2. Have you ever wondered why scientists claim that Earth
before was so different from now with respect to its land
formation?
3. 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.
4. It is the breaking down of
rocks and other materials on
the earth surface.
5. 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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6. 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
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7. It is the process by which weathered
rock and soil particles are moved from
one place to another
8. Erosion (transport)
There are 5 main agents of erosion:
1. *Running Water*
2. Glaciers
3. Wind
4. Gravity Weathering has to happen before erosion. The rocks
have to be broken into smaller sediments before they
5. Man can be eroded away.
Wind Erosion
Glacier
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9. There is a pile of weathered material at
Mount Rushmore the bottom. It is slowly being eroded
down hill by gravity.
It will not be there forever!!
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10. The process by which sediments are
laid down in new locations.
11. 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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12. 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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13. 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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14. 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.
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