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50 terms

Weathering & Erosion 1

external processes
weathering, mass wasting, and erosion. Processes that happen on earths surface.
internal processes
derive energy from earths interior. mean while, opposing external processes are continually breaking apart rock and moving debris.
the physical breakdown and chemical alteration of rocks at/near earths surface.
mass wasting
the downward movement of rock, regolith, and soil under direct influence of gravity
the physical removal of material by mobile agents(wind, water, ice ).
mechanical weathering
when physical forces break rock into smaller and smaller pieces without changing the mineral composition
chemical weathering
a chemical transformation of rock into one or more new compounds (change in rocks composition)
three physical processes for breaking rock
frost wedging, expansion from unloading, biological activity
frost wedging
the process of water freezing and thawing inside a rock, expanding cracks
talus slopes
large piles forming at the base of steep rocky cliffs
process by which slabs begin to break loose from an exfoliation dome
exfoliation domes
rocks that sheeting occurs on (commonly made of granite)
spheroidal weathering
giving a weathered rock a rounded or spherical shape
differential weathering
when masses of rock do NOT weather uniformly
a common boundary where different parts of a system interact.
layer of rock and mineral fragments produced by weathering
a combination of mineral and organic matter, water, and air
decayed remains of animal and plant life
soil water
water containing many nutrients, far from "pure" water.
parent material
source of weathered mineral matter from which soils develop.
residual soil
soil that forms upon bedrock
transported soil
soil that forms on unconsolidated sediment
slope orientation
the direction a given slope is facing
zones/layers divided into the depths of earths soil
soil profile
displays differentiating horizons
the washing out of fine soil components
when water dissolves minerals carrying them down into deeper zones
"true soil" made up of all horizons
immature soils
soils that lack horizons
soil taxonomy
system used for classifying soil types (12 basic soil orders)
rock cycle
recycling of earth's rocks
secondary enrichment
when important mineral deposits are created by concentrating minor amounts of metals that are scattered through unweathered rock into economically valuable concentrations
event that initiates downward movement
angle of repose
stable angle that particles assume at rest
movement of detached individual pieces of rock
when material remains fairly coherent and moves along a well defined surface
descending material moves in masses along a curves surface of rupture
when material moves downslope as a fluid
rock avalanche
when rock and debris hurtle downslope at speeds exceeding 125 mph
a type of mass wasting that involves the gradual downhill movement of soil and regolith
debris flows mainly composed of volcanic materials on the flanks of volcanos.
form on hillsides in humid areas during heavy precipitation
earth flows in association with earth quakes
slow movements
the subtle forms of mass wasting: creep, solifluction, etc.
when soil is saturated with water, the soggy mass may flow down slope at a rate of a few millimeters/centimeters per day/year (common over permafrost)
permanently frozen ground that occurs on earths tundra
debris flow (mudflow)
mixture of soil, regolith, and water flowing down, following pre-made paths
bedrock breaks and falls down
soil texture
proportion of different particle sizes in soil (clay, silt, sand)
clumps of soil called: platy, prismatic, blocky, spheroidal