Geological Survey Professional Paper 296 Geology of Glacier National Park And the Flathead Region, Northwestern Montana

Cover

Abstract

Introduction

Location
Scope
Acknowledgments
Previous publications

Geography

Nomenclature of the ranges
Drainage
Relief
Climate
Transportation
Resources

General geology

Stratigraphy
   Outline of major points    Belt series (Precambrian)
      Classification
      Ravalli group
         Altyn limestone
         Appekunny argillite
         Grinnell argillite
      Piegan group
         Siyeh limestone
      Missoula group
         Correlations and divisions
         Main body
         Greenish calcareous argillite
         Purcell basalt
         Shepard formation
         Limestone
      Chemical composition of rocks of the Belt series
      Precambrian intrusive rocks
   Paleozoic strata
      Basis for divisions used
      Cambrian rocks
      Devonian rocks
      Upper Paleozoic rocks    Mesozoic rocks
      Jurassic rocks
      Cretaceous rocks
         Kootenai formation
         Colorado shale
         Montana group
         St. Mary River formation
         Undifferentiated Cretaceous deposits
   Cenozoic strata
      Old alluvium and associated deposits
      Terrace alluvium
      Glacial deposits
      Modern alluvium
      Landslide detritus
Structure
   Structural highlights
   Broad flexures or warps
      Precambrian structural features
      Paleozoic structural features
      Mesozoic structural features
   Mountain-building structural features
      Lewis overthrust
      Thrusts in the eastern disturbed zone
      Folds of the disturbed zone
      Structural features in the overthrust block
      Steep master faults
      Steep minor faults
   Interpretation of the structure
      General structural features
      Erosion thrust concept
      Dates of deformation
      The concept of a sole
      Depth of fracture
      Uplift
      Displacement
      Structural features above the thrust
      Present shape of the Lewis thrust
      Adjustments after the thrusting
      Summary of structural interpretation    Geomorphology
      General features of the geomorphology
      Effects of the early Tertiary uplift
      Concepts as to a summit peneplain
      Blackfoot erosional surface
      Post-Blackfoot erosional features
      Glacial features
      Recent erosional features

Literature cited

Index (omitted from the online edition)

PLATE

1. Reconnaissance geologic map of Glacier National Park, northwestern Montana. (omitted from the online edition)

2. Reconnaissance geologic map of the Flathead region, northwestern Montana. (omitted from the online edition)

3. Map of part of northwestern Montana, showing principal topographic features and outlines of quadrangles topographically surveyed in and near Glacier National Park and the Flathead region. (omitted from the online edition)

4. Hypothetical block diagrams illustrating steps in the development of the Lewis overthrust. (omitted from the online edition)

FIGURE

1. View northwest from Bennie Hill Lookout in the Heart Butte quadrangle, Flathead region

2. Altyn limestone in the lower slopes of Appekunny Mountain, northeast of Many Glacier Hotel, Glacier National Park

3. Air view northeast from above Gunsight Pass toward the valley of St. Mary River, with Lake Ellen Wilson in the foreground

4. Grinnell argillite on Broken Leg Mountain, Nyack quadrangle, Flathead region

5. Grinnell argillite on Broken Leg Mountain, Nyack quadrangle, Flathead region

6. Photomicrographs of rocks of the Belt series

7. Molar-tooth structure in Siyeh limestone in roadcut along Going-to-the-Sun Highway, Glacier National Park

8. Irregular banding in Siyeh limestone in roadcut along Going-to-the-Sun Highway, Glacier National Park

9. Photomicrographs of rocks of the Belt series and associated igneous rocks

10. Conophyton in roadcut in Siyeh limestone above the big switchback on Going-to-the-Sun Highway, Glacier National Park

11. Stromatolite on Tongue Mountain, Nyack quadrangle, Flathead region

12. Argillite of the Missoula group with sand-filled mud cracks, Upper Twin Creek, Marias Pass quadrangle, Flathead region

13. Cusped ripple marks in argillite of the Missoula group, head of Grouse Creek, Marias Pass quadrangle, Flathead region

14. Clay spalls in argillite of the Missoula group below Mount Bradley, Marias Pass quadrangle, Flathead region

15. Laminated argillite of the Missoula group with a small stromatolite, in railroad cut nearly opposite the mouth of Coal Creek Nyack quadrangle, Flathead region

16. View north from the head of Avalanche Basin, Glacier National Park

17. Closeup of Hannan limestone with chert layers, gorge of Gateway Creek, Heart Butte quadrangle, Flathead region

18. Contorted shale and limestone of the Ellis group on Badger Creek near the mouth of Red Poacher Creek, Marias Pass quadrangle, Flathead region

19. North side of the Middle Fork of the Flathead River showing exposure of beds of early Tertiary age

20. Sketch contours on the major surface of the Lewis overthrust near the eastern border of Glacier National Park

21. The trace of the Lewis overthrust as seen from Marias Pass looking north

22. View south from below Bennie Hill Lookout, Heart Butte quadrangle, Flathead region

23. Crooked Mountain, Heart Butte quadrangle, Flathead region

24. Irregular folds in limestone of Cambrian age south of Swift Reservoir, Heart Butte quadrangle, Flathead region

25. Contorted Grinnell argillite on the north wall of the cirque on the south slope of Mount Thompson, Glacier National Park

26. View northwest from Sperry Glacier showing part of the intensely folded rocks west of the major syncline

27. View southeast from near Fifty Mountain Camp, Glacier National Park showing the syncline that dominates the structure in the central part of the park

28. Overturned Grinnell argillite on McPartland Mountain, Glacier National Park, viewed from the northwest

29. Railroad cut along the Middle Fork of the Flathead River below the mouth of Coal Creek showing exposures of minor fractures in argillite of the Missoula group

30. View showing topography after the Blackfoot surface had formed in the area of Glacier National Park

31. View showing topography in the area of Glacier National Park at about the middle of Pleistocene time

32. View showing topography in Glacier National Park at the present time

33. Diagrammatic contour map of the Blackfoot surface in the region now occupied by Glacier National Park, with sections diagonally across the park

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A report on fieldwork and available data on the geology, structural, and geomorphic studies of the rocks, ranging from Precambrian to Recent in age, in two adjacent mountainous regions of Montana.

UNITED STATES DEPARTMENT OF THE INTERIOR
FRED A. SEATON, Secretary

GEOLOGICAL SURVEY
Thomas B. Nolan, Director

The U. S. Geological Survey Library has cataloged this publication as follows:
Ross, Clyde Polhemus, 1891—
Geology of Glacier National Park and the Flathead region, northwestern Montana. Washington, U. S. Govt. Print. Off., 1959.
iv, 125 p. illus., maps (part col.) diagrs., tables, 30 cm. (U. S. Geological Survey. Professional paper 296)
Three colored maps and colored diagr. in pocket. Bibliography: p. 118-121.
1. Glacier National Park. 2. Geology—Montana—Flathead region. (Series)
GE75.P9 no. 296     557.868     G S 58-174
___ _______ Copy 2.      QE133.R57

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