World Oceans Test 2
Grab sampler
Hinged device that obtains a sample from a specific location on the sea floor
________ sediments are produced in the water through chemical reactions
Hydrogenous
Diatomaceous ooze
Found at cold and temperate latitudes
Radiolarian ooze
Found beneath warm waters of equatorial latitudes
Coccolithophorids
Very small, covered with calcareous plates; phytoplankton
Sediment smaller than 0.0625 mm in diameter cannot be seen unaided and is called
mud
Active margin similar to
trench
What seafloor feature listed here would have a relatively low gravitational attraction resulting in a lower sea surface elevation above it?
trench
Of the organisms listed that create calcareous tests, which is the smallest overall?
Coccolithophores
Montmorillonite
Comes from volcanic materials
Guyots
Flat-topped, underwater features found at least 1000 m below the surface
Corer
Long barrel that obtains continuous and undisturbed sediment layer
Kaolinite
More abundant in the tropics than in polar regions
Illite
More common in the Northern Hemisphere
______ sediments are generally small particles that hit the ocean after surviving the trip from space through Earth's atmosphere.
cosmogenous
The particle size of terrigenous sediments generally ________ with distance from shore
decreases
Seabed resource exploitation ______
extends back to the time of ancient Greek civilization
Oil and gas are formed ______
from marine plants and animals
grains larger than 2 mm are called
gravel
Lithogenous particles are transported to the ocean by means of ______
gravity wind ice water
Abyssal plain similar to
guyout
High elevation features on the ocean floor draw water toward them because they have more mass, resulting in a relatively ______ elevation of the sea surface above them. On the other hand, depressions on the ocean floor have ______ mass and gravitational attraction, resulting in depressions on the sea surface above them.
high; less
The thickness of pelagic sediments ______ with increasing distance from mid-ocean ridges.
increases
Abyssal clay is often called red clay because these pelagic sediments are rich in the element
iron
The east coast of South America ______.
is a passive continental margin and has a relatively wide continental shelf
Deep-sea clays are composed of four minerals: chlorite, illite, kaolinite, and montmorillonite. Their distribution in the ocean reflects the ______ and geology of their source area and their transportation path before they are deposited. (Choose all that apply.)
latitude and climate
What is the name of the process through which loose sediments on the sea floor are transformed into sedimentary rock?
lithification
The ______ is the depth in the ocean at which calcareous skeletal material first begins to dissolve
lysocline
hydrogenous
manganese nodules
If sedimentary rock is subjected to increased temperature, pressure, and chemistry, _____________ rock, such as slate, results.
metamorphic
Gas hydrates are rich in _____
methane
The thickness, composition, distribution, and source of ______ provide oceanographers with valuable information on how Earth functions over long time scales.
ocean sediments
Of all seabed resources extracted from the sea floor or below, ______ represent more than 95% of the value
oil and gas
Depending on the chemical composition of the tests within them, pelagic sediments with over 30% biogenous materials are known as either calcareous or siliceous ______
ooze
Oil and gas are formed as marine plants and animals are slowly converted to concentrated hydrogen and carbon molecules in the absence of _____
oxygen
The study of ocean basin history through the analysis of sediments is called ______
paleoceanography
Earthquakes and sediment overloading on steep continental slopes can cause ______, which are fast-moving underwater flows of sediment and water
turbidity currents
A continental shelf is ______ than the water is deep
wider
What transportation agent is responsible for directly bringing large amounts of ash, sand, and clay particles up to 1000 km offshore?
wind
Radiolarians
zooplankton
Put the following sediments in the correct order according to size, with the largest particle type on the top and the smallest on the bottom
1. boulder 2. pebble 3. sand 4. silt 5. clay
Starting at the beach and moving seaward, put these features in the correct order in which you would encounter them
1. continental shelf 2. continental shelf break 3. continental slope 4. continental rise
Atoll
Coral found independent of land in a ring shape
Barrier reef
Coral found surrounding a seamount but separated from the land by a lagoon
Fringing reef
Coral growing adjacent to an exposed seamount
The standardized length of a fathom is _____ feet
6
What percent of marine sediment is terrigenous?
75%
Rivers such as the Ganges and Yellow carry a tremendous amount of sediment to the continental shelf every year. Annual neritic sedimentation rates such as this can be a high as _______.
8 meters
__________ sediments are derived from organisms
Biogenous
Manganese nodules on the sea floor are a possible resource of many desirable metal resources. Where are these nodules found?
Scattered in many different types of locations, including across the world's deep ocean floor
Currently, the majority of terrigenous sediments are accumulating in ______ and estuaries, which both act as sediment traps that keep this land-derived material from reaching the ocean.
deltas
biogenous
diatom and radiolarian oozes
The east coast of the United States is a(n) ______ continental margin.
passive
______margins have little, if any, tectonic activity
passive
______ sediments are those that are fine-grained and collect slowly on the deep-sea floor
pelagic
________ is a seabed resource used to produce fertilizers
phosphorite
Diatoms
phytoplankton
The deep-sea floor receives a ______ supply of sediment
constant but slow
In which location are most neritic sediments found?
continental shelf (top)
Which of the following describe continental slopes?
-Can link the continental shelf with the deep-ocean floor -Are steep -Might have submarine canyons
What physical processes are involved in the process of lithification (i.e., turning sediment into rock)?
