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Texas A&M University, Corpus Christi *
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3351
Subject
Geology
Date
Apr 3, 2024
Type
docx
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6
Uploaded by AgentResolveDinosaur6
Physical weathering of the ocean floor occurs primarily
by waves and currents
, whereas dissolution of minerals dominates chemical weathering.
Choose the two most important agents of physical change on the deep-sea floor.
Rain of fine sediment
Volcanism
Drag and drop the definitions against the corresponding terms associated with continental margins.
Continental margin
--
Where land meets the ocean
Passive margin
---
Where the continent-ocean transition is not a plate boundary
Active margin
----
Where the continent-ocean transition is a plate boundary
Continental shelf
--------
The submerged flat borders of the continent that slope very gently away from the shoreline
Two of the following sentences describe active margins and two describe passive margins. Choose the two active margin descriptions.
The continental shelf is narrow.
The transition from continent to ocean is also a move from one tectonic plate to another.
A - Continental slope
B - Continental shelf
C - Continental rise
Which of the following describe weathering of the sea floor?
Both chemical and physical weathering occur.
Weathering occurs more slowly than on land.
Weathering is more rapid along coastlines.
Because they are under water, continental shelves are considered to be part of the ocean crust. False
The two most important agents of physical change on the sea floor include the constant rain of sediment and volcanism,
Starting at the beach and moving seaward, put these features in the correct order in
which you would encounter them (assuming you could walk on the sea floor).
Shelf
Shelf Break
Slop
Rise
Active
margins commonly are marked by volcanoes and earthquakes, whereas
passive
margins have little, if any, tectonic activity.
Which of these features is not part of the continental margin?
Continental stairs
Abyssal plain
A continental shelf is
WIDER
____ than the water is deep.
Which of the following describe continental slopes?
Might have submarine canyons
May show rocky outcroppings
Are steep
Two of the following sentences describe active margins and two describe passive margins. Choose the two active margin descriptions.
The transition from continent to ocean is also a move from one tectonic plate to another.
The continental shelf is narrow.
Because they are under water, continental shelves are considered to be part of the ocean crust. FALSE
The abyssal plain, or flat portion, of the sea floor is littered with hills and mountains,
many of which are volcanic in origin. Which of the following are the names of some of these features?
Seamounts
Guyots
Abyssal hills
The two most important agents of physical change on the sea floor include the constant rain of sediment and volcanism
.
What features of the ocean floor are over 40,000 miles (65,000 kilometers) long and
are found running through every ocean? Ridge and rise systems
The steepest part of the continental margin is the continental
slope
.
The deep-sea floor receives a constant but slow supply of sediment.
The thickness, composition, distribution, and source of
ocean sediments provide oceanographers with valuable information on how Earth functions over long time scales.
Which of these features is not part of the continental margin?
Continental stairs
Abyssal plain
Match the sea floor terms with the appropriate definitions.
Abyssal plains: The flat, deep portions of the ocean floor
Seamounts: Steep-sided volcanoes on the ocean floor that may breach the surface
Abyssal hills: Very common features, less than 1000 m high
Guyots: Flat-topped, underwater features found at least 1000 m below the surface
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Marine sediments are classified using which of the following three characteristics?
Multiple select question.
Geographical location
Size
Origin and composition
The mid-ocean ridge and rise systems are the most notable features of the ocean floor.
Arrange, in descending order, the following sediments in terms of their particle size.
Place the sediment with the largest particle size at the top.
Boulder, Pebble, Send, Silt, Clay
The thickest deposits of ocean sediment are generally found near
Blank______.
the continental margins
The thickness of pelagic sediments
increases
with increasing distance from mid-
ocean ridges.
Identify the ways in which ocean sediments can be used as direct evidence in
solving different type of issues. To find offshore mineral resources
To map offshore pollution patterns
To identify sites for underwater construction projects
Lithogenous sediments, those that are derived from preexisting rocks, are often also
described as terrigenous, meaning that they are derived from
land
Biogenous sediments are derived from
organisms
______.
Marine sediments are classified according to grain
size
, geographic location, and origin and composition.
Sediment smaller than 0.0625 mm in diameter cannot be seen unaided and is called
mud or silt
. Sediment between 0.0625 and 2 mm in diameter generally is known as
sand
, and grains larger than 2 mm are called
gravel
.
Pelagic
sediments are those that are fine-grained and collect slowly on the deep-
sea floor.
To classify sediments as lithogenous means that they are derived from preexisting rocks.
Pelagic sediments with over compensation % biogenous material are known by the general name of
ooze
.
Biogenous sediments are derived from organisms.
The
carbonate compensation depth (CCD)
is the depth at which the amount of calcareous material preserved falls below 20% of the total sediment.
Marine sediments are classified using which of the following three characteristics?
Origin and composition
Size
Geographical location
who studies the sediments of the oceans to recreate geologic history works in a field of study called paleoceanography
.
Isotopes are atoms of the same element that have a different
number of neutrons in the nucleus.
Different types, or isotopes, of oxygen exist in the ocean and are incorporated into the skeletal fragments of animals. What can the ratio of preserved isotopes tell us about climate?
Certain ratios of oxygen reflect either warmer or cooler ocean temperatures.
Which of the following correctly describe sand and gravel resources found on the sea floor?
Sand and gravel is mostly mined for use in construction.
Sand is mined as a source of metals.
How does the carbonate compensation depth (CCD) affect accumulation of calcareous ooze on the ocean floor?
Ooze accumulates at depths above the CCD.
The CCD has an average depth of about 4500 m (14,800 ft).
______ is a seabed resource used to produce fertilizers. Phosphorite
Of all seabed resources extracted from the sea floor or below,
Blank______ represent
more than 95% of the value.
oil and gas
isoptopes are atoms of the same element that have a different number of neutrons in the nucleus.
What are gas hydrates? Solid, icelike structures composed primarily of methane
A high ratio of
18
O:
16
O in marine organism shells preserved in ocean floor sediments indicates
colder, glacier periods
What resource is the most commonly sought after (in terms of volume) on the sea floor?
Sand and gravel
Phosphorite is a seabed resource used to produce fertilizers.
Which of the following represent the highest valued resources extracted from the sea floor or below?
Oil and gas
Gas hydrates are solid, icelike structures composed primarily of methane that are formed in high-pressure locations such as the deep-ocean floor.
Which of the following correctly describe sand and gravel resources found on the sea floor?
Sand and gravel is mostly mined for use in construction.
Sand is mined as a source of metals.
margins commonly are marked by volcanoes and earthquakes, whereas
margins have little, if any, tectonic activity.
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