Oceanography Chp 4 - 6
From where does most of the material on the continental shelf come?
Erosion from the adjacent continent
What is the origin of most abyssal plain sediments?
Erosion from the continent
Why does the ocean not boil or freeze solid in different regions of the world?
Heat is transported by oceanic and atmospheric circulation
What piece of equipment was able to facilitate two new fields of science with the data it generated?
Piston corers
What is not a general characteristic of an active margin?
A broad shelf
Of what is the structure of carbon dioxide an example?
A compound
What is the only substance to have a higher heat capacity than liquid water?
Ammonia
Often formation on land can shed light on ocean processes. Which is true of the White Cliffs of Dover in England?
An accumulation of diatomaceous earth rise above sea level from plate tectonics
What statement is true of biogenous and terrigenous sediments?
biogenous sediments comprise of a larger area that terrigenous sediments
If a sediment is white in color, it is likely to be
biological in origin
SOFAR
fixing
Submarine Canyons
form at the junction b/w shelf and slope
Which is an example of an authigenic sediment?
manganese nodules
Bathymetry
measurement of depths of water in ocean
SONAR
navigation
hydrogen bond
sharing of electrons BETWEEN water
covalent bond
sharing of electrons WITHIN water
disphotic
some light
continental slope
steep, between shelf and rise
compound
substance that contains 2 or more different elements in a fixed proportion
KT event
tektites meteor strike end of the dinosaurs
thermocline
temperature
Approximately how much of the world's estimated oil and gas reserves can be found within the sediments of the continental margins?
two-thirds
Guyot
"table mounts" flat topped eroded by waves. west central pacific.
continental rise
apron of accumulated sediment that covers the oceanic crust along passive margins
How long is it estimated to take the oceans volume of water to circulate through the oceanic crust at spreading centers?
10 million years
What is the typical depth of light penetration in the open ocean?
100 meters
adhesion
2 different substances - stick to other materials
cohesion
2 similar substances - stick together
maximum density in water
4 degrees C - below it expands
Why is sensible heat detectable while heat that is not sensible cannot be measured?
A thermometer measures the decrease in temperature, but as a liquid changes to solid, the loss of heat is not measurable
To what is a Pacific type margin referring?
Active margin
What type of margin is generally steep?
Active margin
What contributes to the high biological activity and surface nutrients in southern polar waters?
All are contributing factors
What is characteristic of the water that is expelled from hydrothermal vents?
All of these choices are true.
What is true of bathymetry?
All of these choices are true.
What can cause hydrogenous calcium carbonate deposits? All of these choices: A decrease in the acidity of seawater A increase in seawater temperature Evaporation
All of these choices: A decrease in the acidity of seawater A increase in seawater temperature Evaporation
What statement describes turbidities?
All of these choices: They are propelled into position by gravity rather than water currents They are graded layers of terrigenous sand mixed with finer pelagic sediments They are composed of distinct layers
Where are abyssal plains most common?
Atlantic Ocean
The west coast of South America is known for its seasonal up welling. What kind of sediment is likely to be abundant based on this information?
Biogenous
How is sound transmitted through a medium?
By rapid pressure changes in a medium
What is considered an important factor in shaping western boundary continental rise?
Deep-ocean currents
What specifically connects the continental shelves to the deep ocean floor?
Continental slope
What process explains how hydrothermal vents are created?
Convection
___ connects atoms by sharing the energy of paired electrons
Covalent bonds.
passive margins
DIVERGING plates. ATLANTIC type. Spreading centers/MOR.
A deep ooze was discovered near Antarctica. What type is it likely to be?
Diatom ooze
What organism forms the White Cliffs of Dover?
Foraminifers (protzoa) Calcarious
What type of bathymetric feature was heavily influenced by wave action at some point in its history?
Guyot
What is one reason diatomaceous earth is economically valued? It can be broken up for gravel and used as building material
It can be broken up for gravel and used as building material
What is true of heat capacity?
It is the measure of heat required to raise the temperature of one gram by 1 degree Celsius
Which sediment is categorized under cosmogenous sediments?
Microtrktites
Which water mass is characterized by increasing density with deeper depths?
Pycnocline zone
What organism is likely to be found in siliceous ooze? Radiolarian
Radiolarian
What visible light wave is almost completely absorbed and converted to heat within the first few meters of the ocean?
Red light waves
Why is the sofar layer efficient for sound travel?
Refraction causes the sound energy to remain within the layer
What is the main source of terrigenous sediments?
Rivers
What is the main reason for the stratification in the north polar waters?
