1_README.TXT

U.S. GEOLOGICAL SURVEY
OPEN-FILE REPORT 98-338



CONTRIBUTIONS TO THE GOLD METALLOGENY
OF NORTHERN NEVADA



By

Richard M. Tosdal(1), editor



1998









U.S. DEPARTMENT OF THE INTERIOR
BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY
Charles G. Groat, Director


This report is preliminary and has not been reviewed for 
conformity with U.S. Geological Survey editorial standards or 
with the North American Stratigraphic Code. Any use of trade, 
firm, or product names is for descriptive purposes only and 
does not imply endorsement by the U.S. Government.

For sale by U.S. Geological Survey, Information Services, 
ESIC Open-File Reports, PO Box 25286, Denver, CO 80225 
(888) ASK-USGS

(1)-U.S. Geological Survey, Menlo Park


QUICK START

For those already familiar with Adobe Acrobat Reader and who 
have Version 3.0 or higher on their computer, go directly to 
the file OF98_338.PDF.  This file consists for the CD-ROM 
title and opening pages and is the starting or "navigation" 
point for this report with links to the chapters.

INTRODUCTION TO REPORT

Nevada is one of the Earth's premier gold producing regions, 
accounting for approximately 64 percent of the U.S and 9 
percent of the world total.  The impact of these mines on 
nearby local economies and on our national balance of 
payments is profound, and will continue well into the next 
century.  Of principal importance in this region are giant 
sedimentary-rock-hosted (Carlin-type) deposits.  These are 
some of the world's largest deposits, but yet are poorly 
understood.  Other sedimentary-rock hosted deposits in the 
region, the distal-disseminated Ag-Au type, are genetically 
related to shallow plutonic complexes.  Hot-spring gold-
silver systems associated with Tertiary volcanic rocks 
represent a third type of precious metal deposit in northern 
Nevada.  These deposits, despite being generally smaller than 
sedimentary-rock-hosted gold deposits, are also important 
gold-silver resources.  Aspects about the geologic and 
metallogenic setting of gold-silver deposits in northern 
Nevada are addressed in the twenty-two chapters that compose 
this volume.  The volume is organized along four themes: (1) 
crustal structure; (2) Carlin-type deposits; (3) pluton-
related gold-silver deposits near Battle Mountain; and (4) 
hot-spring gold-silver deposits.  This Open-File Report, the 
result of ongoing geologic and mineral-resource 
investigations, provides a basis for mineral exploration, for 
land-use planning decisions, and for environmental questions 
in northern Nevada. 

ABOUT THE COVER

(Top) Raised relief map of northern Nevada showing the major 
belts of ore deposits, the Battle Mountain-Eureka mineral 
belt and the Carlin trend, in relation to the mid-Miocene 
northern Nevada rift along which hot-spring Au-Ag deposits 
are developed.  Also shown are the interpreted distribution 
of basement types, based on Pb and Sr isotopic mapping, and 
the transition from intact Proterozoic and Archean crust on 
the east across thinned continental into regions floored by 
"oceanic crust" on the west.  (Bottom) Photograph of gold-
rich arsenian pyrite rims on older pyrite and arsenopyrite 
from the Getchell deposit.  Arsenian pyrite-containing gold 
is typical of sedimentary-rock-hosted or Carlin-type 
deposits, the largest gold deposits, in Nevada.

DISCLAIMERS

This Compact Disc-Read Only Memory (CD-ROM) publication was 
prepared by an agency of the United States Government. 
Neither the United States Government nor any agency thereof, 
nor any of their employees, makes any warranty, expressed or 
implied, or assumes any legal liability or responsibility for 
the accuracy, completeness, or usefulness of any information, 
apparatus, product, or process disclosed in this report, or 
represents that its use would not infringe privately owned 
rights. Reference therein to any specific commercial product, 
process, or service by trade name, trademark, manufacturer, 
or otherwise does not necessarily constitute or imply its 
endorsement, recommendation, or favoring by the United States 
Government or any agency thereof.

Although all data and software published on this CD-ROM have 
been used by the USGS, no warranty, expressed or implied, is 
made by the USGS as to the accuracy of the data and related 
materials and (or) the functioning of the software. The act 
of distribution shall not constitute any such warranty, and 
no responsibility is assumed by the USGS in the use of this 
data, software, or related materials.

SYSTEM REQUIREMENTS

The data and text on this CD-ROM require either a Macintosh 
or compatible computer or an IBM or compatible personal 
computer equipped with a CD-ROM drive.  The Macintosh should 
have a 68020 or higher processor (PowerPC recommended), 8 
megabytes RAM (16 MB recommended), Apple System Software 
version 7.0 or later (7.1.2 or later recommended), and a 13-
inch color monitor that can display 256 colors.  The PC 
should have a 386 or higher processor (Pentium recommended), 
Microsoft Windows 3.1 or higher (Windows 95, 98, or NT 
recommended), 8 megabytes RAM (16 MB recommended), and a VGA 
color monitor that can display 256 colors.  Both platforms 
require Adobe Acrobat Reader 3.0 or higher (3.01 included on 
this disc) or other software that can translate PDF files.  
If you are using Acrobat Reader 2.1 or lower, you will need 
to upgrade.

This CD-ROM was produced in accordance with the ISO 9660 and 
Macintosh HFS standards. All ASCII and TXT files can be 
accessed from DOS, Macintosh, and Unix platforms, the display 
software packages provided are designed for use under a DOS-
based, Windows-based, or Macintosh system, as appropriate.

TO GET STARTED: 

On a Macintosh, double-click on the CD-ROM icon and double-
click on the file 1_README.TXT.  On a PC system with Windows, 
open Notepad or a word-processing application, change to the 
CD-ROM device, and open the file 1_README.TXT.

In addition to the ASCII text (1_README.TXT), this disc 
contains Portable Document Format (PDF) files for viewing and 
searching the report with Adobe Acrobat Reader 3.0 or higher.

To make best use of this CD-ROM, you will need to develop 
some familiarity with Acrobat Reader; an on-line guide is 
available within Acrobat Reader under "Help."

PORTABLE DOCUMENT FORMAT (PDF) FILES 

This disc contains Portable Document Format (PDF) files for 
viewing and searching documents.  In order to view PDF files 
you will need a reader that can translate PDF files.  The 
ACROBAT directory contains installers for Adobe Acrobat 
Reader 3.01 for both Windows (PC directory) and Macintosh 
(MAC directory).  You can use the installers provided on this 
disc or download the latest version of Adobe Acrobat Reader 
free via the Internet from the Adobe homepage on the World 
Wide Web at http://www.adobe.com/ 

If your copy of Acrobat Reader has "File" "Preferences" 
"General..." "Open Cross-Document Links In Same Window" 
selected, you should deselect it.  This will keep the main 
document open while you open and close other PDF files.  
Within the OF98_338.PDF file on this CD-ROM, links (outlined 
text) are provided that allow you to jump to other parts of 
the document and to open the various chapters on the disc.  
This CD-ROM contains a full-text index (INDEX.PDX) that is 
for use in searching the PDF files for words or sets of words 
using the search tool in Acrobat Reader.  

FILES ON CD-ROM

1_README.TXT (This file)
ACROBAT directory (installers for Acrobat Reader)
CHAPTERS directory (PDF files of each of the 23 chapters in 
     the report; these are normally accessed via the 
     OF98_338.PDF file but can be accessed directly if you 
     choose)
INDEX directory (working directories for Acrobat Search)
INDEX.PDX (index file for Acrobat Search)
OF98_338.PDF (the starting or "navigation" PDF for this 
     report with links to the chapters)