USGS: Geological Survey Professional Paper 604: On Batholiths and Volcanoes—Intrusion and Eruption of Late Cenozoic Magmas in the Glacier Peak Area, North Cascades, Washington (Contents)

Geological Survey Professional Paper 604

On Batholiths and Volcanoes—Intrusion and Eruption of Late Cenozoic Magmas in the Glacier Peak Area, North Cascades, Washington

TABLE OF CONTENTS

Cover

Abstract

Introduction
Problem
Acknowledgments

Cloudy Pass batholith and associated rocks
   Geologic setting and age of intrusion at the level exposed
   Structure and contact relations
      General features
      Contact metamorphism
   Lithology
      General features
      Dark-colored phase
      Light-colored phase
      Alaskite dikes
   Inclusions and dikes of hornblende tonalite porphyry
      Intrusive breccia, dikes, and small masses
   Intrusion and differentiation

Early episode of volcanism: volcanic and volcaniclastic rocks of Gamma Ridge
   General character and age
      Petrology
      Widespread eruption of Gamma Ridge type rocks
      Origin and relation to the Cloudy Pass batholith

Late episode of volcanism: Glacier Peak volcano and associated rocks
   Previous work
   General features of the volcano
      Crater
      Disappointment Peak flow
      Stratigraphy of the lavas
      Age of the volcano
   Petrology of the Glacier Peak lavas
      Textural variations
      Mineralogy
         Quartz
         Plagioclase
         Pyroxene
         Hornblende
         Olivine
         Biotite
         Other minerals
         Inclusions
          Alteration
      Pyroclastic deposits and valley fills
          Fill of the Suiattle River valley
         Pumice deposits
         Fill of the White Chuck River valley
         Vitric tuff in the White Chuck River valley
         Other pyroclastic deposits
         Age and history
      Other volcanic rocks near Glacier Peak
         White Chuck Cinder Cone
         Indian Pass cinder cone
         Dishpan Gap cinder cone
         Flow of Lightning Creek
         Dikes
         Other centers of volcanism
      Hot springs
      Composition of Glacier Peak lavas and how it varies in time

Development of the Glacier Peak scene
   Position of the Cascade Crest
   Gamma Ridge eruptions and resultant drainage changes
   Glacier Peak eruptions and resultant drainage changes

Structures that guided the late Cenozoic magmas

References cited

Index (omitted from the online edition)

FRONTISPIECE.—Glacier Peak from northeast. Chocolate Glacier, far left; Dusty Glacier, middle left; Vista Glacier, right; and Ptarmigan Glacier, far right. Mount Rainier on left horizon. The gullied slopes of the foreground are underlain by pumice. Photograph by Austin Post.

ILLUSTRATIONS

COVER SKETCH. Glacier Peak from Image Lake. Outcrops of Cloudy Pass batholith on right

FRONTISPIECE. Photograph of Glacier Peak from northeast

PLATE

1. Geologic map and sections of the late Cenozoic igneous rocks of the Glacier Peak area, Washington (omitted from the online edition)

FIGURE

1. Location map
2. Sketch map of Cloudy Pass batholith and associated rocks
3. Sketch Showing distribution of thermal metamorphism around the Cloudy Pass pluton and nearby stocks
4. Ternary diagram of modal composition of the Cloudy Pass batholith and associated rocks

5—11. Photomicrographs:

5. Xenomorphic texture in light-colored phase of the Cloudy Pass pluton
6. Granophyric texture in light-colored phase of the Cloudy Pass pluton
7. Granophyric texture in light-colored phase of the Cloudy Pass pluton
8. Intergranular potassium feldspar and late-formed sodic plagioclase in light-colored phase of the Sitkum stock
9. Comblike granophyre intergrowth rimming and partially replacing twinned plagioclase crystal in Cloudy Pass pluton
10. Potassium feldspar partially replacing quartz in light-colored phase of the Cloudy Pass pluton
11. Most prevalent texture of light-colored phase of the Cloudy Pass pluton
12. Sketch map showing distribution of alsakite around the Cloudy Pass batholith
13. Photograph of hornblende tonalite porphyry
14. Photomicrograph of hornblende tonalite porphyry inclusion
15. Photomicrograph of olinozoisite filling in between plagioclase laths in hornblende tonalite porphyry inclusion
16. Photograph of intrusive dacite breccia
17. Photograph of intrusive breccia near the Cool stock
18. Photomicrograph of matrix of intrusive breccia
19. Variation diagram of the Cloudy Pass batholith and associated rocks
20. Ternary diagram showing normative position of alaskite and light-colored phases of the Cloudy Pass batholith
21. Sketch of view across the head of Dusty Creek to Gamma Ridge

