USGS Logo Geological Survey Professional Paper 554—D
Cenozoic Volcanic Rocks of the Devils Postpile Quadrangle, Eastern Sierra Nevada California

CONTENTS
Cover
Abstract
Introduction
Petrologic and chemical data
   Microscopic petrography
   Chemical data
   Classification
Andesite of Deadman Pass
Quartz latite of Two Teats
Andesite from Deadman—Glass Creeks area
Tuff of Reds Meadow
   Zonation in the tuff
      Lower flow unit
         Lower zone of no welding
         Lower zone of partial welding
         Zone of intense welding
         Upper zone of partial welding
      Upper flow unit
         Lower zone of partial welding
         Zone of intense welding
   Thickness and lateral extent
   Age, source, and correlations
Andesite of the Devils Postpile
Quartz latite of Mammoth Mountain
Andesite from Dry Creek area
Andesite of Pumice Butte
Olivine-bearing quartz latite
Basalt of the Red Cones
Rhyolite
Pumice
Thermal activity
Summary
References


ILLUSTRATIONS

FRONTISPIECE. Photograph showing well-developed columnar jointing in andesite at the Devils Postpile.

PLATE

1. Geologic map showing Cenozoic volcanic rocks of the Devils Postpile quadrangle, Sierra Nevada Calif (omitted from the online edition)

FIGURE

1. Index map of the Devils Postpile quadrangle

2. Variation diagram of the Mammoth Lakes volcanic suite showing classification according to the "alkali-lime index"

3. "Differentiation trend" diagram for the Mammoth Lakes volcanic suite

4. Silica—refractive-index diagram for volcanic rocks of the Mammoth Lakes area

5. Diagram showing range in percentage of silica of some of the mapped volcanic units as inferred from refractive indices of fused samples

6. Photograph of basal part of quartz latite of Two Teats on east side of San Joaquin Mountain

7, 8. Photomicrographs of tuff of Reds Meadow—
7. Lower flow unit
8. Upper flow unit

9. West-east section in vicinity of Rainbow Falls showing reconstructed surface of the tuff of Reds Meadow

10—13. Photographs of—
10. Polygonal joint pattern displayed by tops of columns in the Devils Postpile
11. Northernmost of the two Red Cones as viewed from the southern cone
12. Rhyolite dome south of Deadman Creek as seen from Deer Mountain
13. Upper surface of rhyolite dome south of Glass Creek showing typical irregular blocky surface

14. Vertical aerial photographs of Deer Mountain area, mounted as a stereopair

15. Photograph showing view of Inyo Craters from Deer Mountain



TABLES

TABLE

1. Ages of Cenozoic volcanic rocks of the Devils Postpile quadrangle
2. Petrographic summary of the volcanic rocks
3. Chemical analyses and norms of the volcanic rocks

UNITED STATES DEPARTMENT OF THE INTERIOR
STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY
William T. Pecora, Directory




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Last Updated: 18-Jan-2007