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Download Ocean Trenches and Earthquakes: Plate Convergence and Magmatic Arcs and more Quizzes Oceanography in PDF only on Docsity!
Map
Representation of information about the surface of an object.
Can represent all types of data like temperature and depth
TERM 2
Spherical Coordinates
DEFINITION 2
Used to define a grid on the surface of the earth. Latitude
and logitude
TERM 3
Equator
DEFINITION 3
great circle around the earth that includes all points equally
distant from the poles
TERM 4
Parallels of Latitude
DEFINITION 4
small circles parallel to the equator. East-west circle marking
angels measured form the center of the Earth to points
above and below the equator.
TERM 5
Meridians of Longitude
DEFINITION 5
Great circles perpendicular to the equator. Measure angles
east-west of the prime meridian (0 longitude) set to intersect
city of Greenwich, England
Latitude and Longitude Combined
Make a grid that can be used to define the location of points
on the Earth's surface
TERM 7
Cross Sections
DEFINITION 7
Projects that are slices perpendicular to the surface of the
earth. Allow us to view profiles of the Earth's surface from
the side. Describe geological structures in the interior of
Earth and illustrating water properties across ocean basins.
TERM 8
Vertical Exaggeration
DEFINITION 8
Vertical scale stretched out relative to horizontal
scale.Horizontal scale divided by vertical scale
TERM 9
Extrapolation
DEFINITION 9
Predicting values outside the range of plotted points on a
graph
TERM 10
Interpolation
DEFINITION 10
Use line on graph to predict values between the plotted
points
Oceanic Ridge and Rise System
Where new lithospheric plates. Mountain features on the
seafloor where plates move apart. as sea floor spreads apart,
basaltic magma derived from partial melting of the
asthenosphere rises to the surface, solidifies, and becomes
new crust at the edge of the lithospheric plates. Associate
with "Rift Valleys"
TERM 17
Diverge
DEFINITION 17
Plates move apart
TERM 18
Basaltic Magma
DEFINITION 18
Comes from partial melting of the asthenosphere, rises to
surface, solidifies, and becomes new crust at the edge of the
lithospheric plates
TERM 19
Ocean ridge system has ___ heat flow, ___
volcanic activity, and ___ earth quakes
DEFINITION 19
HighHighHigh
TERM 20
Why are earthquakes shallow in the Oceanic
Ridge System?
DEFINITION 20
The rising asthenosphere and magma bring heat close to the
surface allowing rocks below the crust to flow instead of
breaking
Process of Subduction
Destroys new lithospheric material
TERM 22
Plates Converge
DEFINITION 22
one lithospheric plate forced down into the mantel beneath
the other plate. Visible on sea floor and deep ocean
trenches.
TERM 23
Plate convergence in deep sea ocean
trenches are characterized by ___
earthquakes
DEFINITION 23
shallow, intermediate, and deep focus
TERM 24
Why are deep-focus earthquakes possible in
deep ocean trenches?
DEFINITION 24
the cold brittle lithosphere is being pushed deep into the
mantle
TERM 25
Magmatic Arcs
DEFINITION 25
consequence of subductionchains of volcanoes that lie
parallel to trenches and above subducted slabs of
lithosphere
Transform Fault
two plates are moving in parallel but opposing directions
sliding past each otherobserved on seafloor as offsets in the
axis of ocean ridges
TERM 32
Transform faults are characterized by __
earthquakes
DEFINITION 32
shallow
TERM 33
Heat flow is __ at transform margins
DEFINITION 33
low
TERM 34
Young/Incipient Ocean Basins
DEFINITION 34
similar to mid-ocean ridges but more limited in extent.
Represent intermediate stages of continental rifting and
ocean-basin formation.Examples: Gult of California and the
Red Sea
TERM 35
Oceanic-Oceanic Plate Convergence
DEFINITION 35
Subduction of denser plate forming deep ocean trenches and
volcanic island arcsExamples: Aleutians, Puerto Rico-lesser
Antilles, and Tonga
Oceanic-Continental Plate Convergence
High density oceanic plate subducted under contenental
plate leading to the formation of an ocean trench adjacent to
the continent with a chain of volcanic mounts on the
continentExamples: Andes, Cascade Range, Peninsular
Ranges of Central America
TERM 37
Continental-Continental Plate Convergence
DEFINITION 37
Neither of the low density plates can be subducted into the
dense mantle. Intense compression of pre-existing
continental rocks create mountains along the
boundaryExamples: Zargros, Himalayas, and Alps
TERM 38
Mid-Atlantic Ridge is split down the middle by
___
DEFINITION 38
A central rift valley that isn't a continuous line of mountains.
Broken by offsets along linear zones of fracturing and extend
for long distances away from the ridge axis at right angels to
the central rift valley.
TERM 39
Fracture Zone
DEFINITION 39
Active faulting along ridges likely to occur in only a portion of
the zone lying between offset ridge segments. This is called
the transform fault.
