Geodynamics
Kinematics of plate tectonics
Lecture 2.3 - Transform plate boundaries
and the Wilson cycle
Lecturer: David Whipp
[email protected]
Geodynamics
www.helsinki.fi/yliopisto
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Goals of this lecture
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Present transform plate boundaries
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Review the Wilson cycle and its relationship to all three plate
boundary types
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Plate boundaries
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Three different principal types of plate boundaries
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Divergent (accreting)
Convergent (subduction)
Transform
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Plate boundaries - Transform
Map view
Cross sectional view
Fig. 1.12, Turcotte and Schubert, 2014
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This is the most common form of transform fault, between two spreading
ridge segments
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Plate boundaries - Transform
Map view
Cross sectional view
Fig. 1.12, Turcotte and Schubert, 2014
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This is the most common form of transform fault, between two spreading
ridge segments - What is the slip rate on the transform fault above?
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Plate boundaries - Transform
Wilson, 1965
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Six types of dextral transform fault predicted by Wilson
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The Wilson cycle
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In 1966, Wilson proposed the
opening and closing of ocean basins
is cyclic
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A simple case is outlined here, with
initial rifting of a continent and
formation of a spreading center
Fig. 1.42, Turcotte and Schubert, 2014
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The Wilson cycle
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Continued extension leads to
formation of an ocean basin
Fig. 1.42, Turcotte and Schubert, 2014
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The Wilson cycle
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As the seafloor ages and density
increases and eventually the margin
founders, initiating subduction
Fig. 1.42, Turcotte and Schubert, 2014
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The Wilson cycle
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The ridge may eventually be
subducted, drawing the two
continental margins together into
eventual collision
Fig. 1.42, Turcotte and Schubert, 2014
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The Wilson cycle
Fig. 1.42, Turcotte and Schubert, 2014
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Test your might
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You can find a short quiz about this lecture at https://elomake.helsinki.fi/lomakkeet/63026/lomake.html
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Please take the quiz to help me know what you have learned
Your answers are anonymous and will not count in your
course grade
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