Geology test 3 – Flashcards

Bathymetry is the study of underwater depth of lake or ocean floors.

The continental margin is the zone of the ocean floor that separates the thin oceanic crust from thick continental crust. Together, the continental shelf, continental slope, and continental rise are called continental margin. Continental margins constitute about 28% of the oceanic area.

The continental shelf is an underwater landmass which extends from a continent

A passive margin is the transition between oceanic and continental lithosphere which is not an active plate margin.

A relatively steep structure that marks the boundary between continental & oceanic crust.

The continental rise is an underwater feature found between the continental slope and the abyssal plain. Merges into a more gradual incline

Bring most of the sediments to the sea floor.

Abyssal fans, also known as deep-sea fans, underwater deltas, and submarine fans, are underwater geological structures associated with large-scale sediment deposition and formed by turbidity currents.

An active continental margin is found on the leading edge of the continent where it is crashing into an oceanic plate. An excellent example is the west coast of South America.

An accretionary wedge or accretionary prism is formed from sediments that are accreted onto the non-subducting tectonic plate at a convergent plate boundary.

Opposite of Accretionary Wedge, it scrapes sediments from the bottom and erodes away.

Area between the margin & the ridge

Long narrow creases in the sea floor that represents the deepest parts of the ocean floor.

Offshore volcanoes form islands, resulting in a volcanic island arc. Generally they result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench.

Parallel to subduction zones that lie adjacent to continental margins.

Flat features of the deep-ocean floor.

Seismic Reflection Profiling is a widely-used technique for using sound waves to image underground rock strata.

Submarine Volcanoes

if volcano grows large enough before being carried away.

Guyots are seamounts that have built above sea level. Erosion by waves destroyed the top of the seamount resulting in a flattened shape.

An extensive region of the ocean floor that is composed of thick accumulations of pillow basalts and other mafic rocks.

A continuous mountainous ridge on the floor of all the major ocean basins.

A long, narrow trough bounded by normal faults. Represents region where divergence is taking place.

The sequence of rocks that make up the oceanic crust.

Basaltic lava that solidifies in an underwater environment.

A large group of nearly parallel dikes

A hydrothermal vent on the ocean floor.

A linear zone along which continental lithosphere stretches and pulls apart.

The idea that the rifting and dispersal of one supercontinent is followed by a long period where new fragments gradually resemble into a new supercontinent.

A point where three lithospheric plates meet

A process where the dense lithosphere sinks into the mantle at a steep angle by its own weight creating a trench.

Lithosphere is too buoyant to subduct spontaneously but is forced beneath the overriding plate.

The process that collectively result in the formation of mountains.

Mountains in which great horizontal forces have shortened and thickened the crust.

A basin that forms on the side of a volcanic arc away from the tench

The region located between a volcanic arc and an accretionary wedge.

A crustal block bounded by faults

Small fragments of continental crust that may lie above sea level.

A zone along with two crustal fragments are jointed together.

Regions with compressional mountain systems where large areas have been shortened and thickened.

A mountain that is formed by the displacement of a rock along a fault.

The concept that earths crust is floating in gravitational balance.

Compensation of the lithosphere when weight is added or removed.

The gradual subsidence of mountains caused by lateral spreading.

The downslope movement of rock, regolith, and soil under direct influence of gravity.

The steepest angle at which loose material remains stationary without sliding downslope.

A type of movement that is common to mass-wasting processes that refers to the free falling of detached pieces.

A movement common to mass-wasting processes in which the material moving downslope remains coherent and moves along a well defined surface.

A type of common mass-wasting processes in which water saturated material moves downslope as a viscous fluid.

Very rapid downslope movement of rock and debris.

The downward slipping of a mass of rock or unconsolidated material moving as a unit along a curved surface.

The rapid slide of a mass of rock downslope, along planes of weakness.

A flow of solid and regolith that contains a large amount of water.

The slow downhill movement of soil and regolith.

The slow, downslope flow of water-saturated materials common to permafrost areas.

The unending circulation of earths water supply.

Removing loosened blocks from the bed of a channel.

Grinding and scraping of rock surface.

The process by which soluble rock is gradually dissolved by water.

Transportation of sediment through a series of leaps or bounces.

A measure of the largest particle a stream can transport

Unconsolidated sediment deposited by a stream.

The zone where all open spaces in sediment and rock are completely filled with water.

Water in the zone of saturation.

The upper level of the saturated zone of groundwater.

A relatively narrow zone at the base of the zone of aeration.

The area above the water table where openings in soil, sediments, and rock are not saturated but filled mainly with air.

The volume of open spaces in rock or soil

A measure of a materials ability to transmit water.

A factor relating to groundwater flow.

Granular, recrystallized snow.

Movement that occurs within a glacier

A mechanism of glacial movement in which the ice mass slides over the surface bellow.

The upper portion of a glacier consisting of brittle ice.

The part of a glacier beyond the snowline, where there is a net loss of ice.

Wastage of a glacier that occurs when a large piece of ice break into the water.

A general term for the loss of ice and snow from a glacier.

Ground up rock produced by the grinding effect.

Scratches and grooves on bedrock caused by glacial abrasion.

A mountain valley that has been widened, deepened, & straightened by a glacier

A tributary valley that enters glacial trough at a considerable height above the floor of the trough.

The most recent period on the geologic time scale.