FINAL Flashcards
Which of the following is not found near deep ocean trenches?
a. spreading centers
b. island arcs
c. earthquakes
d. volcanos
e. subduction zones
a. spreading centers
Moving from an oceanic ridge to an oceanic trench, the age of the lithospheric rock
a. decreases in proportion to the distance
b. is unrelated to the distance from the ridge
c. remains the same
d. increases in proportion to the distance
e. randomly varies
d. increases in proportion to the distance
The Mid-Atlantic Ridge is an example of a
a. divergent plate boundary
b. transform fault boundary
c. convergent plate boundary (continental to continental)
d. convergent plate boundary (continental to oceanic)
e. convergent plate boundary (oceanic to oceanic)
a. divergent plate boundary
Transform boundaries are also known as conservative plate boundaries because
a. they do not create lithosphere
b. they do not destroy lithosphere
c. they produce mild earthquakes
d. both a and b
e. a, b, c
d. both a and b
True or False: Slow moving spreading zones tend to be more gentle sloped than fast moving spreading zones.
False; Fast moving spreading zones tend to be more gentle sloped than slow moving spreading zones.
True or False: shear faults, trenches and mid ocean ridges are all features found at plate boundaries
True
oceanic to oceanic
which crust subducts and why?
older crust subducts because it is denser due to sediment build up
oceanic to continental
which crust subducts and why?
oceanic subducts because it is denser
continental to continental
which crust subducts and why?
neither subducts due to similarities in density
geographical features formed by
oceanic to oceanic
volcanic island arcs, trenches
geographical features formed by
oceanic to continental
trenches, volcanic mountain ranges
geographical features formed by
continental to continental
mountain ranges
What is the longest mountain system on Earth?
Mid-Ocean Ridge
Large volcanos on the seafloor that are cone-shaped on top because they never reached sea level are called
a. hot spots
b. black smokers
c. seamounts
d. guyots
e. mantle plume
c. seamounts
Which of the following does not correlate with the other words
a. mid-ocean ridge
b. abyssal plains
c. submarine canyon
d. seamount
e. tabletop
c. submarine canyon
True or False: Deep linear scars on the deep-ocean floor caused by plate convergence are called __subamarine canyons___
False; Submarine Trenches
True or False: The environment of deep-sea vents is characterized by large extremes in __pressure__
False; temperature
Carbon Dioxide is produced by living organisms during the process of
a. respiration
b. photosynthesis
c. decomposition
a. respiration
Which is a unique property of water?a. low surface tension
b. ability to absorb and lose heat quickly
c. ability to dissolve many ionic substances
c. ability to dissolve many ionic substances
Absorption of excess atmospheric CO2 from the atmosphere causes the pH of the oceans to
a. decrease due to decrease in H+ ions
b. decrease due to increase in H+ ions
c. increase due to decrease in H+ ions
d. increase due to increase in H+ ions
b. decrease due to increase in H+ ions
viscosity of the ocean water increases
a. as temperature decreases
b. as salt content decreases
c. as temperature increases
d. as salt content increases
a. as temperature decreases
The relatively high boiling and freezing points of water are due to
a. size of water molecules
b. ability of water molecules to form hydrogen bonds
c. the low heat capacity of water
d. the neutral pH of water
e. the shape of water molecules
b. ability of water molecules to form hydrogen bonds
How does an increase in density affect the speed of sound in water?
a. increase it
b. decreases it
c. no effect
d. sound cannot travel in water
a. increase it
bathymetry
the measurement of the ocean depths and the charting of the shape or topography of the ocean floor.
what are the two main marine regions?
continental margins and deep ocean basins
which main marine regions contain the most biological activity?
continental margin, specifically the continental shelf
what are the two classifications for contiental margins?
active margins, passive margins
active margine characteristics
steep continental slopes, narrow continental shelves, little to absent rises, continental volcanic arc, coastal mountain ranges, volcanic islands arc trenches, high seismic activity
passive margin characteristics
gentle continental slopes, wide continental shelves, built-up rises (build-up of sediment), not much seismic activity
What type of margin is costal California?
active margin
on the continental margin, where are most submarine canyons located?
continental shelf
Two ways subarine canyons are formed
turbidity currents and river system
why are abyssal plains so flat
sediment evens out over time
what is the difference between a seamount and a guyot
a guyot has a flat top and used to be an underwater island while a seamount is just an underwater mountain
what is the deepest ocean trench
mariana trench
the deepest part of the mariana trench is called ______ at _______ ft.
