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71 Cards in this Set
- Front
- Back
weathering
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the chemical and physical breakdown of rocks at or near the earths surface
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when does weathering occur?
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when rocks are exposed to air, water, and the actions of living things
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what is the difference between weathering and erosion?
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weathering breaks rocks down without moving them, but erosion moves them
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what does weathering result in?
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residual soil in the same spot where the rock was
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how much of the worlds soil is residual
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5%
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what are examples of ways erosion can occur?
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rivers, wind, glaciers, and gravity from landslides
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what is the soil from erosion called?
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transported soil
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how much of earths soil is transported?
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95%
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chemical weathering
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the breakdown of rock through a change in mineral or chemical composition
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2 examples of chemical weathering
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1. oxidation rusting
2. effect of water on minerals |
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physical weathering
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breaks down rocks of the same material
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when does physical weathering occur?
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when frost action, plant root growth, or abrupt temperature changes causes rocks to crack apart
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4 agents of physical weathering
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1. frostation
2. thermal expansion 3. biologic 4. pressure unloading |
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frostation
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water expands when it freezes
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thermal expansion
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heating and cooling causes rocks to crack
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pressure unloading
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removing surface layers off the rock-rock comes apart
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abrasion
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process where rock particles grind against another rock--physical weathering
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what characteristic of rocks from river beds and beaches is caused by abrasion?
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rounded shape
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what factors affect the rate and type of weathering?
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exposure, particle size, mineral composition, and climate
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in what ways does exposure affect weathing?
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rate and type of weathering
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how does the distance of a rock to earths surface affect weathering?
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the closer a rock is to earths surface, the faster it will weather
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how does particle size affect weathering?
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when particles are smaller, the total surface area per unite volume exposed to weathering is greater, so the rate of weathering is faster
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how does mineral composition affect the rate of weathering?
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different minerals have different physical and chemical properties and weather at different rates
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where is chemical weathering most pronounced?
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in warm, moist climates
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affect of temp. and humidity on chemical weathering
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the higher the average temp and humidity, the more rapid chemical weathering
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what is the most common form of weathering in cold climates?
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frost action
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where is frost action especially intence?
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in moist climate with temp variations that lead to repeated cycles of freezing and thawing
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what are soil layers called?
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horizons
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how can soil be transported into an area from another place?
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wind, moving water, and moving ice of a glacier
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how does soil develop in bedrock?
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originally, there is unweathered bedrock at the surace. soil development, by way of weathering, starts at earths surface and gradually progresses downwartd over time to produce soil layers.
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why is water a major agent of chemical weathering?
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it dissolves many of the minerals that make up rocks
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why are a variety of soil types found in new york states?
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becuase areas of the state differ
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what is the chemical composition of a soil formed in a certain area from the bedrock beneath determined by?
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minerals in the bedrock beneath the soil and the climate of the area
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new york soils are most likely composed of rock particles that have been..
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transported by glaciers or water
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what does erosion do to earths surface over time?
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shapes and lowers it
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4 erosional agents
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1. rivers or running water
2. glaciers 3. gravity 4. wind |
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characteristics of rivers or running water
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rounded particles
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how do the 3 size particles change erosion?
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1. large particles are rolled and bounced
2. small-fine particles called "colloids" are in suspension 3. ions dissolve-solution |
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results of glacier erosion
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-unsorted deposited
-scratched rock -polished rock -parallel groove -u-shaped valley |
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gravity characteristics
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rock becomes angular
rock deposits |
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wind agent
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carries fine particles
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what is river velocity determined by?
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1. slope
2. volume of discharge |
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characteristics of young river
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flows fast
goes straight water falls, rapids carves v-shape valley |
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river bed
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bottom of river
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river banks
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sides of river
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in a straight river, where does it flow fastest?
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in the middle
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why?
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there is no friction with air, sides, or bottom
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where is teh most erosion on the straight river?
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directly below the middle point
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meanders
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bends in the river
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where is the river the fastest when it curves?
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the outside of the curve
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where is it the slowest?
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the inside of the curve
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where is erosion dominant in a curved river?
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on the outside curve
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where is deposition dominant?
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on the inside curvve
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whhat side of the side view is shaded in?
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the inside curve side
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levees
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small deposits that build up on the ride of a river
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base level
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sea level
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characteristics of old age river?
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close to base level
at base level-river slow |
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flood plain
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flat land on sides of old river
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water shed
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all areas that feed one major river system
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how does an ox bow lake form?
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the river curves, then goes straight again and there is a cutoff
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delta
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forms at the mouth of a river from sediments deposited over time from the ever-shifting channel at the streams mouth
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deflation
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removal of the small top loose particles
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sandblasting
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wind causes sand to hit rocks and that will erode those rocks down
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where do glacirs move fastest?
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in the middle
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what kind of valleys do glaciers carve out?
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u-shaped
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what are glaciers erosional features?
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groove,s striations, unsorted rock
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what moves at the same speed as a river?
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dissolved salts (ions)
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how do things carried by a river move in relation to the river?
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move slower
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what happens when an erosional system loses kinetic energy?
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it will drop the sediments its carrying
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horizonal sorting
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as a river slows down, it drops off the largest particles, then the smallest
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when there is maximum KE there is max...
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erosion
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