Magmatic Carbon Dioxide Emissions at Mammoth Mountain, California

By Christopher D. Farrar, John M. Neil, and James F. Howle

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations report 98-4217
Sacramento, California 1999

Abstract

Introduction

Background

Purpose and Scope

Acknowledgments

Location and Geologic History

Carbon Dioxide Emissions

Methods of Measurement and Investigation

Areas and Quantification of Emission

Trends

Potential Health Hazards

Source and Significance of Carbon Dioxide

Summary and Conclusions

References Cited

FIGURES

1,2. Maps showing:

1. Location of study area, Mammoth Mountain, California

2. Mammoth Mountain area: Selected topographic, geologic, and cultural features, and carbon dioxide sampling sites; and boundaries of tree-kill areas, sampling sites, carbon dioxide flux magnitudes, and carbon dioxide concentrations in soil on plate 1

3. Schematic cross sections showing configuration of permanent soil-gas sampler installations, and monitoring-well site HSL_1 of ground-water monitoring well and soil-gas samplers in the unsaturated zone, Mammoth Mountain,

4,5. Photographs showing:

4. Tree-kill areas near the base of the south face and the southwest side of Mammoth Mountain, and near the west shore of Horseshoe Lake, where carbon dioxide in the soil has killed nearly 100 percent of the trees in a 16-hectare area on plate 1

5. Tree well containing air with high CO₂ concentration on plate 1

6. Graph showing relation of oxygen and carbon dioxide derived from magmatic sources, Mammoth Mountain, California

TABLES

1. Soil gas carbon dioxide volumetric concentrations, Mammoth Mountain, California

2. Carbon dioxide flux (emission rate) at selected sites

3. Chemical analyses of water samples

4. Summary of carbon dioxide flux (emission rate) measurements

                               Multiply        By        To obtain
              
------------------------------------------------------------------                 

                         centimeter (cm)     0.3937      inch
                  cubic centimeter (cm3)      .06102     cubic inch
                                gram (g)      .03527     ounce (avoirdupois)
gram per square meter per day [(g/m2]/d)      .00345     ounce per square foot per day
                         millimeter (mm)     0.03937     inch
                               meter (m)     3.281       foot 
                          kilometer (km)     0.6214      mile 
                       square meter (m2)     0.0002471   acre
                            hectare (ha)     2.471       acre
                  square kilometer (km2)   247.1         acre
                 megagram per day (Mg/d)     1.102       ton per day 

VERTICAL DATUM

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)--a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

HORIZONTAL DATUM

In this report, the North American Datum of 1927 is used for Latitudes and Longitudes.

For additional information write to:
   District Chief
   U.S. Geological Survey
   Placer Hall, Suite 2012
   6000 J Street
   Sacramento, CA 95819-6129

Copies of this report (WRIR 98-4217) can be purchased from:
   U.S. Geological Survey
   Information Services
   Box 25286
   Federal Center
   Denver, CO 80225