Challenger Deep, 36,201 ft
what geological features are associated wth nearby ocean trenches
volcanic island arcs, continental volcanic arcs, seamount
what creates a rift valley
divergent plates
where are hydrothermal vents found
mid-ocean ridges
what forms the chimney like structures that are commonly found around the hydrothermal vents?
solidified minerals
are all the Hawaiian Islands the same age? Is there a pattern to their age?
The Hawaiian islands are different ages. The older the island the farther away from the Hawaiian hotspot
How are the hawaiian islands formed
the hawaiian islands were formed through the hawaiian hotspot. the hotspot originally forms a seamount which later turns into an island
density
mass of a given volume of substance
Do higher temperatures increase or decrease density?
decrease
Earth is ___% water and ____% land
70, 30
The largest deepest ocean
Pacific Ocean
Half the size of the largest ocean, relatively small
Atlantic Ocean
mostly in the Southern Hemisphere
Indian ocean
Permanent layer of sea ice, very small compared to the other oceans
Artic Ocean
Defined as a meeting of currents
Southern/Antarctic Ocean
What are major differences between a sea and a ocean?
- the sea is smaller and shallower than the ocean
- sea is composed of saltwater
- sea is somewhat enclosed by water
- sea is directly connected to world oceans
What is the tallest mountain on Earth from base to top? How many total feet?
Maunakea; 9,632 meters
Why do geological processes have an influence on marine habitats?
geological processes sculpt the shoreline, determine water depth, and create new islands and underwater mountains.
When the young Earth was molten, where did the densest material flow? Where did the lighter materials flow
The densest material flowed toward the center of the planet. Lighter materials flowed to the surface.
Inner core
center of the earth, solid, iron
Outer Core
center of the earth, outer layer of the core, liquid, iron and nickel
mantle
very hot, flows like a liquid, middle of the earth between the core and the crust
crust
outermost layer, thin, ridgid skin
Why do the continents float on the mantle?
Continents float on the mantle because continental crusts are composed of the same low density material
The oceanic crust is composed of
basalt
the continental crust is composed of
granite
Density of oceanic crust
3.0 g/cm^3
Density of continental crust
2.7 g/cm^3
Thickness of oceanic crust
5 km
Thickness of continental crust
20 to 50 km
Geological age of oceanic crust
young
Geological age of continental crust
old
color of oceanic crust
dark
color of continental crust
light
Main materials in Oceanic Crust
iron and magnesium
Main materials in Continental Crust
sodium, potassium, calcium, and aluminum
lithosphere
the rigid outer part of the earth, consisting of the crust and upper mantle.
the lithosphere is found in ___ major plates. These plates are mobile and move.
7
mid ocean ridges
- Mountain ranges of the
deep. Volcanic in origin, only rises above sea
level in a few places (Iceland).
faults
Displacement of a ridge to one side or the other. Earthquakes are common here.
trenches
narrow, steep sided, and
deep. Common in the Pacific basin
What are earthquakes
associated with?
Plate boundaries.
What are volcanoes associated with?
trenches
Age of Ocean Floor(seafloor rock) Core samples:
sediment by the ridge/rises are younger and thin. By the trenches, the sediment is older and thick.
The age of seafloor rock and the layer of sediment, both ___ (increase, decrease) the farther distance from the ridge
increase
Lava and magma are high in ______
magnetite
What is thought to be the cause of
the magnetic reversals?
Changes in the motion of material in the iron rich outer core of the Earth
How are the magnetic striped
formed?
These magnetic particles will align in a direction parallel to the existing magnetic field at the time since they are fluid and have movement. Then at a certain temperature(~580 °C) they become “frozen” in that particular position; not changing their
direction.
Basalt
the rock type of oceanic crust
has very high concentrations of magnetite.
Each time the earth reversed its magnetic field, it was recorded in the _____ (0ceanic, continental) crust.
oceanic
- Rifts –
– large cracks in the seafloor caused by
the separation of ocean crust. Occurs at midoceans ridges
What is sea-floor spreading?
Lateral movement of oceanic lithosphere. New seafloor is created here.
How does sea-floor spreading work?
Magma reaches the surface at a spreading center (rift valley, center of the ridge/rise), cools and solidifies to become new crust.
* Crust moves laterally as the lithosphere is carried on the low-density molten material of
the asthenosphere.
* Eventually this crust is recycled back into the mantle at a trench location.
Spreading center
ridges are also called
spreading centers.
What are the “plates” of plate tectonics composed of?
Lithosphere
What is the asthenosphere?
The “plastic”
layer of the mantle. Denser and has a fluid-like
behavior.
How does plate separation
occur?
Through convection cells
Convection Cells:
Currents of low-density
molten material (magma) in
the asthenosphere rising up
to the lithosphere, running
along underneath it, then
cooling and sinking back
down.
How fast do plates separate?
