Download Unit 4: Deformation of the Crust

Unit 4: Deformation of the
Crust
Mr. Ross Brown
Brooklyn School for Law and Technology
In what ways is the crust deformed?
• 31 October 2016
• Do now: This question may require the use of the Earth Science
Reference Tables. In the diagram below which shows a portion
of the Earth's crust, what is the relative age of the igneous
rock?
a) It is older than the limestone
but younger than the shale.
b) It is younger than the limestone
but older than the shale.
c) It is older than both the limestone
and the shale.
d) It is younger than both the limestone
and the shale.
In this unit we will learn about:
• How isostatic adjustment causes stress on the crust
• How this stress leads to faulting and folding
• How mountains formed as a result of plate tectonics and other Earth
activity
How does the weight of the crust shape the
Earth?
• 1 November 2016
• Do now: This question may require the use of the Earth Science
Reference Tables. This block diagram shows a section of the
Earth's crust. The rock layers have not been overturned. I, II, III,
IV, and V are locations on the Earth's surface. The deformed
rock strata in the block diagram above are primarily the result
of:
a) Folding
b) Faulting
c) Ground water
d) Volcanism
How does the weight of the crust shape the
Earth?
• We said the crust ‘rides’ on the mantle
• Heavier crust (mountains) sink down
• Lighter crust rises
• Crust presses down, mantle presses up
• The balance is called isostasy
• Isostatic adjustments lead to bending and deformation
Isostatic Adjustments
Homework #3 (only 3???)
• 1 November 2016
• Define and contrast geologic stress and geologic strain
• Name and describe the 3 main types of geological stress