OCEN-1010 Chapter 3

Bathymetry is the _____.

discovery and study of ocean-floor topography

ocean basin

deep-ocean floor made of basaltic crust

Lithification

conversion of accumulated particles into rock by pressure or introduction of a mineral cement

active margin

submerged outer edge of a continent near an area of lithospheric plate convergence

The shallow submerged extension of a continent is called the abyssal plain.

False

_____ sediments are minerals that have precipitated out of water.

Hydrogenous

_____ are hot springs found on active oceanic ridges.

Hydrothermal vents

Bathymetry

The discovery and study of submerged contours.

1. During a piteraq, a torrent of cold air sweeps down off the Greenland ice cap, thundering down the steep slopes of ice-covered mountains and creating an avalanche of freezing winds that can reach hurricane intensity.

True

Bathymetry is the discovery and study of ocean-floor topography.

True

abyssal plain

flat, cold, sediment-covered ocean floor between wedge of sediment and young seabed

The continental rise is _____.

found along passive margins where the oceanic crust at the base of the continental slope is covered by an apron of accumulated sediment

continental shelf

gradually sloping submerged extension of a continent composed of granitic rock overlain by sediments

Terrigenous sediments come from ______.

land erosion, volcanic eruptions, and blown dust

Passive margins are often composed of a continental shelf, continental slope, and continental rise;

...

Very few areas along the ocean floor are altogether free of overlying sediment. What could be the reason sediment does not collect in these areas?

Strong currents may scour the sediments away.

Biogenous sediments were originally brought to the ocean in solution by rivers or dissolved in the ocean at oceanic ridges.

True

Hydrothermal vents are hot springs on oceanic ridges associated with active seafloor spreading.

True

Marine sediments dominate the seafloor landscape and play an important role in understanding oceanographic processes.

True

Most neritic sediments are terrigenous; they are eroded from the land and carried to streams where they are transported and deposited along the continental shelf.

True

Oceanic crust at the base of the continental slope is covered by an apron of accumulated sediment called the continental rise.

True

Paleoceanography is an emerging science that studies the layers of the ocean to interpret ocean and climate history.

True

Submarine canyons cut into the continental shelf and slope, often terminating on the deep seafloor.

True

Terrigenous sediments are the most abundant on the Earth.

True

The accuracy of echo sounding can be affected by water conditions and bottom contours.

True

The continental slope is the transition between the gently descending continental shelf and the deep-ocean floor.

True

terrigenous sediment

accumulated particles derived from land and transported to the ocean by wind and flowing water

hydrogenous sediment

accumulated particles formed directly by precipitation from seawater;also called authigenic sediment

ooze

accumulated particles of at least 30% biological origin

biogenous sediment

accumulated particles of biological origin

cosmogenous sediment

accumulated particles of extraterrestrial origin

trench

arc-shaped depression in deep-ocean floor with very steep sides and sediment-filled bottom

_____forms mainly from shells of the amoeba-like foraminifera; small, drifting molluscs called pteropods; and tiny algae known as coccolithophores.

calcareous ooze

The _____ is the depth where the rate at which calcareous sediments are supplied to the seabed equals the rate at which those sediments dissolve.

calcium carbonate compensation depth

Seamount

circular or elliptical projection from the seafloor more than 1 kilometer (0.6 mile) in height

Passive margins are _____.

continental margins facing the edges of diverging plates with little earthquake or volcanic activity

Island arc

curving chain of volcanic archipelagos and seafloor projections found paralleling concave edge of arc-shaped depression

Submarine canyons _____.

cut into the continental shelf and slope, often terminating on the deep seafloor in a fan-shaped wedge of sediment

calcium carbonate compensation depth (CCD)

deepness where the rate at which calcareous accumulated particles amass equals rate of their dissolution

A guyot is an arc-shaped depression in the deep-ocean floor.

false

Seamounts are flat, featureless expanses of sediment-covered ocean floor found on the periphery of all oceans.

false

Another driving force for piteraqs is

gravity

The first echo sounders were used for _____.

iceberg and ocean depth detection

2. The trigger for the formation of piteraqs seems to be _____.

low pressure systems

sediment

particles of organic or inorganic matter that accumulate in a loose, unconsolidated form

When continental crust transitions to oceanic crust near a diverging plate boundary, it is known as

passive margin

submarine canyon

runs roughly perpendicular to shoreline and cuts across edge of submerged extension of a continent

continental rise

sediment wedge that forms gentle transition between edge of continental incline to sediment-covered ocean floor

The continental shelf is the _____.

shallow, gently sloping, submerged extension of a continent

The top of Mt. Everest, the world's highest peak, is composed of _____.

shallow-water biogenic marine limestone

continental slope

sloping transition between the granite of the continent and the basalt of the seabed

hydrothermal vent

spring of hot, mineral- and gas-rich seawater found on some young seabeds

passive margin

submerged outer edge of a continent near area of lithospheric plate divergence

The shape of oceanic ridges are dependent on the speed that the ocean floor on either side moves away from the ridge. If seafloor spreading is relatively slow, the ridge will likely be relatively

tall and narrow

Continental margin

the submerged outer edge of a continent made of granite crust

active margins may not contain a continental rise because sediments fall into a _________ at the base of the continental slope

trench

The ocean floor is characterized by bathymetric features that are generally the result of plate interactions and sedimentation. As plates come together,_______ can form.

trenches

The average depth of the ocean is much greater than the average elevation of the continents.

true

Turbidty current

underwater "avalanche" of abrasive sediments thought responsible for the deep sculpturing of V-shaped valleys

guyot

volcano that is flat-topped, submerged and dormant

oceanic ridge

young seabed at the active spreading center of an ocean, often unmasked by sediment