oceanography chapter 4
Describe the origin, composition, texture, and distribution of lithogenous sediment
-Lithogenous sediment is derived from pre-existing rock that is weathered and transported to the oceans by streams, wind, glaciers, and gravity from land. -The composition of lithogenous sediment reflects the material from which it was derived. -The size of the sediment particles is dependent on the energy needed to lay down the deposit, as well as its sorting. -Lithogenous sediment can be found nearly everywhere on the ocean floor
responsible for the creation of siliceous ooze
-Radiolarians
considered hydrogenous
-manganese nodules
where would you expect to find large amounts of lithogenous sediment
-on the continental shelf
difference between neritic and pelagic deposits
Neritic (of the coast) deposits are found on continental shelves and in shallow water near islands; these deposits are generally coarse grained. Pelagic (of the sea) deposits are found in the deep-ocean basins and are typically finer-grained materials
Which of the following conditions allows for calcareous ooze to be found beneath the CCD
The ooze accumulates above the CCD and then is covered before being transported to deeper depths by sea floor spreading
two major chemical compounds that comprise most biogenous sediment
The two most common chemical compounds in biogenous sediment are calcium carbonate (produced by foraminifers and coccolithophores) and silica (produced by diatoms and radiolarians)
Oozes are uncommon on continental margins because
the biogenous component tends to be overwhelmed by the amount of lithogenous material derived from the nearby continent
All of the following are true concerning neritic sediment deposits except
they are primarily composed of calcareous deposits of biological origin
Sediments with all grains of about the same size are classified as
well sorted
Marine sediments provide valuable clues about which of the following Earth history events
-previous ocean circulation patterns
Which of the following is not an important control on oceanic sediment accumulation
All of the above factors are important
Describe the process of how a deep-sea drilling ship such as the JOIDES Resolution obtains core samples from the deep ocean floor.
This ship has a tall metal drilling rig to conduct rotary drilling. The drill pipe is made up of individual sections that can be screwed together to make a single string of pipe. The drill bit, located at the end of the pipe string, rotates as it is pressed against the ocean bottom. A core can then be raised to the surface from inside the pipe
Sediments that are poorly sorted were most likely deposited by
a glacier
The most likely place to find abundant manganese nodules is on the
abyssal plain far from a continent
ice rafting
associated with glacial deposits
turbidite
associated with submarine canyons and deep-sea alluvial fans
coccolithophores
biogenous sediment
siliceous ooze
biogenous sediment
You take a sediment sample from the ocean floor at a depth of 5500 m. The area has low biological productivity and the CCD is at 4500 m depth. Your sample will probably consist of
clay
Ocean sediments provide all of the following mineral resources except
coal
Sediments with an extraterrestrial origin are called
cosmogenous
tektites
cosmogenous sediment
oolites
does not fit
siliceous ooze
does not fit
tektites
does not fit
calcium carbonate (CaCO3)
foraminiferans
halite
hydrogenous sediment
metal sulfides
hydrogenous sediment
Salt beds of the U.S. Gulf Coast are
hydrogenous sediments
Pelagic clays contain lots of material that settles to the seafloor through the water column and are
less than 30% biogenous material
Sediments derived from pre-existing rocks on land are called
lithogenous
Sediment that begins as rocks on continents or islands is called
lithogenous (terrigenous) sediment
Calcium carbonate is most likely to dissolve in water with which characteristics
lots of carbon dioxide and colder temperatures
Sediments found on continental margins are called
neritic
The most abundant mineral in lithogenous sediments is
quartz
All of the following are hydrogenous sediments except
stromatolites
The particles found in some sediment that suggests that an extraterrestrial impact event are
tektites
