The breakdown of rock and Earth materials at the surface as a result of physical or chemical processes Occurs due to the exposure to air, water and the actions of organisms

Breakdown of rock into smaller pieces without chemical change Examples: frost action, plant root growth, exfoliation, abrupt temperature change

Ice Wedging Expansion of water in cracks when water freezes, causes cracks to grow larger Animation

Frost Action (Ice Wedging) Alternating freezing and thawing of water For example, the numerous potholes which form every winter!

Root Action (Plant Action) roots work their way into rock and break it apart

Abrasion physical weathering caused by the grinding of rock particles against rock Mushroom Rock, CA

Animal Action - insects, mammals, lizards, etc. allow air and water to reach buried rocks when they dig up the surface

Temperature Change – alternating heating and cooling of rocks may result in expansion and contraction causing the rock to fracture and break apart

the breakdown of rock through a change in mineral or chemical composition acids, water (hydrolysis), & air (oxidation) affects surfaces of rocks enhanced by acid rain example = rust

Chemical Weathering enhanced by acid rain Did the artists intend their work to look like this?

Chemical Weathering Chemical Weathering affects the surface of rocks. An increase in surface area from physical weathering results in an increase in the rate of chemical weathering notice the weathering rind around this rock

1. – weathering affects exposed surfaces 2. – smaller particles have greater surface areas 3. – a mineral has specific chemical and physical properties, which control how it will weather 4. – temperature and water greatly control the rate of weathering Exposure Particle Size Mineral Composition Climate

When rocks are crushed, their surface area increases This will cause them to weather faster chemically!!

EgyptManhattan same age Why do they look so different? Warm, moist climates have the quickest chemical weathering. Dry climates have virtually no chemical weathering.

Originates from the sediments created by weathering (usually physical) Mature through the addition of organic matter and liquid water. The water continues the process of chemical weathering and helps provide nutrients for the living environment. As sediments mature, they form a series of layers called soil horizons.

– Residual Soil – formed by the weathering of the bedrock underneath it. – Transported Soil – formed by material that is not the same as the native bedrock – Most soils in NY are Transported Soils due to extensive glaciation in the recent geologic history.

Which soil horizon contains the greatest amount of organic matter and biological activity? O, A, B, or C? O A B C

What type of soil cover is more common in NYS? Residual or Transported Soil Maximum extent of glaciation

Transporting Agents Include: – Running Water – Coastal Processes – Glaciers – Wind – Gravity Gravity is the driving force behind all erosional systems! How do you know?

Running water is the primary agent of erosion on Earth. ______________ - a stream’s ability to move particles of different size. ______________ - the average speed of the water in a stream (cm/s). The higher the velocity, the greater the erosion. ________________ - the volume of water in a stream (cubic feet/sec or cubic meter/sec). Higher discharge means higher erosion. Stream Velocity Stream Discharge Carrying Power

Each of the 3 streams above contain the same volume of water. Assuming equal gradients, stream C would have the greatest stream velocity due to its semi-circular Stream Channel which allows for the least amount of friction. A B C

The higher the velocity… the larger the particle size that a stream can “carry” Cobbles Boulders

Streams Flow DOWNHILL due to GRAVITY

Let’s Examine a Meander Bend in more detail Where is the greatest erosion? Where is the greatest deposition? Why? C D Velocity is greatest on the outside of meander bends!

This is the outside part of a meander, which means that there is more erosion happening on this side. Deposition is taking place on the other side!

Choose the correct rock… Which one of the following represents a particle that has been transported by running water (streams/rivers)?

Waves and surface ocean currents are driven by the. As a wave approaches shallow water along a shoreline, friction causes the bottom of the wave to slow down, thereby causing the top of the wave to curl forward and eventually collapse (break). wind

Erosion Deposition

Longshore Drift - the movement of sediment parallel to the shore as waves strike the shoreline at an angle.

Glacial Ice Sheets - enormous sheets of ice that move due to the pull of gravity. Some of the material moved is bulldozed in front of the massive ice sheet but most hitches a ride trapped in the midst of the glacier itself.

Glaciers carve U-Shaped Valley’s (as opposed to a stream’s V-Shape)

Rock is dragged over and scratches bedrock due to great pressure from the overlying glacier Rock Abrasion between the ground and the rocks and sediment trapped in glacial ice removes the soil, and leaves parallel scratches and grooves called glacial striations that can give us an idea of the direction of ice flow.

Glacial Landforms Glacier National Park, Montana

A B C D E

Glacial deposits and landscape features Long Island ?

Wind Wind is a particularly important agent of erosion in arid climates. You can tell the general direction of the wind by looking at the shape of the deposit.

Wind

Wind Formed Landforms Mushroom Rocks Protecting the utility pole from sandblasting Formation of a ventifact Wind erosion can lower landscapes

Mass Wasting