REPORT:
Geology of Mount Rainier National Park, Washington

Table of Contents

• Abstract

• Introduction
  • Acknowledgments
  • Scope of report

• Bedded rocks of early and middle Tertiary age
  • Rock nomenclature
  • Ohanapecosh Formation
    • Definition, distribution, and thickness
    • Formation boundaries
    • Lithology
      • Lava flow-mudflow complexes
      • Volcanic clastic rocks
      • Ash flows and rhyolites
    • Origin
    • Age
  • Stevens Ridge Formation
    • Definition, distribution, and thickness
    • Formation boundaries
    • Lithology
      • Ash flows
      • Volacnic clastic rocks
    • Contact between the Stevens Ridge and Ohanapecosh Formations
    • Origin
    • Age
  • Fifes Peak Formation
    • Definition
    • Formation boundaries
    • Distribution and thickness
    • Lithology
    • Origin
    • Age
    • Intrusive diabase and basalt

• Zeolitic metamorphism of the Ohanapecosh, Stevens Ridge, and Fifes Peak Formations
  • Zeolite facies
  • Zeolite facies metamorphism in Mount Rainier National Park

• Structures of the bedded rocks
  • Folds
  • Faults
  • Age relations of structural features

• Tatoosh pluton and related hypabyssal and volcanic rocks
  • Variability and complexity of the intrusive bodies
  • Rocks of the main Tatoosh pluton and associated stocks
    • Distribution
    • Petrographic and field variations
    • Alteration
    • Hornfels borders
  • Rocks of the hypabyssal complexes
    • Sill and dike swarms
    • Preferred zones of sill intrusion
    • Contemporaneity of sill complexes and pluton core
  • Rocks of the volcanic phase
    • Welded tuff and plug at The Palisades
    • Root zone of a plug in the western Sourdough Mountains
  • Relation of the Tatoosh pluton to nearby areas of Tertiary intrusive activity and volcanism
    • Snoqualmie Pass area
    • Naches Pass and Sand Creek areas
  • Evolution of the Tatoosh pluton: a summary
  • Age of the Tatoosh pluton

• Lava flows and mudflows of unknown age

• Mount Rainier volcano
  • Topography covered by the early eruptions
  • Nature of the early eruptions
  • Building of the main cone
  • Central plug and radial dikes
  • Eruptions at Echo Rock and Observation Rock
  • Destruction of the summit
  • Recent activity
    • Summit cone
    • Blankets of Recent pumice and ash
  • Age of Mount Rainier
  • Dissection of Mount Rainier
    • Glacial erosion
    • Rockfalls, mudflows, and slurry floods
    • Osceola mudflow
    • Summary
  • Petrography and mineralogy
  • Magma of Mount Rainier
  • Summary

• References cited

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