Gold and Other Minor Elements Associated with the Hot Springs and Geysers of Yellowstone National Park, Wyoming, Supplemented with Data from Steamboat Springs, Nevada U.S. GEOLOGICAL SURVEY BULLETIN 2001 AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Survey publications released prior to the current year are listed in the most recent annual "Price and Availability List" Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. 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FOURNIER U.S. GEOLOGICAL SURVEY BULLETIN 2001 U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Text and illustrations edited by George A. Havach UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1992 For sale by the Books and Open-File Reports Section U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225 Library of Congress Cataloging-in-Publication Data White, Donald Edward, 1914- Gold and other minor elements associated with the hot springs and geysers of Yellowstone National Park, Wyoming, supplemented with data from Steamboat Springs, Nevada I by Donald E. White, Chris Heropoulos, and R.O. Fournier. p. em. - (U.S. Geological Survey bulletin ; 2001) Includes bibliographical references. 1. Gold ores-Yellowstone National park. 2. Gold ores-Nevada­ Washoe County. 3. Hydrothermal deposits-Yellowstone National Park. 4. Hydrothermal deposits-Nevada-Washoe County. I. Heropoulos, Chris. II. Fournier, R.O., Ill. Title. IV. Title: Steamboat Springs, Nevada. V. Series. QE75B9 no. 2001 (QE390.2.G65) 557.3 s-dc20 91-29371 [553.4 1110978752] CIP CONTENTS Abstract 1 Introduction 1 Comparison of analytical methods for gold 2 Diagenesis of the hydrothermal silica minerals 2 Gold and associated elements deposited from hot-spring systems at Yellowstone National Park 4 Opaline hot-spring sinter S Chalcedonic sinter deposits 7 Gold and associated elements in miscellaneous spring deposits 7 Gold and associated elements in miscellaneous materials collected at shallow depths 8 Gold and associated elements in hydrothermal eruption craters 8 Gold and associated elements in core from drill holes Y-12 and Y-13, Norris and Lower Geyser Basins, Yellowstone National Park 9 Gold in samples from Steamboat Springs, Nevada 10 Gold in material precipitated from hot springs 10 Gold and associated elements deposited in three drill holes at Steamboat Springs, Nevada 11 Conclusions, interpretations, and speculations 13 References cited 18 FIGURES 1. Index map of Yellowstone National Park, Wyo., showing locations of analyzed samples by thermal area 3 2. Plot of solubilities of common silica minerals in water as a function of temperature S 3. Geologic sketch map of Steamboat Springs thermal area, Nev. 14 4. Plot of antimony versus gold contents in samples from Yellowstone National Park and Steamboat Springs 16 5. Plot of arsenic versus gold contents in samples from Yellowstone National Park and Steamboat Springs 17 6. Log-log plot of thallium versus gold contents in samples from Yellowstone National Park and Steamboat Springs 18 TABLES 1. Reported Au contents in some hot-spring deposits of Yellowstone National Park, Wyoming, and Steamboat Springs, Nevada 4 2-9. Contents of gold and associated elements in: 2. Opaline sinters of Yellowstone National Park, Wyoming 6 3. Chalcedonic sinter of Yellowstone National Park, Wyoming 8 4. Miscellaneous spring deposits of Yellowstone National Park, Wyoming 9 5. Miscellaneous near-surface materials from well-established depths, Yellowstone National Park, Wyoming 10 6. Samples from hydrothermal eruption craters of Yellowstone National Park, Wyoming 11 7. Core from drill holes Y-12 and Y-13, Norris Geyser Basin and Lower Geyser Basin, Yellowstone National Park, Wyoming 12 8. Samples from three drill holes, Steamboat Springs, Nevada, for comparison with Yellowstone National-Park, Wyoming 13 9. Samples from Yellowstone National Park, Wyoming, that are relatively gold rich 15 Contents Ill Gold and Other Minor Elements Associated with the Hot Springs and Geysers of Yellowstone National Park, Wyoming, Supplemented with Data from Steamboat Springs, Nevada By Donald E. White, Chris Heropoulos, and R.O. Fournier Abstract of greater dilution by a more abundant water supply at Yellowstone. A commonly held theory of the origin of epithermal ore deposits relates Au, Ag, Hg, As, Sb, Tl, and other "volatile" elements to "fossil" hot-spring systems that trans­ INTRODUCTION ported and deposited these metallic elements close to the ground surface existing at the time. In the early 1970's, an emission-spectrographic method using short-wavelength ra­ A commonly held theory of the origin of epither­ diation (SWR) was developed for use in the analysis of mal ore deposits relates Au, Ag, Hg, As, Sb, and other these "volatile" elements. This method was applied to 125 "volatile" elements to "fossil" hot-spring systems that samples of rock and hot-spring chemical precipitates from transported and deposited these metallic elements close Yellowstone National Park and 43 samples from Steamboat to the ground surface existing at the time. A second Springs, Nev. The results of those analyses are presented group of epithermal deposits, consisting mainly of the here. Recently, other, more sensitive methods for the base metals Cu, Pb, Zn, and Ag, is generally thought to analyses of gold and volatile elements have been devel­ form at greater depth within hydrothermal systems. oped and (or) become less expensive, but these methods Base-metal deposits are not considered in this report, al­ generally have not yet been applied to Yellowstone though zinc is reported here as a trace element. Silver is samples. commonly present in both groups and generally becomes A few samples from Yellowstone National Park and Steamboat Springs were analyzed by neutron-activation (NA) more abundant downward where the base metals under­ and SWR methods, as well as by fire assay. In general, the lie "volatile element" deposits. results from the SWR method agree more closely with those Geologists and geochemists familiar with low­ from the fire-assay than the NA method. Present findings re­ grade, dispersed, epithermal gold deposits have applied veal significant gold contents (more than 0.1 ppm) in only a various names to them, including "bulk minable," "sedi­ few samples from Yellowstone, but the general principles re­ ment hosted," and "invisible gold." These types of de­ lating Yellowstone's hot-spring and geyser activity to gold posits became the focus of exploration programs in the transport and deposition are of considerable interest as a 1960's, when the value of gold increased dramatically. guide to how gold deposits may have formed elsewhere. Gold is now routinely analyzed at levels above 1 part Concentrations of Sb, As, Hg, B, Tl, and Zn vary widely per billion (ppb) by neutron-activation (NA), and of 1-2 with respect to Au and each other in the Yellowstone and Steamboat Springs samples.