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