Salinity
What allows water to be a polar molecule?
Shape of the molecule
What is often found in the middle of manganese nodules?
Shark teeth or bone fragments
Which is not true of the relationship between latitude and ocean characteristics?
Temperate waters have the largest variation in salinity
Why does sound travel rapidly through the lower well mixed surface layer?
Temperature and salinity are homogenous
With what kind of sediments are igneous rocks associated?
Terrigenous
What is the calcium carbonate compensation depth?
The depth at which calcium carbonate starts to dissolve
Why does the latent heat of vaporization require so much heat energy?
The energy is used to break the hydrogen bonds
What was not a factor in making the mapping of the Earth's ocean more difficult?
The gravitational pull of underwater features
As pure water approaches its freezing point, the density decreases. Why does this happen?
The hydrogen bonds become rigid, allowing it to expand slightly.
What partly explains the seabed topography we observe?
The jostling due to plate tectonics
With what is the flatness of abyssal plains associated?
The large amounts of sediment.
Why does eastern North America continue to contain sediment from the last ice age?
The large rivers tend to end up in estuaries
Which is not a major factor in the width of a continental shelf?
The number of rivers depositing new sediments
What is thermal inertia?
The propensity for a substance to resist temperature changes.
What characterizes deep ocean sediments?
The sediments are well-sorted due to low energy fluctuations
What effect does temperature and pressure have on the speed of sounds when entering seawater?
The speed of sound decreases as temperature and pressure decrease
What is the name for a zone that decrease in temperature with depth?
Thermocline
What offsets the mid-Atlantic ridge's movement at fairly regular intervals?
Transform faults
___ are likely to be found in subduction zones.
Trenches.
What is thought to have an effect on the formation of submarine canyons?
Turbidity currents
What transports most of the sediments that forms the continental rise?
Turbidity currents
Which does not have an effect on water's density?
Viscosity
What is a shadow zone?
Zone where the divergence of sound waves creates a region that has little sound energy penetration
The submerged outer edge of a continent is called:
a continental margin
A continental margin facing a spreading ridge is considered ____ and ____.
a passive margin; diverging
capillarity
ability of water to move upward
shelf break
abrupt transition from shelf to slope
decrease salinity
add water
What is the difference between adhesion and cohesion?
adhesion is the tendency of water molecules to stick to solids while cohesion is the property that allows water molecules to stick to each other
euphotic
enough light for photosynthesis
There is an abundance of foraminifera shells found in sediment, it would be characterized as
calcareous ooze
Turbidity Currents
carve the submarine canyons - "avalanche" of sediments
Lithogenous/Terrigenous
comes from land. quartz and clays. dominant on continental margins, abyssal plains
active margins
continental margins near edge of CONVERGING plates. PACIFIC type. Trenches. earthquake and volcanic activity
Neritic sediments
continental shelf sediments "off the coast" primarily terrigenous
high latitudes
cool temps limited evaporation low salinity
low latitudes
evaporation high precipitin low high salinity
The ___ has a low ratio of volume in comparison to its area in the ocean.
deep ocean floor
pyctocline
density
Seamounts
do not rise above surface water. more than 1000 m in height. hotspots.
Cosmogenous
dust from space; meteorite debris tektite spheres
molecule
group of atoms held together by chemical bond
The pycnoclince isolates the majority of the world ocean from:
heating and cooling brought on by solar energy fluctuations
atom
identical particles that make up an element and cannot be broken down
aphotic
no light
Biogenous
organic; accumulation of hard parts of some marine animals. calcareous ooze (calcium-carbonate) siliceous ooze (silicon) plant-algae; animal- protozoan can form oil and natural gas
The sediments that occur on the slope, rise and deep ocean floor and orignate in the ocean are called
pelagic sediments
Hydrogenous
precipitation of dissolved mineral from water; often bacteria manganese nodules chemistry related (must have biogenous and lithogenous)
What is an example of terrigenous sediments?
quartz
clines
rapid change
increase salinity
remove water
halocline
salinity
Pelagic sediments
sediments of the slope, rise and deep ocean floor "of the sea" primarily biogenous
continental shelf
shallow,nearly flat, close to shore
In addition to information gained from stratigraphy, what contributed to the emergence of paleoceanography?
the advent of deep sea drilling
Satellites use ____ to calculate the depths of the ocean.
variations in elevation of surface water
What is not considered a disruption to the normal sorting of the neritic sediments?
wave action
If oceanic ridges in the Pacific are more active, then it is expected that the ridges are:
wide