Oce1001: Test 1 Exploring the Depths of the Pacific Ocean Part 2

they are transform plate boundaries.

An example of a fracture zone is the Mendicino Fracture Zone, which is offshore past the end of the San Andreas Fault and oriented nearly perpendicular to the California coast.

Atlantic, Arctic, Indian, and Pacific Oceans.

The depth of the trench is estimated at 17,500 m.

differing densities of the rock and mineral materials.

basalt.

Continental crust is thicker and less dense than oceanic crust.

shelves

Continental shelves are the relatively flat areas that adjoin most continents.

HINT The answer rhymes with what Santa's helpers are called (plural).

sonar

Side-scan sonar uses transmitters directed away from both sides of the ship to map strips of ocean floor up to 60 km wide.

HINT Bats use this to "see."

margin

The continental margin is composed of rift blocks of continental crust that gradually become covered by thick masses of sediment.

HINT This is also an area on a piece of notebook paper.

passive

The east coast of North America is considered to be a passive margin because there is little associated seismic activity. This is in contrast with an active margin, such as the west coast of North America.

HINT It's the opposite of active.

turbidity

Turbidity currents, flows of sediment-laden water, periodically move down the continental slope and cut deep canyons.

HINT These are underwater avalanches that lift and suspended sediment.

Pillow

The smooth, rounded texture of pillow lavas suggests that there was sudden chilling of lava by contact with cold seawater.

HINT The texture of these lavas is said to resemble an item that you use to lay your head on when sleeping.

transform

Fracture zones are the extensions of transform faults that exist beyond the offset segments of the mid-ocean ridge.

HINT The San Andreas is an example of this type of fault on land (but the word is not "strike-slip").

trenches

Ocean trenches, created by plate convergence, are the deepest parts of the sea floor.

HINT Rhymes with "benches" (plural).

tablemounts

Tablemounts have flattened tops that were created by wave activity at the ocean surface.

HINT Think about where you normally sit to eat a meal (plural).

Ring of Fire

The trenches that occur along the margins of the Pacific Ocean are associated with subduction zones and volcanic arc volcanism, which are the dominant features of the Pacific Ring of Fire.

HINT This was named because it appears on a world map as a very large circular structure that has an abundance of the world's volcanic (and earthquake) activity.

west

The west coast of South America is considered to be a convergent-active continental margin because of the convergent plate boundary and associated trench/continental arc.

HINT It's a compass direction (not left or right).

mid-ocean ridge

Black smokers are associated with the crest of the mid-ocean ridge.

HINT It's commonly abbreviated MOR (don't forget the dash!).

made of material derived from the continents.

Lithogenous sediments are primarily weatheredmineral grains.

along the mid-ocean ridge beneath warm surface waters

Remember that calcareous sediments will not form below the CCD.

False

Consider the process by which lithogenous sediments are transported.

False

Oolites are onion-shaped carbonate precipitates that occur in shallow, warm water.

high clay content.

Maturity can be caused by increased time of transport from source to deposit.

all of the above.

Oozes contain at least 30% skeletal remains from marine microorganisms.

a type of foraminifer.

Manganese is a metal that occurs as nodules on the sea floor.

diatoms

Their skeletons are made of silica.

being concentrated in fecal pellets.

Consider effective transport agents.

calcium carbonate dissolves in seawater.

The physical conditions below the CCD cause something to happen to calcium carbonate material (such as calcareous ooze).

to have it accumulate faster than it dissolves.

Remember that silica is unaffected by the CCD but is constantly and slowly dissolving in seawater.

warm; cool .

Think of where the organisms live that produce the deposits on the sea floor below.

abyssal clay

For sediment sizes, consult the Wentworth scale of grain size for sediments (Table 4-2, page 105 in the text).

all of the above are true.

Integrate your new knowledge of tectonics, paleomagnetism, and sediment deposition to answer this question.

coccoliths

Chalk is made of once-living microscopic photosynthetic organisms that make their hard shells out of calcium carbonate.

lithogenous

Lithogenous sediments are derived from pre-existing rock material.

HINT Remember, "litho" means rock.

grain

The Wentworth scale is a grain size scale used to provide a standard naming scheme for particles.

HINT The answer rhymes with "brain."

neritic

Neritic (literally, "of the coast") deposits are those sediments that are found close to shore.

HINT This is the opposite of pelagic deposits.

biogenous

Biogenous sediments, such as calcium carbonate or silica (opal), are derived from the hard remains of once-living organisms.

HINT Remember, "bio" means life.

Diatoms

Microscopic algae called diatoms, along with radiolarians (protozoans), comprise most siliceous biogenous particles.

HINT These are the organisms that make up "diatomaceous earth" (plural).

4500

The average depth of the CCD is 4500 meters.

HINT It's a four-digit number with no commas that's equal to about 15,000 feet.

hydrogenous

Hydrogenous deposits, such as manganese nodules, form as the result of chemical reactions that take place in the water or from interactions between seawater and sediment.

HINT Manganes nodules are round hard lumps of metal-rich material that precipitate directly from seawater.

cosmogenous

Cosmogenous particles originate from outer space, and commonly include nickel-iron spherules and silicate chondrules.

HINT Space is sometimes referred to as the cosmos.

lithogenous

Lithogenous sediment deposition precludes the formation of an ooze, which is pelagic and must have greater than 30% by weight of biogenous material.

HINT Oozes do not contain very much material derived from rocks.

hydrogenous

Halite, anhydrite, and gypsum form by evaporation of seawater and are examples of hydrogenous sediments.

HINT These minerals form by precipitating directly from the dissolved materials in seawater.

biogenous

Radiolarian ooze is a biogenous sediment that contains at least 30 percent radiolarian tests.

HINT Remember what type of sediment includes the hard remains of once-living organisms.

lithogenous

Black volcanic beach sand is lithogenous sediment because the material that comprises the sand was originally from rock material.

HINT Even though black volcanic beach sand can form by lava flowing into the ocean, the material that comprises the sand was originally from rock material.

lysocline

The depth at which calcium carbonate first begins dissolving is called the lysocline.

HINT This is not the CCD, which is deeper below. This word is derived from "a loosening" plus "slope" (1 word).

dissolves

At the CCD, supply rate = dissolution rate. Below this depth any calcium carbonate in the water dissolves.

HINT The water below the CCD is undersaturated with regard to calcium carbonate, so this chemical reaction takes place (plural).

methane

Methane hydrate is the most common type of gas hydrate.

HINT This gas has a chemical formula of CH4.