WEATHERING, SOIL, AND

MASS WASTING

DIFFERENCIATING EXTERNAL PROCESSES & INTERNAL PROCESSES

• External process- processes that occur at or near Earth’s surface and powered by the energy from the Sun

• Internal Process- processes that occur underneath the Earth’s surface and derives its energy from Earth’s interior

THREE EARTH’S EXTERNAL PROCESSES

1. Weathering

2. Mass Wasting

3. Erosion

WEATHERING- the physical breakdown & chemical

decomposition of rocks- part of the rock cycle- considered as a preparation for erosion- rocks are damaged physically and/or

chemically

AGENTS OF WEATHERING:• change of the environment

• Water

• air/wind

• human activities

• chemical substances

KINDS OF WEATHERING

1. Mechanical Weathering

2. Chemical Weathering

MECHANICAL WEATHERING- rock is broken to smaller pieces without

changing its chemical composition

- increases the amt. of surface available for chemical weathering

- results in smaller pieces from a single large one

4 PROCESSES OF MECHANICAL WEATHERING

a. Frost Wedging- caused by the freezing and thawing of water that seeps into cracks of rocks

b. Abrasion- caused by the rubbing and/or bouncing of rocks with each other

c. Exfoliation/Unloading- peeling away of large sheets of loosened materials in the rock

d. Biological Activities- caused by an organism’s activity such as plants, burrowing animals & humans

FROST WEDGING

EXFOLIATION

ABRASION

CHEMICAL WEATHERING - rock is broken down by chemical action

resulting in the change of the composition of the rock

AGENTS: 1. Oxygen 3. carbon dioxide2. Rainwater 4. acids produced by

decaying organisms

2 PROCESSES OF CHEMICAL WEATHERING

a. Oxidation- mineral is interacted chemically by oxygen

b. Hydration- mineral is interacted chemically by water

c. Carbonation- mineral is interacted chemically by carbon dioxide or carbonic acid

BAUXITE- COMBINATION OF OXYGEN, HYDROGEN & ALUMINUM

HEMATITE FORMED BY OXIDATION

EROSION- physical removal of the material- transporting of the rock from one place

to anotherAGENTS:1. Wind2. Water3. Ice

SHEET AND WIND EROSION

• Sheet erosion- soil is removed by thin sheets of water

• Wind erosion- caused by wind and only very significant during windy days or during a drought

RILLS AND GULLIES

• Rills- narrow incision of soil caused by overland flow

• Gully- landform created by running water which sharply eroded the land, typically on a hillside

GULLY

RILLS

MASS WASTING

- Movement of rock, regolith & soil under the direct influence of gravity

- The step that follows weathering

AGENTS OF MASS WASTING:1. Gravity- main controlling force2. Trigger- initiates downslope movements3. Water- heavy rains, snowmelt4. Over steepened Slopes5. Removal of Vegetation6. Natural Calamities

MOTION TYPES OF MASS WASTING1. fall- slopes which are too steep (ex.

Rockfall)2. Slides- materials remain fairly &

coherent & moves along a well defined surface (ex. Landslide)

3. Flow- moves downslope as a vicious FLUID (ex. Mudflow)

4. Slump- downward sliding of a mass

AVALANCHE L

ANDSLIDE

R O C K F A L L

THE END

BIBLOIGRAPHY:• Tarbuck, Edward and Lutgens, Frederick. Earth

Science: Basic Principles and Concepts, Pearson Education South Asia Pte Ltd. 23-25 First Lok Yang Road, Jurong Singapore

• http://www.regentsprep.org• http://www.google.com• http://images.google.com.ph/imghp?hl=en&t

ab=wi

THANKS FOR WATCHING!

By: Russel Christine CorcinoMSU-IIT IDS