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Tertiary Gold-Bearing Channel Gravel in Northern Nevada County, California

Geological Survey Circular 566 - 1968

Here is a great study done by the USGS on the Motherlode! Complete with Maps and Diagrams!

Contents Include:

• Abstract
• Geology of the Channel Gravel
• Introduction
• • Previous work
  • Acknowledgments
• General Geology
• • Bedrock
  • Auriferous Gravel
  • Volcanic Rocks
  • Colluvium
• Tertiary Channel Near North Columbia
• • Configuration of the Channel
  • Grade and Distribution of gold
• Geophysical Investions of the channel gravel
• • Introduction
  • Acknowledgements
• Instrumentation and Field Procedures
• Determination of Bedrock Configuration
• • Seismic Method
  • Gravity Method
  • Magnetic Method
  • Resistivity Method
  • Electromagnetic Method
  • Induced - Polarization Method
• Detection of Tertiary channels under volcanic cover
• Recognition and delineation of the blue gravel
• Location of concentrations of magnetic minerals
• Conclusions
• References Cited

Figures

• Index Map showing loation of area studied
• Geologic map of part of area between the South and Middle Yuba Rivers
• Diagram showing inferred path followed by the Tertiary Yuba River
• Diagrammatic section across and idealized Tertiary channel
• Detailed Geologic map showing location of hydraulic pits and drill holes in the Tertiary gravel in the vicinity ofn North Columbia and Badger Hill
• Subsurface Contour map of bottom of channel near North Columbia as indicated by drill holes
• Cross Section o channel near North Columbia as indicated by one line of drill holes
• Contour map of the foot-assay product as indicated by drilling information

* This document was digitally archived by Sylvanite, Inc. and is not to be used for resale or reproduction. You are not purchasing the original document but a PDF format available for instant download upon purchase.