Weathering Erosion Deposition—Main Points
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Weathering is the breakdown of rocks o Physical Weathering just breaks rocks into smaller pieces
 Frost Action/Frost Wedging—water freezes and expands to break up rock—example pot holes
 Root Action
 Abrasion –when rocks collide –results in smaller, rounder smoother rocks—this happens in streams and in the desert
 Exfoliation—rocks “peel” when exposed to big temperature changes o Chemical Weathering dissolves the rock –example dissolving limestone rock to make a cave.
 Oxidation aka rusting—the iron in rocks reacts with oxygen resulting in an orange color on the surface
 Carbonation—aka carbonic acid—CO2 dissolves in rainwater slowly wearing away rocks—obvious in old tombstones
 Hydration—water dissolves some of the weaker minerals in a rock and the whole thing crumbles
Important points:
 Weaker aka less resistant rocks weather faster than more resistant rocks.
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Physical weathering happens in cold and moist climates –ex. Northeast
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Chemical weathering happens in warm and moist climates—ex. Southeast
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Weathering (both kinds) happens on the surface where the rock is exposed to the atmosphere and hydrosphere so the more surface area you have, the faster weathering can happen.
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Rocks broken down into many pieces have more total surface area.
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Soil is the most important product of weathering.
 Soil is made from weathered rock particles plus HUMUS—decomposed living things like plants, bacteria etc. Humus is found in the top layer which is black to dark brown and is essential to growing things.
 Residual soil is formed in place from the weathered bedrock beneath it.
 Transported soil was not formed in place but most likely brought in by glaciers.
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Most of the soil in NYS is transported.
Erosion—the transportation of weathered materials.
There are four ways to transport weathered materials—they are called the Four Agents of
Erosion:

Water—streams/rivers—abrasion results in pebbles. Streams carry particles by rolling along the bottom, in suspension and in solution.
Ocean waves remove sand in area and deposit it (ex, sand bars) in another area—follow the longshore current. Rock jetties are built perpendicular to the beach to trap sand.
Wind—in deserts—blasts sand into rocks—abrasion—arches and pitted, frosted appearance.
Sand dunes are moved around by the wind.
Ice—Glaciers—drag loose rocks over the landscape—which scrapes the land and existing bedrock—leave scratches in the rock. Also leaves behind glacial erratics—rocks brought in by the glacier which do not match the bedrock. Glacial deposits are sub-rounded and scratched and unsorted--also called “till” in general—a hill made of glacial deposits is called a “moraine”.
The Great Lakes and the Finger Lakes are examples of features formed by the last big glacier—
15,000 to 20,000 years ago.
Gravity—also a force—rocks falling off a cliff; also landslides. Rocks are jagged looking.
Deposition—transported rock materials are dropped off (to eventually become sedimentary rock). This happens when the transporting agent slows down or stops moving.
Deposition can be organized by size shape or density.
Deposition is either vertical or horizontal.
Horizontal Sorting happens when a stream enters a body of water (ocean or lake). It slows down and the larger particles get deposited first (near the shore) as the stream continues to slow down, the smaller, lighter particles get carried further from shore.
Vertical sorting –when all the particles fall to the bottom—the larger, heavier, rounder ones hit the bottom first (take less time) and the smaller, lighter and flatter particles hit the bottom last
(take more time)
WIND AND WATER DEPSOSITS ARE SORTED.
GRAVITY AND GLACIAL DEPOSITS ARE UNSORTED.
Streams have a youthful stage –steep slope, high velocity—white water/rapids, V-shaped valley, lots of erosion.

Streams have an Old Stage—flat, meandering, low velocity, cutoff meanders called oxbow lakes.
Deltas—deposit formed by river that empties into a large body of water.
Watershed or Drainage basin—the land drained by a river and its tributaries.
Tributary—a creek or stream that flows into a river.
The are four basic landscapes in NYS:
 Mountain
 Ridges
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Plateau
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Plain
Climate determines the type of landscape:
Dry Climate aka Arid (desert) climates produce sharp jagged features (think the West—places like Utah and Arizona)
Moist climate produces soft features—rounded hills—ex. NYS, Pennsylvania, Ireland