Chapter 6: Ocean Sediments
ooze
(of a thick liquid) pass or flow slowly; N: mud or thick liquid as at the bottom of a river
Diatoms
A unicellular photosynthetic algae with a unique glassy cell wall containing silica
mollusk
An invertebrate with a soft, unsegmented body; most are protected by a hard outer shell.
grain size
the size of the grains that make up a rock, which helps to classify the type of rock
Runoff
water that flows over the ground surface rather than soaking into the ground
turbulence
wild or disturbing activity
weathered
worn by long exposure to the air; weather-beaten.
wetland
A land area that is covered with a shallow layer of water during some or all of the year
Delta
A landform made of sediment that is deposited where a river flows into an ocean or lake
glacier
A large mass of moving ice and snow on land
Fjord
A long narrow inlet from the sea between steep cliffs or hills
graded beds
A sediment layer characterized by a decrease in sediment size from bottom to top.
Fossil
A trace of an ancient organism that has been preserved in rock.
slump
A type of mass movement that occurs when a mass of material moves down a curved slope
Adsorption
Assimilation of gas, vapor, or dissolved matter by the surface of a solid or liquid.
detritus
Dead organic matter
Pelagic
Describing organisms that live in the water column away from the ocean bottom.
Radiolaria
Heterotrophic single-celled protists with a porous shell of silica and long cytoplasmic extensions.
colloidal
pertaining to a gluelike substance
Foraminifera
Marine protozoans that have variably shaped shells with small holes.
Phytoplankton
Microscopic, free-floating, autotrophic organisms that function as producers in aquatic ecosystems
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
relict sediments
On continental shelf; do not change with the environment
decomposers
Organisms that break down the dead remains of other organisms
Frustule
the shell of a phytoplankton that is made up of silicon (glass)
Deposition
Process in which sediment is laid down in new locations.
Erosion
Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)
fecal pellets
Sand-sized grains found in carbonate mud that have passed through the guts of invertebrate organisms.
contiental shelf
Sandy, gently sloping underwater plain boarding the coast of a continent is?
terrigenous sediment
Sediment derived from the land and transported to the ocean by wind and flowing water.
Biogenous
Sediment that is made up of the skeletons and shells of marine organisms.
residence time
The average time a given particle will stay in a given system
Carbonate Compensation Depth (CCD)
The depth in the ocean below which material composed of calcium carbonate is dissolved and does not accumulate on the seafloor.
electrostatic
The force between electrically charged objects.
Zooplankton
Tiny floating organisms that are either small animals or protozoa.
pore water
Water that is left in the clay even though it may appear completely dry.
lagoon
a body of water cut off from a larger body by a reef of sand or coral
Diagenesis
a collective term for all the chemical, physical, and biological changes that take place after sediments are deposited and during and after lithification
sorted sediments
a deposit of sediments that are similar in size (or shape, or density); the greater the similarity of particles the more sorted the sediments
turbidity current
a downslope movement of dense, sediment-laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension
abyssal plain
a large, flat, almost level area of the deep-ocean basin
submarine canyon
a seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower, or a canyon carved into the outer continental shelf, slope, and rise by turbidity currents
limestone
a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals
Coastal Plain
area of flat land along a sea or ocean
siliceous ooze
biogenous sediment composed of the silica based shells of single-celled animals and algae
Cosmogenous
derived from outer space
Turbidites
graded layers of terrigeneous sand interbedded with finer pelagic sediments of the deep sea floor
shore
land bordering the sea, a lake, or a large river
calcareous
made of calcium carbonate
Coccolithophores
microscopic algae with calcium carbonate shells, form the base of many marine food webs
hard parts
parts of organisms most likely to become fossils
biochemical cycle
process in which elements, chemical compounds and other forms of matter are passed from one organism to another
marginal sea
relatively large semi-isolated body of water
Leaching
removal of dissolved materials from soil by water moving downwards
Hydrogenous
seafloor sediment consisting of minerals that crystallize from seawater
lithogenous
sediment made of rocks eroded from the continents by water wind waves
Evaporites
sedimentary rocks formed from minerals left after water evaporates
excreted
separate and expel as waste
Pteropods
small, graceful, swimming snails
hydrothermal vents
spots on the ocean floor where hot gases and minerals escape from earth's interior into the water
cohesive
sticking or holding together; unified
Bioturbation
the disturbance of sedimentary deposits by living organisms