geology exam 4 Flashcards
plate tectonic processes that produce mountains and volcanoes
constructive
processes that serve as erosional agents
destructive
solid mass moves downhill landslides, rockslides
slides
solid mass rotates and slides downhill
slumps
material flows downhill as separate pieces, not a solid mass soil creep, solifluction, mudflow, debris avalanche
flows
the steepest angle of descent or dip relative to the horizontal plane to which a material can be piled without slumping
angle of repose
a type of creep characterized by the slow, downward progression of rock and soil down a low-grade slope
soil creep
the accumulation of debris in sheets or cones at the bases of rock walls
talus
land area that delivers water, sediment, and dissolved substances via small streams to a major river
watershed
the entire area whose water flows into a particular stream
drainage basin
a triangle-shaped deposit of gravel, sand, and smaller pieces of sediment that forms when a stream gradient decreases suddenly
alluvial fan
the ridge of sand and gravel developed on the inside of a stream meander
point bar
form when water floods out of the channel and spreads out, depositing sediment
flood plain
wetlands that form where a stream flows into a large body of standing water
delta
what is created as the natural movement of a body of water pushes sediment to the side
natural levee
two consecutive crossing points of sinuous and down-valley axes
meander loop
two consecutive crossing points of sinuous and down-valley axes
meander loop
a fluvial process of erosion that lengthens a stream, a valley, or a gully at its head
headward erosion
indicates rocks of equal erodability
dendritic drainage pattern
the greek work for leaf
dendron
indicates alternating bands with different resistance to erosion
trellis drainage pattern
forms in rocks that are cut by a series of perpendicular joints and faults
rectangular drainage pattern
outward stream flow indicates a topographic high (volcano or a similar mountain)
radial pattern 1
inward stream flow indicates a topographic basin
radial pattern 2
consists of a network of river channels separated by small islands
braided stream
shoreline relative to sea level
emergent
shoreline sinking relative to sea level
submergent
the narrow, flat area found at the base of a sea cliff
wave cut cliffs
a landform consisting of steep and vertical columns of rock near a coast formed by wave erosion
sea stacks
a natural arch made of stone created when water wears away the underside of a rock, leaving just the top behind
sea arches
combination of erosion and deposition
tombolos
the largest glaciers and form on large flat areas with abundant snowfall
ice sheets
flow downhill from basic on mountainsides and are typically confined to individual valleys previously carved by streams
valley (alpine) glaciers
indicates the shape change of a material through bending
ductile deformation
indicates the shape change of a material through breaking
brittle deformation
the addition of snow and ice to the glacier, increasing its mass
accumulation
all processes that cause a glacier to lose ice and snow, decreasing its mass (melting, sublimation, calving)
ablation
direct change from ice to water vapor
sublimation
large chunks break off the end of the glacier, forming icebergs
calving
the end of a glacier (may advance, retreat, or stagnate)
terminus
the terminus moves farther from the snowfield when accumulation is greater than ablation
glacial advance
the terminus moves toward the snowfield when ablation is greater than accumulation
glacial retreat
when the flow of new ice is matched by the rate of melting
glacial stagnation
material deposited directly from a melting glacier with very poor sorting
till
material carried away from the glacier by meltwater
outwash
large boulders made from rock types that are different from those in the area they are found
erratic
a ridge of till deposited at the terminus of a glacier during a period of stagnation
terminal moraines
a ridge of till deposited after a glacier retreats from its maximum extent and then stagnates for a while
recessional moraines
a blanket of till deposited from ice
ground moraines
ridges of till formed from blocks of sediment that fell on the alpine glacier from valley walls
lateral moraines
ridges of till formed when lateral moraines from two glaciers merge
medial moraines
a person or thing that precipitates an event
catalyst