2 to 18 cm per year, depending on location.
Where is old lithosphere destroyed, or “recycled” back to the mantel?
At deep-ocean trenches
Why do earthquakes and volcanoes form at these
locations?
Large slabs of lithosphere are colliding, with one sinking
below another. This movement causes earthquakes and as the
sinking plate begins to melt in the much hotter mantle, the
molten material, which is less dense, rises to form volcanoes on
the Earth’s surface.
Slab Pull Theory
Plates separate at mid-ocean ridges. Magma rises at these ridges,
cools becoming denser. Eventually this cold, dense lithosphere sinks
back into the mantle, pulling the slab of lithosphere
continental margins
boundaries between continental and oceanic crust. Shallow and close to shore
continental shelf
portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea
Submarine Canyons
narrow steep sided valleys that cut into continental slopes and continental rises of the ocean.
Formed by turbidity currents
shelf break
steepening of the bottom that marks the seaward limit of the continental shelf which begins the continental slope.
continental slope
closest to the exact edge of the continent. Begins at shelf break and descends to deep sea-floor
continental rise
closest to the exact edge of the continent. Begins at shelf break and descends to deep sea floor.
deep ocean basin
deep water area, further from land
turbidity currents
a rapid downhill flow of water caused by increased density due to high amounts of sediment
underwater avalanche of sediment
mid ocean ridges
shallow waters close to the middle of deep ocean basins
Why is the Southern Hemisphere referred to as the water hemisphere?
80% of the Southern Hemisphere is ocean as compared to only 61% of the Northern Hemisphere is earth.
Abyssal plains
a flat region of ocean floor usually at base of continental rise; slope of less that 1 degree toward mid ocean ridge
abyssal hills
small submarine hills
seamounts
a submarine mountain
guyots
seamount with flat top used to be islands that sunk below the sea cause of island weight
central rift valley
center of ridge system divergent boundary with magma rising up through the oceanic crust
hydrothermal vents
result of seawater percolating down through fissures in the ocean crust in the vicinity of spreading centers or subduction zones the cold sea water is heated by magma and reemerges to form the vents
mantle plume
stationary channel of magma usually far from any plate boundary that rises towards the surface from deep within the mantle
Why are hotspots and mantel plumes considered an intraplate feature
they tend to be far from plate boundaries
Which of the Hawaiian Islands is the youngest and which is the oldest??
youngest is the Big Island
oldest is kauai
What do coral reefs need to survive?
- shallow clear water for sunlight
- warm water 68 F - 90 F
- a site for attachment since coral are sessile organisms
Stages of a coral reef in order
- fringing reef
- barrier reef
- atoll
Fringing coral reef
grows at base of islands
ex. Carribean
Barrier Reef
Island begins to sink as coral grows. The coral is seperated from the island by a wide channel
Ex. French Polynesia and Australia
Atoll
Completely surrounded by coral and island is completely submerged
Ex. Pacific and a few in Indian and Caribbean Oceans
Other less important factors for growing coral
PH, salinity, and a turbidity of 0
fathom
measure of depth, 6 feet
sonar
a type of electronic depth sounding equipment/ echo sounding. transmits sound waves to the very bottom of the ocean. From the speed of the sound waves and the time required for the energy pulse to reach the ocean floor and come back up they can calculate the depth.
satellites
they measure the ocean floor from space by bouncing microwaves off the ocean surface.
Why is the transparency of the ocean important to
living organisms?
*It heats sea water, warming the surface layers
* It provides energy required by
phytoplankton.
* It is used for navigation by animals near the
surface.
What do water molecules
do to light as it passes
through water?
Absorbs and scatters it.
Why is the ocean water
bluish-green?
Since blue and green
wavelength are absorbed the
least, they are the most
available to be reflected back.
What is attenuation?
A decrease in the intensity of light over distance. The higher the attenuation the murkier the waters
What causes attenuation?
Attenuation is due to absorption by pigments and scattering by molecules and particles
Where would water of high attenuation be?
Coastal waters. High particle suspension.
Where would water of low attenuation be
found?
Open ocean waters
Secchi Dish
- Simple tool used to
measure attenuation.
*White disk is lowered
into the water. When it
just disappears from
sight, depth is
measured.
Pressure
- Increases at a rate of about 10 x
the air pressure at sea level per
100 meters of depth. - Humans can safely dive to about
130 feet(40 m). - Modern submarines dive to only
about 1950 ft(600 meters.)
Pressure increases at a rate of about 10 x the air pressure at
sea level per 100 meters of depth. Why?
As ocean depth increases, so does
pressure. Rate of 1 atm per meter of
depth.
