Skip Links

USGS Home
Contact USGS
Search USGS

Prepared in cooperation with the U.S. Department of Agriculture (USDA) Forest Service

Earth Science Studies in Support of Public Policy Development and Land Stewardship—Headwaters Province, Idaho and Montana

By U.S. Geological Survey Headwaters Province Project Team

Karen Lund, Scientific Editor

The USGS Headwaters Province project in western Montana and northern and central Idaho was designed to provide geoscience data and interpretations to Federal Land Management Agencies and to respond to specific concerns of USDA Forest Service Regions 1 and 4. The project has emphasized development of digital geoscience data, GIS analyses, topical studies, and new geologic interpretations. Studies were designed to more completely map lithologic units and determine controls of deformation, magmatism, and mineralizing processes. Topical studies of geologic basement control on these processes include study of regional metallogenic patterns and their relation to the composition and architecture of underlying, unexposed basement; timing of igneous and hydrothermal systems, to identify regionally important metallogenic magmatism; and the geologic setting of Proterozoic strata, to better understand how their sedimentary basins developed and to define the origin of sediment-hosted mineral deposits. Interrelated products of the project are at complementary scales.

Version 1.0 Posted December 2007 Circular PDF (15.2 MB)

U.S. Geological Survey Headwaters Province Project Team (Karen Lund, scientific ed.), 2007, Earth science studies in support of public policy development and land stewardship—Headwaters province, Idaho and Montana: U.S. Geological Survey Circular 1305, 92 p.

Contents

Introduction

Digital GIS-Based Geoscience Databases

Preparation of the Digital Geologic Map for the Headwaters Province Project, by Gregory N. Green

Planning

Database Design

Conclusions

Compilation and Interpretation for New Geologic Maps, by Karl V. Evans and Gary L. Jackson

Background

Use of Geologic Map Data Set in Producing a National Forest Soils Map

Statistical Integration and Geochemical Surface Modeling of the NURE and USGS Geochemical Databases, by Robert R. Carlson and Gregory K. Lee.

Methods of Study

Analysis

Surface Modeling and Geographic Information Systems (GIS)

Results

Integrative Geologic Framework of the Headwaters Province

Architecture of the Geologic Basement, by J. Michael O’Neill, P.K. Sims, and Karen Lund

Metallogeny in the Context of the Great Falls Tectonic Zone

Control of Epigenetic Metal Deposits by Paleoproterozoic Basement Architecture, by Terry L. Klein and P.K. Sims

Geochronology and Geochemistry of the Idaho-Montana Porphyry Belt, by Cliff D. Taylor, Jeffrey A. Winick, Daniel M. Unruh, and Michael J. Kunk

Field Work and Classification of Occurrences by Deposit Type

⁴⁰Ar/³⁹Ar Geochronology

Whole-Rock Geochemistry and Radiogenic Isotopic Studies

Conclusions

SHRIMP U-Pb and ⁴⁰Ar/³⁹Ar Age Constraints for Relating Plutonism and Mineralization in the Boulder Batholith Region, Montana, by Karen Lund, John N. Aleinikoff, Michael J. Kunk, and Daniel M. Unruh

Geochronologic Results

Interpretations

Use of Multiple Techniques

Impacts

Stratigraphy and Structure of Proterozoic Strata of Central Idaho

Mesoproterozoic Strata of East-Central Idaho, by Karl V. Evans, Russell G. Tysdal, and Karen Lund

Blackbird Gold-Bearing Cobalt-Copper Deposits, East-Central Idaho—Reevaluation of Stratigraphic and Structural Setting, by Karen Lund, Russell G. Tysdal, Karl V. Evans, and Michael J. Kunk

Stratigraphy

Metamorphism and Deformation

Deposits

Conclusions

Implications

Identification of Neoproterozoic Windermere Supergroup, Central Idaho, using Geologic Mapping and SHRIMP U-Pb Geochronology—Implications for Neoproterozoic Rifting and Glaciation, by Karen Lund, John N. Aleinikoff, and Karl V. Evans

Stratigraphy

Geocronology

Results

Implications for Models of Snowball Earth and Rifting of Rodinia

Mineral Resources in Relation to Potential Regional Environmental Effects

Baseline Geochemistry of a Part of the Salmon River Drainage—Two Examples, by Robert G. Eppinger, Paul H. Briggs, and Betsy Rieffenberger

Methods

Example 1. Geochemical Contrasts Between Two Adjacent Basins

Example 2. Assessing Effects of Wildfire on Stream Sediment and Water Geochemistry

Geochemical Signatures of Diverse Mineral Deposit Types in the Upper Salmon River Watershed, Central Idaho, by Bradley S. Van Gosen, Robert G. Eppinger, Jane M. Hammarstrom, Paul H. Briggs, and D.W. Peters

Reconnaissance Geochemical Study

Study Methods

Water Samples

Solid Samples

Results

Highlights

Acid-Rock Drainage

Lithologic Controls on Water Quality

Arsenic

Environmentally Significant Metals in Mine Wastes, Mill Tailings, and Stream Sediments

Conclusions

Applications of the Study

Summary

References Cited