lake between; sandy dry channel between

what natural features suggest that a channel of a river once followed a course between the boundary course and the present course?

volcanoes associated with hotspots

where you see volcanic islands is where you can find what?

it reached high ground extending onto the valley floor from the opposite side

why did the debris separate into two lobes at the far end of the slide?

shorter distance; straighter course

why would a river be an advantage to river traffic such as barges?

bc it is a shield volcano; they are built from fluid lava flows

why would a volcano be known as the gentlest slope?

bc it is cinder-cone; they are built entirely of loose pyroclastics

why would a volcano be known as the steepest?

perhaps the rate of plate motion has changed over the last few million years; perhaps the location of the hotspot has drifted slightly

why would the your answers be different when calculating the age of volcanic rock?