Why would gas bladders and lungs shrink or
collapse, as pressure increase in water?
*The high pressure.
- Sound travels faster in water than in air. Speed of sound in salt water
______ m/s.
1500
why is there is no sound travel in a vacuum tube or in outer space.
Sound needs molecules to travel through. In water, molecules
are much closer together than in air.
Which sound travels farther in water, high frequency sound or low
frequency sound?
Low frequencies (high frequencies are dissipated
too quickly because of the higher energy). Speed
increases with increased temperature, pressure and
salt content.
The distance that sound travels in the ocean varies
greatly, depending primarily upon …
temperature, pressure, and salinity
How does sound locate objects?
Sound is reflected back after striking an object. The time required for
the return of a sent sound signal can be measured.
What is the typical salinity of seawater?
3.5 %
Is it just sodium and chlorine that make up the salinity?
No; S, Mg, Ca, K also account for most of the salinity.
(Sodium and chlorine account for about 85 % of the
dissolved solutes.)
Sea ice formation
when seawater freezes, dissolved
ions cannot fit in the ice’s crystalline structure.
Unfrozen seawater is left behind that has a higher
salinity.
How does an increase in salinity influence water’s
density?
As salinity increase so does the density.
What is the main source of oxygen in
the oceans?
Phytoplankton
Where are more dissolved gases found, based on
latitude, and why?
More dissolved gases are found in the higher latitudes.
Gases dissolve better in cold water that in warm. As
temperature decreases so does the kinetic energy of the
gas molecules. Less gas expands and rises so less escapes
from the body of water.
Polar
unequal sharing of electrons between the atoms and the unsymmetrical shape of a molecule
specific heat
heat required to raise the temp of the unit mass of a given amount
Does water have a high or low specific heat capacity? Why?
Water has a high specific heat capacity because water absorbs a lot of heat before it begins to heat up
affect salinity has on boiling point & freezing point of seawater
AS salinity increases the boiling point rises and the freezing point lowers
marine effect
locations close to the ocean experience a mild change in day-to-night temperatures
continental effect
less influenced by the ocean and has greater range in day-to-night temperatures
swells
waves that have moved out of their area of origin. Have long wavelengths with regular patterns of crests and troughs. Large amounts of energy and lose it quickly.
three factors of wave height
wind speed, fetch, and wind duration
wave height (amplitude)
vertical distance from crest to trough
wavelength
horizontal distance between 2 consecutive crests
frequency
number of wave crests passing point A each second
wave period
time required for the wave to crest at point A to reach point B
spilling wave
results in gently sloping ocean bottom. Loses energy slowly
plunging wave
results in moderatly steep ocean bottoms
surging waves
results from the ocean bottom having an abrupt slope. Erergy is compressed into a short distance and waves break quickly
diurnal tides
1 high tide, 1 low tide each day. commonly found in inland seas and bays
semidiurnal tides
2 high tides, two low tides. Commonly found on the Atlantic Coast of the US, west coast of Africa
mixed tides
2 high tides, two low tides. (high high tides). Most common tides
minus tide
a low tide that falls below the mean average
flood tide
rising tide
ebb tide
falling tide
When do neap tides occur
1/4 of a full moon
when do spring tides occur
new and full moons
Coriolis effect
the apparent deflection of objects moving in a straight path relative to the earth’s surface
Why does the Earth have seasons
because the earth is tilted on its axis and spins
doldrums & horse latitudes both have
areas of rising or descending air so there are very little cross winds
How does water vapor affect air temperature?
Increased water vapor in the atmosphere amplifies the warming caused by other greenhouse gases
trade winds
the steady, mostly easterly flow of the near-surface winds over tropical oceans. At 30 N and 30 S
the westerlies
westerly winds predominate in middle latitudes. Blowing towards the sub polar pressure belts. At 30 to 60 N and S
the polar easterlies
blowing from north and east. Unlike westerlies and trade winds, they are not global wind belts
sea breeze (onshore breeze)
land warms up during day and cooler air from water moves towards the land
land breeze (offshore breeze)
water warms up during day and cooler air from land moves towards the water
gryre
circular motion current systems
How many major ocean gyres are there
5
How many currents does each of the subtropical gyres have
4
western intensification
when two currents one on the west and one on the east are across from each other usually the western current is bigger, stronger, and faster than the eastern current
western boundary current names for the N. Pacific, S. Pacific and N. Atlantic
Kuroshio, East Australia and Gulf Stream currents
eastern boundary currents names for the N. Pacific, S. Pacific and N. Atlantic
California, Peru, and Canary currents
upwelling
cool water brought to surface rich with microscopic organisms
downwelling
waters converge and sink transports oxygen rich waters into depths
