10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
ISOSTASY
Force
Process
Then what is ISOSTASY?
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
Story of Isostasy!!
Bouguer Correction
Deflection of Vertical in India
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
Airy’s Theory
Varying crustal thickness laterally
CRITICS OF AIRY’S THEORY
•Assumption of thin crust
•Crust was less dense than underlying – lava
•Not in accordance to contraction theory of
earth
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
DEPTH OF COMPENSATION
Pratt’s Theory
Varying crustal density laterally
PRATT
AIRY
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
Vertical movement of land
Dutton’s Theory
Coi ed ter
I“O“TA“Y
Equal masses must underlie equal surface
areas
Elevated mass -> Low Density
Depressed mass -> High Density
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
Heiskenen’s Theory
AIRY + PRATT
Higher density -> Shorter Columns
Hayford and Bowie Theory
Similar to Pratt
Inverse relation between height of
column and density
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10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
Joly’s Theory
Contradicted Hayford and Bowie
Zone of Compensation (10-mile thick)
Holmes & Holmes Theory
Supported Airy
High columns can stand - Have lighter
material below them for greater depth
Equal weight along level of equal pressure
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7
10/13/2015
These slides accompany the YouTube Video Tutorial: https://www.youtube.com/watch?v=Wn5R8IBDj0s
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