Geology Underfoot in Yosemite National Park

by Allen F Glazner, Greg M Stock

Overview

Few places in the nation rival Yosemite National Park for vertigo-inducing cliffs, plunging waterfalls, and stunning panoramic views of granite peaks. Many of the features that visitors find most tantalizing about Yosemite have unique and compelling geologic stories tales that continue to unfold today in vivid, often destructive ways. While visiting more than twenty-seven amazing sites, you ll discover why many of Yosemite s domes shed rock shells like onion layers, what happens when a volcano erupts under a glacial lake, and why rocks seem to be almost continually tumbling from the region s cliffs. With a multitude of colorful photos and illustrations, and prose tooled for the lay reader, Geology Underfoot in Yosemite National Park will help you read the landscape the way a geologist does.
The Geology Underfoot series encourages you to get out of your car for an up-close look at rocks and landforms. These books inform and enlighten, no matter how much or how little geology you already know. What s more, they re simply good reading, on-site or at home.

Product Details

ISBN-13:	9780878425686
Publisher:	Mountain Press
Publication date:	05/28/2010
Series:	Geology Underfoot
Pages:	299
Sales rank:	322,307
Product dimensions:	6.00(w) x 8.90(h) x 0.80(d)

About the Author

Allen F. Glazner is the Kenan Distinguished Professor of Geological Sciences at the University of North Carolina at Chapel Hill. A native Californian, he holds a PhD from the University of California at Los Angeles and has done research in the Sierra Nevada and Mojave Desert from his undergraduate days at Pomona College.


Greg M. Stock was born and raised in the Sierra Nevada just north of Yosemite. He has a bachelor s degree in geology from Humboldt State University and a PhD in earth science from the University of California at Santa Cruz. Greg is Yosemite National Park s first-ever park geologist.

Table of Contents

Preface vii

Introduction 1

Yosemite's Geologic Backdrop 1

How Glaciers Work and How They Shaped Yosemite 10

What is a Glacier? 11

How Glaciers Erode 16

Glacial Modification of Landscapes 18

What Glaciers Leave Behind 22

History of Glaciers in Yosemite 24

Modern Glaciers 29

Rivers and Streams in Yosemite 30

Geologic Study of Yosemite 36

1 Bones of the Earth: Granite, Granodiorite, and the Bedrock of Yosemite 41

2 Vertical Exposure: The Geology of Yosemite Climbing 57

3 Pushed Off a Cliff: The Origin of Yosemite Falls 71

4 Giant Steps: Vernal and Nevada Falls 77

5 Free-Falling Granite: The 1996 Happy Isles Rockfall and its Unusual Air Blast 85

6 That's the Way the Cookie Crumbles: The 1982 Cookie Cliff Rockslide 95

7 The Walls Came Tumbling Down: Earthquakes and Rock Avalanches in Yosemite Valley 103

8 How Water Sculpts Yosemite: The Flood of 1997 111

9 A Natural Dam Across Yosemite Valley: The El Capitan Moraine 121

10 Cracks in the Earth: The Fissures of Taft Point 131

11 Half a Dome is Better Than None: Sentinel Dome and Half Dome 139

12 The Earth as an Onion: Exfoliation Joints 147

13 The Ice Went Thataway!: The Shaping of Pothole Dome 155

14 Exotic Erratics: Glacially Transported Boulders at Olmsted Point 165

15 Why are there Trees Poking Out of Tenaya Lake? The Great Medieval Megadrought 171

16 Soda Springs: That Fizzy Taste Carries a Geochemical Surprise 181

17 Runaway Rocks: Metamorphic Rocks at May Lake 187

18 Root of an Ancient Volcano: Little Devils Postpile 195

19 Tombstone Rocks, Slate, and Greenstone: Rocks of the Western Approaches 205

20 Inverted Landscape: The Stanislaus Table Mountain Lava Flow 217

21 Eocene Erosion: Ancient, Weathered Landscapes of the Sierra Nevada 225

22 An Ancient, Ice-Bound Sea: Mono Lake and Ancestral Lake Russell 235

23 An Underwater Volcano: Mono Lake's Black Point 247

24 Evidence of the Ice Ages: Glacial Deposits in and Around Lee Vining Canyon 255

25 Dreams of Silver: The Mines of Bennettville and Dana Village 267

Glossary 274

Sources of More Information 282

Index 289