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