Geological Survey Bulletin 1292 The Geologic Story of Mount Rainier

Cover

Introduction

The Changing Landscape of 12-60 Million Years Ago

Thumbnail Biography of Mount Rainier

Results of Recent Eruptions

Why Glaciers?

Work Habits of Glaciers

Yesterday's Glaciers

Landslides and Mudflows — Past, Present, and Future

The Volcano's Future?

Further Reading in Geology

FIGURES

Frontispiece. Eunice Lake, northwest of Mount Rainier

1. Outcrop of sandstone and shale in the Pugest Sound

2. Outcrop of welded tuff in the Stevens Ridge Formation

3. Granodiorite looks like granite

4. Geological cross section of Mount Rainier

5. Columns of andesite at the end of an old lava flow

6. Layers of pumice on the floor of a cirque

7. Breadcrust bomb enclosed in a mudflow depost

8. Generalized distribution of some pumice layers

9. Pumice layer C, which consists of light-brown fragments

10. The recent lava cone lies in a depression

11. Two ice streams meet to form Cowlitz Glacier

12. Glacier-smoothed and grooved rock

13. A lake lies behind an end moraine of Flett Glacier

14. Recessional moraines on the valley floor of Fryingpan Creek

15. Extent of glaciers between 15,000 and 25,000 years ago

16. Lateral moraine at Ricksecker Point

17. Rock-glacier deposit at The Palisades

18. Hummocky end moraine in front of Emmons Glacier

19. Avalanche deposits in the White River Valley

20. The northeast flank of Mount Rainier

21. An old lava flow which forms Rampart Ridge

TABLES

1 Characteristics, sources, and ages of pumice layers, Mount Rainier National Park

2 Summary of important geologic events in the history of Mount Rainier National Park

Eunice Lake, northwest of Mount Rainier. The lake lies in a small bedrock basin that was scoured out by a glacier between about 15,000 and 20,000 years ago. The rounded green slopes at the far edge of the lake are underlain by rock that has been smoothed and grooved by glacial ice. This side of Mount Rainier rises to Liberty Cap, which hides the true summit of the volcano.