Principles of Geography GEO 100

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Principles of GeographyGEO 100

• Chapter 3 - Physical Geography
• St. Charles Community College
• Ellen Wilson

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Geologic Time
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Continental Placement

• Is the distribution of continental masses random?

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Layers of the Earth
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Layers of the Earth
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Layer Densities

• Crust
• Continental
• Oceanic
• Mantle
• Lithosphere
• Asthenosphere
• Mesosphere

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Plate Tectonic Theory

• Egg Shell

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Plate Tectonic Theory

• Conveyor Belts
• Website of plate movement

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Plate Theory Background

• European map making 1600s
• Alfred Wegener
• Continental Drift

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Pieces of a Puzzle
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Ancient movements
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Boundaries
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Convergent C-C
Mt. Everest 29,035
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Convergent- O-O
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Convergent O-C
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Boundaries - Divergent
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Ridges and Trenches
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Boundaries - Transform
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Earthquakes
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Distribution of Earthquakes Random?
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Evidence

• Harry Hess
• Sea Floor Spreading
• Divergent Zones
• Trenches
• Convergent Zones

• Core Samples
• Animation web site

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Evidence

• Paleomagnetism
• Vine and Matthews

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Magnetic Striping

• Animation

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Explanation for movement

• Convection of Asthenosphere

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Exceptions to Plate Edge Activity

• Accreted Terranes

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Exceptions (cont)

• Mantle Plumes Hot Spots

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Global Hot Spots
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Geomorphology on Continents

• Change of landforms
• Diastrophism - Constructive
• Denudation - Destructive

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Rock Categories - Igneous
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Sedimentary
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Sedimentary (cont)
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Metamorphic
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Diastrophism - Create

• Isostasy
• Broad Warping
• Buoyancy

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• Broad Warping (cont)

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Folding
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• Folding (cont)

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Faulting
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• Faulting (cont)

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Volcanic Formations - Extrusive

• Landforms created from lava
• Cone Shape
• Silica cools
• Low Silica stays hot and liquid
• High Silica cools down and thickens

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Cone Shape - Shield

• Low silica low explosion
• Lava flows expand width

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Shield Volcano - Hawaii
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Cone Shape-Composite

• High silica high explosion
• Removal of top creates conic shape

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Composite Volcano Mt. Fuji
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Cone Shape - Caldera

• Mt. St. Helens webcam

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Crater Lake
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Krakatau

• Krakatau Web Site
• NPR - Krakatau

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Volcanic Formation - Intrusive
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Batholith
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Chimney and Dikes
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Sill
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Denudation Destroy
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Weathering - Mechanical

• Frost/Salt Shattering/Wedging

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Weathering - Chemical
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Gravity Transfer/Mass Wasting
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Gravity Transfer - Fall
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Gravity Transfer- Landslide
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Gravity TransferCreep
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Erosion - Fluvial ProcessesRivers as Cleaners

• Load
• Quantity
• Competence
• Size particle moved
• Volume Velocity
• Speed increase 6th power Size
• 2X2X2X2X2X264

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Competence (cont)

• Works both ways
• Erosion
• Deposition

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Competence-Deposition

• Deltas

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Competence - Deposition

• Alluvial Fans

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Rivers as Flatteners

• Meandering
• horizontal motion
• Begins at Base Level

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Meandering (cont)
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Meandering (cont)

• V-shaped Valleys

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Meandering (cont)

• U-Shaped Valleys

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Meandering (cont)

• Oxbow Lakes

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Oxbow Lake (cont.)
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Create-Destroy-Repeat

• Diastrophism is concurrent with denudation

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Erosion/Deposition

• Wind Wave Action

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Erosion/Deposition

• Glaciers

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• Questions??