Olympic Mountain Formation

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Olympic Mountain Formation
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Processes

• 1. Subduction of Juan de Fuca Plate
• 2. Accretionary Wedge of Mudstones, limestone,
  sandstones and conglomerates
• 3. Obduction of oceanic crust
• 4. Rising of sediments through oceanic crust (the
  pimple hypothesis)

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1. Subduction of Juan de Fuca Plate
2. Accretionary Wedge of Mudstones, limestone,
land sediments
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3. Obduction of oceanic crust

• Some Oceanic Crust Lifted OVER Accretionary
  Sediments

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4. Rising of sediments through oceanic crust (the
pimple hypothesis)
Accretionary Sediments are less Dense and rise
up through Basaltic Oceanic Crust
Oceanic Crust
Basaltic Crust erodes, now only located as a
donut around east and North edges
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Brandon, Roden-Tice Garver, 1998, Late Cenozoic
exhumatition of the Cascadia accretionary wedge
in the Olympic Mountains, NW Washington State
Bull. Geol. Soc. America, v. 110, p. 985-1009.
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Younger
Older
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