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64 Cards in this Set
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Sediment, typically with graded bedding, that is deposited by a turbidity current
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turbidite
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How do deep sea fans form?
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Turbidites abound at the mouth of submarine canyons, where they form thick sequences of cone-shaped deposits known as deep-sea fans.
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What carves out deep sea canyons, how?
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Excavated by a combination of sediment slumping and turbidity currents that have deepened a gully, or depression, on the sea bottom.
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Pelagic sediment containing >30% by volume shells of microorganisms
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ooze
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What organisms make up calcareous ooze?
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Zooplankton and phytoplankton
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What organisms make up siliceous ooze?
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Diatoms and radiolaria
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Inorganic deposit that consists of extremely fine-grained particles that typically have a brownish color
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pelagic red clay
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Why is it as hard to erode clays as it is to erode gravels?
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Part of the explanation lies in the fact that mud - a mixture of clay and silt - is more cohesive and, hence, "stickier" than sand, and so a stronger current is needed to dislodge a mud particle from the bottom than a fine grain of sand.
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Which sediment is the easiest to erode?
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sand
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Sediments on the continental shelves
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neritic sediment
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Hydrogenous sediment made up of 2 parts manganese dioxide and 1 part iron oxide
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manganese nodules
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What is the Manganese Nodule Mystery?
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How come the Mn nodules are mostly exposed and there are about the same density of nodules in every layer of sediment?
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Small spheres deposited in high wave activity, as the rolling by waves makes them round as the calcium carbonate is deposited a little at a time
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ooids
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the region of a subduction zone located between the deep-sea trench and volcanic arc, where thick sedimentary units and volcanic rocks are squeezed and wrinkled by compression to form thrust faults and tight holds
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accretionary prism
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Develop along the edges of continents that are located far from the tectonic effects of plate boundaries and have a long history of passive sedimentation
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Atlantic-type margin
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Deposits consisting of >30% by volume of particles produced by organisms, such as shells of diatoms, radiolaria, and foraminifera
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biogenous sediment
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Gravity-induced transport of sediment, such as slumping and turbidity currents
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bulk emplacement
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composed of calcium carbonate
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calcareous ooze
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The depth in the ocean below which material composed of calcium carbonate is dissolved and does not accumulate on the seafloor
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carbonate compensation depth
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Microscopic, unicellular phytoplankton possessing silica valves; they are responsible for much of the ocean's primary production
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diatoms
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Chemically precipitated from seawater, these more-or-less spherical masses, a few millimeters to several centimeters in diameter, are composed of concentric layers of iron, manganese, and other metal oxides
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ferromanganese nodule
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Planktonic and benthonic protozoans that have a test composed of calcium carbonate
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foraminifera
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Vertical grain-size gradation in a layer of sediment, typically with the coarsest particles at the bottom of the bed, the finest at the top
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graded bedding
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particles that are precipitated by chemical or biochemical reactions in seawater near the sea floor; manganese and phosphate nodules are examples
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hydrogenous sediment
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An opening in the ground from which pour out hot, saline water solutions
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hydrothermal vents
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The transport of sediment to the deep sea by floating icebergs which melt and drop their sediment load
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ice rafting
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A sedimentary rock composed dominantly of calcium carbonate, either precipitated from seawater or deposited as shell debris
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limestone
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Dominated by a subduction zone and are built up of highly deformed sedimentary beds that may be interlayered with lavas and volcanogenous sediment
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Pacific-type margin
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The inorganic deposit that contains extremely fine-grained particles that typically have a brownish color
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pelagic clay
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Deep-sea sediment that accumulates on the seafloor by the slow settlement of grains through the water column
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pelagic sediment
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A hydrogenous deposit consisting of nodules or crusts of P2O5
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phosphorite
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Microscopic, unicellular planktonic and benthic animals that possess siliceous tests
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radiolaria
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Sand sediments that are buried, the grains are compacted, cemented, and slowly transformed into sedimentary rock
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sandstone
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Mud sediment that is buried, the grains are compacted, cemented, and slowly transformed into sedimentary rock
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shale
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Material whose composition is silica
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siliceous ooze
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The sliding of large, cohering blocks of sediment or rock downslope under the influence of gravity
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slumping
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The branch of geology that studies the relationship and significance of layered sedimentary rocks
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stratigraphy
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Sediments derived from the mechanical weathering of rocks on land
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terrigenous sediment
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Poorly sorted sediment that is deposited by glaciers
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till
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Sediment, typically with graded bedding, that is deposited by a turbidity current
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turbidite
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A density-driven slurry of sediment-laden water which flows swiftly downhill displacing less dense water
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turbidity current
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Sediment derived from volcanoes
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volcanogenous sediment
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A tilted zone of earthquakes associated with collisional plate boundaries known as subduction zones
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Benioff zone
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A force that pushes together parts of a rock or structure, decreasing its volume
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compressional stress
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The process whereby continents are and have been in motion relative to one another across the Earth's surface
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continental drift
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Plates that extend downward through the brittle outer shell of the Earth that includes the crust and uppermost mantle
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lithospheric plate
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The relatively cool, brittle, outer shell of the earth, some 100 kilometers thick, that includes the crust and uppermost mantle
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lithosphere
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Long, linear bands of basalt crust that lie parallel to a spreading ocean ridge and that are alternately normally and reversely magnetized
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magnetic anomaly stripe
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The upwelling of hot material into and through the lithosphere, with magma spilling out onto the Earth's surface and building thick volcanic piles
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mantle plume
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Oriented as it is at present
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normal polarity
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This "fossil" magnetization is quite stable over geologic time, particularly in basalts, and provides a clear magnetic record unless the rock has been reheated or deformed
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paleomagnetism
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The study of fossils
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paleontology
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The megacontinent of the Mesozoic Era that consisted of all of the present-day continents joined together into a single unit
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Pangaea
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The theory that the Earth's lithosphere is divided into broad, irregular plates that are either converging, diverging, or slipping by one another
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plate tectonics
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Oriented in the opposite direction
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reverse polarity
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The fault-bounded valley found along the crest of many ocean ridges; it is created by tensional stresses that accompany the process of sea-floor spreading
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rift valley
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The process by which basaltic crust is created at the crest of ocean ridges where lithospheric plates are diverging
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sea-floor spreading
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The distribution, frequency, and magnitude of earthquakes in an area
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seismicity
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A high-angle fault, such as a transform fault, along which rocks move horizontally
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strike-slip fault
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A collisional plate boundary along which one lithospheric overrides another and produces a deep-sea trench, a volcanic arc, and seismicity
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subduction zone
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Term that denotes deformation of the crust
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tectonism
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"pull-apart" force
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tension
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heat transfer by fluid motion
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thermal convection
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A steep boundary separating two lithospheric plates along which there is lateral slippage
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transform fault
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