Download Weathering Erosion Deposition Landscapes Stuff to Know

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Weathering Erosion Deposition Landscapes Stuff to Know
Weathering (notes p 1, 2, 3)
• Types of weathering
o Physical: exfoliation, frost wedging (frost action), plant action, abrasion
and how they occur.
o Chemical: carbonation, hydration, oxidation, plant acids, acid rain and
how they occur.
How climate affects rate of weathering (notes p 3)
• Climate is overall temperature and precipitation in an area and climate affects the
type and amount of weathering.
• Chemical weathering occurs most rapidly in warm, humid climates
• Arid landscapes are more physically weathered (angular) whereas humid
landscapes are more chemically weathered (rounded)
Resistance to weathering (notes p 5)
• Because of rock type and climate, rocks can be more or less resistant to
weathering. More resistant rocks stick out more or make cliffs.
• The more rock is broken down, the greater the surface area and the faster the rate
of weathering.
Products of weathering (notes p 6,7)
• Weathered rock results in sediments (sizes are on page 6 in Ref Tbl)
• Rocks can be dissolved by water. All water is mineral water.
• Soil is a product of weathered rock and biological activity.
• Soil horizons A, B, and C have different properties (know them)
• Most soils on earth have been transported, moved around by erosion.
Erosion and Deposition by Gravity (notes p 10)
• Gravity is the force behind all agents of erosion
• Gravity working alone creates mass wasting
• Types of mass wasting include landslides, rock slides, soil slumping, mudslides
Erosion and Deposition by Wind (notes p 6, 7, 8)
• Wind carries small sized particles like sand
• Wind that carries sediments “sandblasts” rocks that it encounters leaving them
with a flat, pitted, and frosted appearance (ventifact)
• Sand dunes are depositional features of wind driven sediments and they migrate
(wind and sand moves up the ramp side and sand moves over the cliff side of the
dune)
• Abrasion of rocks can leave rocks with a mushroom or arch shape
Erosion and Deposition by Running Water (notes p 10, 11, 12, 13, 14)
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The steeper the river, the faster the velocity (speed/ rate).
The more water flowing in a river (greater volume/ discharge) the faster the
velocity (speed/ rate).
In a straight channel, the fastest water flows down the middle. On a meander, the
fastest water flows on the outside of the curve. In both cases, the fastest water is
right below the surface above the deepest part of the channel.
More erosion occurs on the outside curve of a meander.(water moves faster there)
More deposition occurs on the inside curve of a meander. (water moves slower
there)
Water moves floating sediments and particles, dissolved sediments (in solution),
sediments that remain in the water column (suspension), and particles that bounce
along the bottom (saltation)
Abrasion of sediments in a river makes them smaller and rounder
Page 6 in the Ref Tbls. Shows the speed necessary to transport different sized
sediments
Larger particles settle faster than smaller.
Rounder particles settle faster than flatter.
More dense particles settle faster than less.
If sediments of mixed sizes fall into a still body of water, the sediments are sorted
by size, shape, and density.
Horizontal sorting occurs in a delta situation where a river flows into a lake or
ocean. The largest sediments settle first and the clay are the last to settle far away
from the mouth of the river.
An alluvial fan is like a delta on land. Example is Death Valley where sediments
from meltwater transports sediments to the desert floor, where the water
evaporates and leaves the sediments in a pile.
An oxbow lake is a meander in a river that got cut off, creating a horseshoe
shaped lake.
A levee is a ridge of sediment along the banks of rivers that forms when flooding
deposits sediments on the edges.
A flood plain is the plain surrounding a river where sediments are deposited
during flooding.
Rivers or streams make “V”-shaped valleys
Drainage patterns (notes p 14)
• There are 4 different drainage patterns that are based on the way that water flows
off of different landscapes: 1) “radial” is a pattern like sun rays out from a center
point that results from water flowing off of a hill or cone volcano 2) “annular” is
a circular pattern of drainage that results from water flowing off of an eroded
dome 3) “dendritic” is a branching pattern resulting from water flowing off of a
gentle slope or plain 4) “trellis” is a parallel pattern of drainage resulting from
water flowing in the low points between ridges (can be from folded rock)
Glaciers (notes p 15, 16, 17, 18)
• Continental glaciers covered major portions of the continents during ice ages.
• Now we have the remnants of the last ice age over Antarctica and Greenland in
the form of sheets of continental ice.
• Continental glaciers melt they leave evidence behind on the land that they once
covered. These features include: kames, drumlins, erratics, kettle lakes, braided
rivers, outwash plains, moraines, till, eskers
• Till is unsorted material left from the glacier.
• Glaciers can also leave rock polished (glacial polish) or leave rock with parallel
scratches (striations) that were caused by rocks embedded in the ice that scratched
the underlying rock.
• The Finger Lakes, Great Lakes, Niagara Falls, and Long Island all formed as a
result of the last glacial period.
• Valley glaciers are rivers of ice that appear high in mountains all over the world.
• Valley glaciers carve out u-shaped valleys in the mountains.
• Valley glaciers also leave other features like: hanging valleys, arêtes, horns,
cirques, and moraines
Landscapes
• Plains are low elevation, low relief, and horizontal sedimentary rock
• Plateaus are mid to high elevation, mid to high relief, and horizontal sedimentary
rock
• Mountains are high elevation, high relief, and distorted metamorphic rock (with
some igneous and sedimentary rocks)
• There are different landscape regions in NY state that are shown on Ref. Tbls. p 2
• Rock type and rivers and towns can be found on Ref. Tbls. p 3