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26 terms

WEATHERING/EROSION/RIVERS TEST VOCAB

STUDY
PLAY
ABRASION
Mechanical wearing and erosion of bedrock caused by the rubbing, scouring, or scraping action of rock fragments or particles carried by streams, ice, wind, or waves.
ALLUVIAL FAN
Cone-shaped deposit of sediment formed where a fast-moving stream carrying large amounts of sediment flows abruptly onto a level plain, valley floor, or basin.
ATTRITION
Breakdown of rock particles caused by collision with one another as they are carried by the water, wind, or waves.
POINT BAR
The inner portion of a meander, in a stream, where sediment fill is redeposited.
CORROSION
The dissolving of soluble minerals by water in streams or waves; common in humid areas underlain by limestone rocks.
CREEP
Persistent, gradual mass movement of surface soil. Indivisual soil particles are lifted and disturbed by the expansion of soil moisture as it freezes by cycles of moistness and dryness.
DELTA (3 types)
Level area of alluvial deposits formed at the mouth of a river, where it enters a shollow and/or calm water body.
DRAINAGE PATTERN
Arrangment of streams in a region determined by slope, differing rock resistence to weathering and erosion, climatic and hydrologic variability, and structural controls of the landscape.
EXFOLIATION
Rock disintegration of overlaying rocks to expose intrusive igneous rocks such as granite, formed under high pressure below earths surface. (Pressure release)
FALLS
Ooccur when a piece of rock on a steep slope becomes dislodged and falls down the slope. Talus common at the base of slope.
FLOOD PLAIN
A level, gently sloping alluvial plain, found on one or both sides of a stream channel, that is subject to periodic flooding.
FLOWS
Occurs when sufficient force is applied to rocks and regolith that they begin to flow down slope. A sediment flow is a mixture of rock, and/or regolith with some water or air.
FLUVIAL DEVELOPMENT
Stream related processes development
HEADWARD EROSION
Action of a river in cutting its channel upstream, lengthening its valley.
HYDRAULIC ACTION/PRESSURE
Breakdown of solid rocks caused by the sheer weight and high pressure exerted by water in fast flowing streams or strong waves.
HYDROLYSIS
Chemical weathering process in which minerals chemically combine with water; a decomposition process that causes silicate minerals in rocks to break down and become altered.
LATERAL EROSION
Widening of a rover valley by sideways erosion, usually brought about by the undercutting of the banks on the outside curves of meanders.
LEVEE
Ridge of alluvial material found on both sides of a river that stands above the level of the flood plain.
MEANDER
Broad, curving bend in a river flowing over an alluvial flood plain.
OXBOW LAKE
Crescent-shaped lake on a river flood plain formed when a stream cuts through the narrow neck of a meander.
OXIDATION
Chemical weathering in which oxygen combines with certain minerals in the rock to form oxides and hydroxides and leading to the disintegration of rocks.
SCREE/TALUS
Fan-shaped pile of rock fragments that accumulates at the base of steep slopes in mountain ranges where frost shattering is common.
SLIDES
Rocks or debris slide down surfaces, piles of talus are common at the base of a rock slide or debris slide
SOLUTION
Rain water falls through atmosphere disolving small amounts of C02 gas, turning droplets into weak solutions of carbonic acid.
THERMAL EXPANSION
Rocks with crystals expand and contract when heated and coolded. Overtime, exposed rocks develop weakness and disintegrate, forming jagged carpet of rocks over desert surface.
VERTICAL EROSION
Downward cutting action of a river that deepens its bed, often forming a V-shaped valley.