U.S. Geological Survey
Data Series 439
Version 1.0


Geochemical database for igneous rocks of the
ancestral Cascades arc--Southern segment, California and Nevada

By Edward A. du Bray, David A. John, Keith Putirka, and Brian L. Cousens

U.S. DEPARTMENT OF THE INTERIOR
KEN SALAZAR, Secretary

U.S. GEOLOGICAL SURVEY
Suzette M. Kimball, Acting Director

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Introduction

Volcanic rocks that form the southern segment of the Cascades magmatic arc are 
an important manifestation of Cenozoic subduction and associated magmatism in 
western North America.  Until recently, these rocks had been little studied and 
no systematic compilation of existing composition data had been assembled.  This 
report is a compilation of all available chemical data for igneous rocks that 
constitute the southern segment of the ancestral Cascades magmatic arc and 
complement a previously completed companion compilation that pertains to rocks 
that constitute the northern segment of the arc.  Data for more than 2,000 
samples from a diversity of sources were identified and incorporated in the 
database.  The association between these igneous rocks and spatially and 
temporally associated mineral deposits is well established and suggests a 
probable genetic relationship.  The ultimate goal of the related research is an 
evaluation of the time-space-compositional evolution of magmatism associated 
with the southern Cascades arc segment and identification of genetic 
associations between magmatism and mineral deposits in this region.


Contact Information

Inquiries about this CD-ROM should be addressed to:

Edward A. du Bray
U.S. Geological Survey
Box 25046, Mail Stop 973
Denver Federal Center
Denver, CO 80225-0046

Telephone: (303) 236-5591
E-mail: edubray@usgs.gov

Disclaimer

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the use of these data.

Using This CD

The descriptive and interpretive text chapter of this volume is in Portable 
Document Format (PDF).  Use Acrobat Reader to access the chapter.

The PDF chapter is accessible as defined by Section 508 of the Rehabilitation 
Act.

Contents of This CD-ROM

When the CD is opened, the following items appear on the screen:

DATABASE folder-Contains two files: SW Casc geochem DB.xls and 
  SW Casc geochem DB.txt.
DS_439.pdf
ReadMe.txt

The PDF file contains text that describes the database and how it was compiled.  
The XLS file is the database itself as a Microsoft Excel spreadsheet; the TXT 
file is the main database as a tab-delimited text file.

System Requirements

Adobe Reader MS Windows

Intel Pentium-class processor
Windows XP Professional or Home Edition with SP1 or SP2, or Tablet PC Edition; 
Microsoft Windows 2000 with Service Pack 2 (SP2)
128 MB of RAM
90 MB of available hard-disk space for the full version
800 x 600 monitor resolution


Adobe Reader Macintosh

PowerPC G3, G4, G5 processor
Mac OS X v.10.2.8 or 10.3
128 MB of RAM
80 MB of available hard disk space (110 MB required for the full version)
800 x 600 screen resolution