Surface Processes

Have you ever wondered why scientists claim that Earth before was so different from now with respect to its land formation?

Earth’s Changing Surfaces

Natural course of action wherein there is a changed plane or land due to different factors such as volcanic eruption, wind, running water, waves and etc.

WEATHERING

It is the breaking down of rocks and other materials on the earth surface.

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There are two primary types of weathering:Chemical and Physical

1. Physical Weathering – the breakdown of rocks and minerals into smaller pieces without a change in chemical composition.

Root/Plant Wedging/Action Ice/Frost Wedging/Action

Exfoliation and Abrasion are also types of physical weathering.

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2. Chemical Weathering – the breakdown of rocks and minerals into smaller pieces by chemical action. The rocks breaks down at the same time as it changes chemical composition. The end result is different from the original rock. There are 3 types of chemical weathering:

1. Oxidation – oxygen combines with the elements in the rock and it reacts. This the scientific name for rust.

2. Hydration – water can dissolve away many earth materials, including certain rocks.

3. Carbonation – carbon dioxide dissolves in water to form carbonic acid. This makes acid rain which chemically weathers (dissolves) rocks. Other acids also combine with water to make acid rain

EROSION

It is the process by which weathered rock and soil particles are moved from one place to another

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Erosion (transport)There are 5 main agents of erosion:1. *Running Water*2. Glaciers3. Wind4. Gravity 5. Man

Weathering has to happen before erosion. The rocks have to be broken into smaller sediments before they can be eroded away.

Wind Erosion

Glacier

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Mount Rushmore

There is a pile of weathered material at the bottom. It is slowly being eroded down hill by gravity.

It will not be there forever!!

DEPOSITION

The process by which sediments are laid down in new locations.

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Most deposition happens in standing/still bodies of water (oceans/lakes).

Deposition is caused by the slowing down (loss of kinetic energy) of the agent of erosion.

There are 3 factors that influence the rate of sediment deposition:1. Sediment size –

2. Sediment shape –

3. Sediment density -

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Graded Bedding/Vertical Sorting – a situation where larger particles settle on the bottom and smaller particles settle towards the top. This happens naturally when a fast moving river/stream meets a large standing body of water. This happens because the velocity of the water decreases very quickly. (A waterfall emptying into a lake)

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Alluvial Fan - a fan shaped deposit of sediments that forms when a stream/river flows out of a mountain on to flat, dry plains. These are not under water and are very visible. This only happens on the land. You can call it a “land delta”.

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Cross-Bedding – a situation where layers of sediments are deposited at angles to one another as a result of a change of direction of the erosional agent.

These are usually found in sand dunes, deltas, and alluvial fans.

PRESENTATION OF GROUP

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YMELYSSA C. PAULINESMARYROSE BONITASHANEN IMBOSUSMITA DOLORJOMAR PEDRAROJA