-Cementation -Burial -Compaction
Which of the following sources provide significant amounts of airborne sediment to the sea?
-Deserts -Sand dunes -Volcanic ash
Which of the following conditions are necessary for the formation of an atoll?
-Either ocean levels rise or the volcanic island subsides. -Coral initially grows around a volcanic island in a fringing reef
Which of the following describe where coarse-grained sediments tend to be found on the sea floor?
-In high-energy environments -Close to their source areas -Close to shore
Various sedimentary rocks are formed on the sea floor, and they record important details about their environments, such as water depth, current directions, and biological environments. Choose the sedimentary rocks from the list below.
-Shale -Sandstone -Limestone
Which of the following describe trenches?
-Some of them are associated with island arc systems. -They are the deepest places in the oceans.
Which of the following are ways in which hydrogenous sediments form?
-Sulfides form as hot, mineral-rich water from vents cools very quickly. -Carbonates form by direct precipitation.
Which of the following describe neritic sediments?
-Transported by rivers to the ocean -Found near continental margins -Originate from rocks on land
Which of the following are sources of lithogenous particles in the ocean?
-Windblown dust -Ash from volcanic islands -Rocks transported by icebergs
Rank the environments by the sedimentation rates, with the highest at the top
1. Large river estuaries 2. quiet bays 3. continental shelf
Arrange the following sediment sizes in order from largest (on the top) to smallest (on the bottom)
1. boulder 2. cobble 3. pebble 4. granule 5. sand 6. silt 7. clay
Dredge
A net or basket dragged across the sea floor
Which of the following two sediment descriptions (one size and one shape) would be those that would settle the quickest?
A rounded particle A sand particle
Foraminifera
Amoeba-like animals, up to 1 mm in size
Oil and gas represent only 50% of the mineral value presently taken from the seafloor
FALSE
South America has both an active continental margin and a passive continental margin. These margins can be characterized by the width of their continental shelf. Where is the passive continental margin located?
On the east coast (Atlantic coast)
What are relict sediments?
Sediments deposited on continental shelves when they were not underwater (but now are
Pteropods
Snails, up to 1 cm in size
What are gas hydrates?
Solid, icelike structures composed primarily of methane
Seamounts
Steep-sided volcanoes on the ocean floor that may breach the surface
Abyssal plains
The flat, deep portions of the ocean floor
Which of the following devices would be best used to obtain a continuous and lengthy, undisturbed sediment sample from the sea floor?
corer
What happens to the majority of terrigenous sediments deposited on the continental margins?
They are moved seaward and down continental slopes by waves, currents, and turbidity flows
Abyssal hills
Very common features, less than 1000 m high
In what type of water does dissolution of siliceous tests most readily occur?
Warm, shallow water
Which of the following statements correctly describes the relationship between glacial ages, sea level, and continental shelves?
When glacial ages occur, water is tied up in glaciers, causing sea level to fall and more of the continental shelf to be exposed
Chlorite
common in high latitudes
_________ profiling uses the behavior of sound reflected at the sea floor to study the different layers of ocean sediments
acoustic
______margins commonly are marked by volcanoes and earthquakes
active
An ________ is formed as coral continues to grow upward while the volcanic island it has grown around slowly subsides until the land is under the ocean surface
atoll
Physical weathering of the ocean floor occurs primarily ______, whereas dissolution of minerals dominates chemical weathering
by waves and currents
The ______ is the depth at which the amount of calcareous material preserved falls below 20% of the total sediment.
carbonate compensation depth (CCD)
Abyssal ______ is pelagic lithogenous sediment that accumulates very slowly on the deep-sea floor
clay
Let us start with a turbidity current that carries a poorly sorted sediment down the continental slope and into the deep ocean. Which sized sediment particles likely will be transported the farthest from their origin?
clay
Manganese nodule mining is being considered because of their high content of the element ______
cobalt
To classify sediments as lithogenous means that they are derived from ______
preexisting rocks
Lithogenous sediments are primarily composted of clays and the mineral _____
quartz
lithogenous
red clay
The mid-ocean _________ and ________ systems are the most notable features of the ocean floor
ridge; rise
Mid-ocean ridge similar to
rift valley
Sediment between 0.0625 and 2 mm in diameter generally is known as
sand
What resource is the most commonly sought after (in terms of volume) on the sea floor
sand and gravel
Marine sediments are classified according to grain, ________, geographic location, and origin and composition.
size
The steepest part of the continental margin is the continental _________
slope
Measurements of ocean depth have occurred using various techniques for over 2000 years. These measurements are called _________
soundings
Continental slope similar to
submarine canyon
Just like river valleys on land, ______ are V-shaped and formed through the process of erosion. They are believed to be created when ocean levels fall and the continental slope becomes exposed.
submarine canyons
cosmogenous
tekikite
Most ______ sediment is currently accumulating in deltas and estuaries
terrigenous
Siliceous ______ originate from diatoms and radiolaria
tests
The inorganic cell walls of microscopic phytoplankton and zooplankton are called
tests
The thickest deposits of ocean sediment are generally found near ______
the continental margins
What is the primary reason that we continue to drill for oil and gas in offshore fields?
the deposits are very large