22—25. Photomicrographs of Gamma Ridge rocks:

22. Volcanic tuff-breccia from lower Dusty Creek
23. Volcanic tuff-breccia
24. Monolithologic breccia
25. Altered porphyritic dacite
26. Schematic cross section of the Cloudy Pass batholith
27. Sketch of moraine underlying dacite flow of Glacier Peak
28. Photograph of southwest side of Glacier Peak showing thin flows of the summit cone truncated by dark-colored dacite of the Disappointment Peak dome
29. Sketch of ridge-capping flow of Gamma Ridge unconformably overlain by younger Glacier Peak ridge-capping flows
30. Ternary diagram showing predominant dacite composition of Glacier Peak lavas

31—40. Photomicrographs, dacite of Glacier Peak:

31. Vitrophyric texture
32. Hyalopilitic texture
33. Intersertal texture
34. Flow-banded pilotaxitic texture
35. Holocrystalline groundmass
36. Dacite of flow of figure 34 showing holocrystalline mesostasis of sodic feldspar and quartz with small biotite flakes
37. Resorbed quartz phenocrysts in dacite
38. Oscillatorily normally zoned plagioclase phenocrysts, individuals, and glomeroporphyritic clots in dacite
39. Magnetite pseudomorph of hornblende rimmed by pyroxene
40. Medium-grained inclusion with subophitic texture in dacite
41. Photomicrograph of diktytaxitic inclusion from dacite of Disappointment Peak dome
42. Photograph of Glacier Peak from the east showing apex of Suiattle fill between Chocolate Glacier and Dusty Creek
43. Photograph of Glacier Peak from the east showing Suiattle fill between Chocolate Creek, Dusty Creek, and Suiattle River
44. Sketch of interbeds of lava in the Suiattle fill
45. Radar image of Glacier Peak showing the smooth constructional surface of the Suiattle fill
46. Photograph of bedding in Suiattle fill
47. Graph showing optical properties of minerals and glass in pyroclastic ejecta and clasts of Suiattle and White Chuck fills

48—51. Photographs:

48. Mudflow deposits in White Chuck fill
49. Crossbedded sands and gravels in the White Chuck fill
50. White Chuck Cinder Cone from northwest
51. Stratified basaltic cinder deposits of Indian Pass cinder cone
52. Sketch map showing distribution of volcanic rocks, fresh andesitic and basaltic dikes, and probable volcanic conduits
53. Graph showing relationship between silica content and refractive index of glass beads fused from analyzed Cenozoic volcanic rocks
54. Graph showing silica content of extrusive rocks in the Glacier Peak area
55. Differentiation index diagram
56. Ternary diagram of normative compositions of Cenozoic igneous rocks of the Glacier Peak area
57. Sketches showing historical development of the Glacier Peak scene
58. Sketches showing development of the Suiattle fill
59. Photograph of forest buried in recent flood deposits along Suiattle River
60. Sketch map of North Cascades showing major intersecting structures in the area of the Cloudy Pass batholith and Glacier Peak volcano

TABLES

TABLE

1. Potassium-argon and lead-alpha radiometric age determinations of the Cloudy Pass batholith and its thermally metamorphosed host rock
2. Average modal composition of Cloudy Pass batholith and associated rocks
3. Composition of the Cloudy Pass batholith and associated rocks
4. Composition of eruptive rocks and dikes in the Glacier Peak area
5. Chemical analyses of hot springs in the Glacier Peak area
6. Preliminary isotopic composition of lead from rocks of Glacier Peak volcano and Cloudy Pass batholith

UNITED STATES DEPARTMENT OF THE INTERIOR
WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY
William T. Pecora, Director

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Last Updated: 28-Mar-2006