TERM 40
Ridge Transformations
DEFINITION 40
faults oriented perpendicular ro the axes of mid-ocean
ridges, offsetting the ridge axes
Hotspots
Mantle plumes rising from deep mantle sources that produce
stationary source of volcanism for millions of years
accompanied by numerous shallow earthquakesExample:
Hawaiian Island cain and Emperor Seamount
TERM 47
Hotspot Formation
DEFINITION 47
form sa lithosphere passes over the stationary volcanic
source
TERM 48
What two major areas can the Earth be
divided into?
DEFINITION 48
Ocean basins and continents
TERM 49
Oceans cover __% of the
Earth?
DEFINITION 49
TERM 50
A large fraction of ocean is underlain by
relatively shallow
DEFINITION 50
Continental Margins
Average depth of the ocean is ___m
3700m
TERM 52
Continents have an average elevation of ___m
above sea level
DEFINITION 52
840m
TERM 53
Theory of Isostasy
DEFINITION 53
Suggests that Earth consists of blocks of rigid lithosphere
which are floating in isostatic equilibrium on a plastic region
of the Earth's mantel called the asthenosphere
TERM 54
Buoyancy
DEFINITION 54
Rigid body floating on a fluid will sink into the fluid until the
mass of the displaced fluid exactly equals the total mass of
the rigid body
TERM 55
____ is essential to understanding
isostasy
DEFINITION 55
Buoyancy
Thickness of continental crust
35km
TERM 62
Composition of continental crust and density
DEFINITION 62
granite2.8g/cm^
TERM 63
Thickness of oceanic crust
DEFINITION 63
5km
TERM 64
Composition of oceanic crust and density
DEFINITION 64
basalt3.0g?cm^
TERM 65
Due to ____ the continents stand at a higher
elevation because they are composed of ____
masses of ___ density materials
DEFINITION 65
isostasythicklow
Why do land mountain ranges stand high
compared to oceanic ones?
Land are composed of thick granite up to 70km thickOcean
mountains stand high because the lithosphere is hot and has
a lower density than the lithosphere of the deeper ocean
basins
TERM 67
Reminder of upper mantle material has
density of _____
DEFINITION 67
3.3 g?cm^
TERM 68
2 Types of Continental
Margins
DEFINITION 68
Atlantic and Pacific
TERM 69
Atlantic Continental
Margin
DEFINITION 69
wide gently sloping continental shelf, steep continental slope
descending to the deep sea and flatter continental rise at
base of the slope formed by accumulation of sedimentary
materials
TERM 70
Pacific Continental
Margin
DEFINITION 70
narrow shelf and slope descending into a deep marginal
trough/trench parallel to the continental marginExamples:
Area off Chile and Peru
Submarine Canyons
Steep walled V shaped valleys on the sea floor of the
continental slope and open out at a depth onto the
continental rise
TERM 77
Submarine canyons are most associated with
what geographical feature
DEFINITION 77
Mouths of large rivers
TERM 78
Why are submarine canyons
important
DEFINITION 78
serve as major unit which funnel turbidity currents and
sediments from the continental shelf onto the deep ocean
floor
TERM 79
Submarine fans
DEFINITION 79
large lobes of sediment associated with submarine canyons
TERM 80
Mid-Ocean Ridge and Rise System
DEFINITION 80
60,000km longHas central rift valley and rugged topography
on flanks. Stands 1-3 km above the deeper ocean basin
What normally cuts off the mid-ocean ridge
and rise system
Fracture Zones
TERM 82
Fracture Zones
DEFINITION 82
Linear zones of irregular topography on the sea floor 10-
100km wide and up to 3500km long.
TERM 83
What characterizes fracture
zones
DEFINITION 83
escarpments that can be from 100-4000m high and separate
regions of the seafloor of different depths
TERM 84
Abyssal Hills
DEFINITION 84
typically 5km deepgently rolling hills due to large sediment
coveringcommon in Pacific continental margins
TERM 85
Abyssal Plains
DEFINITION 85
common in Atlantic continental marginssediments from
turbidity currents have flowed off the continental rise and
spread over ocean floor producing extremely flat stretches of
ocean floor
4 common genetic
classifications
Terrigenous, Biogenous, Hydrogenous, Cosmogenous
TERM 92
Terrigenous sediments
DEFINITION 92
Derived from weathering of continents, volcanic activity, and
erosionfound near continental margins and deeper ocean
basins
TERM 93
Biogenous Sediments
DEFINITION 93
originate from secretion of skeletal materials by marine
organisms. mostly biologically produced inorganic matter like
skeletal remains
TERM 94
Hydrogenous
Sediment
DEFINITION 94
Inorganic sediments that originates by the precipitation of
minerals from seawater
TERM 95
Cosmogenous
Sediment
DEFINITION 95
From spaceimpact deposits or spherules that are sand-sized
due to burning in the upper atmosphere
Boulder
greater than 25cm
TERM 97
Cobble
DEFINITION 97
6.4-25cm
TERM 98
Pebble
DEFINITION 98
4mm-6.4cm
TERM 99
Granule
DEFINITION 99
2mm-4mm
TERM 100
Sand
DEFINITION 100
1/16mm - 2mm
