Geological Oceanography (part 1) Flashcards
solar system was formed
5 bya
World ocean covers about _ of the planet’s surface
70.8%
The process of heating continued for several hundred
million years, until the temperature at the center of the earth was high enough to melt _ and _.
iron and nickel
Today _ of water covers the earth’s surface and forms the ocean, the LARGEST HABITAT ON THE PLANET.
1.37 cubic kilometers
is a continuous mass of water that covers most of
the planet
WORLD OCEAN,
True or False: Other divisions of the world ocean, such as seas and gulfs, are so named for our convenience and are in reality only temporary features of the single world ocean
True
body of salt water that is smaller than an
ocean and is more or less land locked.
sea
give examples of sea
Mediterranean Sea, Red Sea, and Caribbean Sea
smaller body of water that is mostly cut off from the larger ocean or sea by land formations.
gulf
give examples of gulf
Gulf of California, Gulf of Mexico, and Persian Gulf
The movement of the seafloor also causes movement of the continents that rest on it, a process known as
continental drift.
True or False: Inner core is liquid
False
solid
Same composition as the inner core,
but under less pressure and thus
cooler
outer core
consists of a transition
zone and a thick layer of liquid material
outer core
thickest layer and
contains the greatest mass of material.
mantle
The mantle is mainly composed of
magnesium–iron silicates
outermost layer of
the earth is the thinnest
and coolest of all
crust
THICKER and slightly less dense than the
oceanic crust and is mainly composed of granite, which contains
mostly lightweight silicate-rich minerals, such as quartz and
feldspar.
continental crust
Continental crust is THICKER and slightly less dense than the
oceanic crust and is mainly composed of _, which contains
mostly lightweight silicate-rich minerals, such as quartz and
feldspar.
granite
primarily composed of basalt-type rock,
which has a lower silicate content and is higher in iron and
magnesium than granite.
oceanic crust
The layer of the mantle just below the crust is also composed of
rigid, basalt-type rock that is fused to the crust. The region of crust
and upper mantle is called the _
lithosphere
Region of mantle below the crust is known as the _
asthenosphere
True or False: The asthenosphere is thought to be liquid, and it is able to flow under
stress.
True
proponent of the Continental Drift Theory
Alfred Wegener
Over time, a long mountain range called a _ will form along the crack produced by the erupting magma,
midocean ridge
magma that oozes out of these mountain ranges, or ridge
systems, will cool and form new crust, known as _
oceanic basaltic
crust
runs along the length of a portion of the mountain
crests
rift valley
areas of high volcanic activity.
rift valley
linear regions of unusually irregular
ocean bottom, may also occur, running perpendicular to the ridges
and rises and separating sections of the range.
steep-sided fracture zones
In regions called _, such as the deep recesses of
ocean trenches, old crust at the bottom of the trenches sinks and
eventually reaches the mantle, where it is liquefied and recycled
by convection currents into the earth’s core
subduction zones
Force that causes
continental drift.
seafloor spreading
causes movement of the
basaltic crust of the
seafloor, and because
the continents rest on
this crust, they also
move, much in the same
way that boxes move on
a conveyor belt.
seafloor spreading
true or false: The highest seafloor temperatures occur in the regions of the
ridges; temperatures decrease with distance from the ridge.
True
The crust was thinnest and the rock oldest near the ridges
False;
youngest
Continuous chain of submarine volcanic mountains that encircles the globe like
the seams on a baseball
mid-ocean ridge
Largest geological feature on Earth
mid-ocean ridge
At regular intervals the mid-ocean ridge is displaced to one side or the other by
cracks, or faults, in the Earth’s crust known as _.
transform faults
Occasionally the submarine mountains of the ridge rise so high that they break
the surface to form islands, such as _ and the _
Iceland and Azores
mid-ocean ridg in the Atlantic
Mid-atlantic Ridge
surveys of the seafloor also revealed the existence of a system of deep depressions in the seafloor called _
Trenches
seven major lithospheric plates
pacific
eurasian
african
australian
north american
south american
antarctic plates
True or False: each of the seven major lithospheric plates are composed of continental or oceanic crust or both
True
At the midocean ridges, where plate boundaries move apart as new lithosphere is formed, _ occur
divergent plate boundaries occur
_ occur at trenches, where plates move toward each other and old lithosphere is destroyed
convergent plate
plates move past each other at regions known as
faults
special kind of fault that is found in sections of the midocean ridge
transform fault
the motion of the plates along faults produces a sharp demarcation and often a nearly continuous line of cliffs with sharp vertical drops known as _
escarpments
regions where the lithosphere splits, separates, and moves apart as new crust is formed are called _
rift zones
mid ocean ridge and rise systems represent the _
major rift zones
right at the center of the ridge, the plates are pulling apart that leaves a great gap or depression known as
central rift valley
as the hot water seeps through cracks in the Earth’s crust, it dissolves a variety of minerals, mainly _
sulfides
chimney-like structures that progressively build up around a vent as the mineral solidify
black smokers
organisms depend on the _ of bacteria for their nutrients
chemosynthetic activity
