DNR Report 246: 1986; Esker Prospecting Over the Duluth Complex in Northeastern Minnesota

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Introduction and objectives extracted from page 1 of the report:

INTRODUCTION AND OBJECTIVES There are at least six general types of platinum (Pt) and/or palladium (Pd) mineralization models applicable to the Late Precambrian Duluth Complex (See Appendix A). Therefore, a project was initiated to evaluate the Pt and Pd potential of the Duluth Complex in Lake and St. Louis Counties. In addition, the potential for Au, Ag, Ti, Cr, Cu, and Ni would also be evaluated. Thus, a reconnaissance-scale glacial esker sampling program for one field season was chosen as the technique to be used. Two esker sample media were analyzed: (a) detrital heavy minerals, which have been the classical approach to prospecting for precious metals within stream sediments and (b) the -63 micron silt and clay fraction for labile base metals and other pertinent indicator elements. The sampling and processing procedures were designed to try to find occurrences of trace amounts (1 to 10 ppb range) of the precious metals in the esker sediments. Such occurrences could be used to search by other methods for the bedrock sources. A graduate student at UMD worked on the project to fulfill the requirements for an M.S. thesis relating to the provenance of materials within these eskers.

Another objective was to determine whether this prospecting method would be an effective regional evaluation tool. It was felt that a significant number of samples would be required to properly evaluate the method.


View or download report

Report 246: Esker Prospecting Over the Duluth Complex in Northeastern Minnesota; stream sediment exploration techniques for Pt-Pd, Au-Ag, Ti, Cr, Cu & Ni.

(30 pages, 8.5 x 11 inches, 1 MB)
Authors: D.P. Martin and M. Eng

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View or download plates

Plate 1-East: East Half of Plate 1, Map of Esker Deposits and Sites Sampled in Northeastern
Minnesota with Selected Assay Results
(1.8 MB)
Author: MN DNR, Division of Lands and Minerals

Plate 1-West: West Half of Plate 1, Map of Esker Deposits and Sites Sampled in Northeastern
Minnesota with Selected Assay Results.

(1.8 MB)
Author: MN DNR, Division of Lands and Minerals


Download GIS data

A zip file containing data for samples extracted from ninety-six heavy mineral concentrates described in the Minnesota Department of Natural Resources (MnDNR), Division of Lands and Minerals Report “Esker Prospecting Over the Duluth Complex in Northeastern Minnesota – Report 246,” published in 1986. Each folder from the zip file contains data from the report in different formats. The data is presented in a Microsoft Access database, dBase IV files, and an ArcGIS file geodatabase. 

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