ABSTRACT An organic-rich (gyttja) lake sediment geochemical survey was conducted over Lower Precambrian volcanic and associated rocks in northeastern Minnesota, for the purpose of determining the applicability of this method for evaluation of mineral resource potential and reconnaissance exploration. Two hundred and seventy samples were collected from 75 lakes over an area of 200 square miles (520 sq. km.).
A weak aqua regia leach on unignited gyttja produced the best contrast over background. Statistical analysis of the data indicates that trace element distributions are greatly dependent upon the limnological environment of each lake; trace elements tend to be concentrated in the organic and/or inorganic fractions of the gyttja; and, of all parameters considered, LOI (loss-on-ignition) is the best single indicator of limnological environment.
Due to the variations in lake environments and trace element accumulation in the gyttja, parameters other than the element concentrations were considered. However, the study indicated, even though a perfect datum for comparing lakes was not possible, the element concentrations for arsenic, cobalt, copper, nickel, lead, and zinc provided the best datum for comparing all 75 lakes.
Several significant anomalies were located by the survey. Anomalous copper was found in a lake near an interesting copper prospect. Copper, lead, titanium, and zinc appear to reflect bedrock composition; chromium, magnesium, and nickel reflect both bedrock composition
and glacial dispersion.
Report 73-3-1: Gyttja Lake Sediment Exploration Geochemical Survey of E. L. Vermilion-Ely Area, St.Louis Co. and Lake Co., MN; organic-rich lake sediment survey in T61N-63N R11W-16W; element maps & references.
(41 pages, 8.5 x 11 inches, 2.46 MB)
Authors: D.G. Meineke, M.K. Vadis, and A.W. Klaysmat
Please note: Best results in viewing this report will be obtained by saving the file to a location of your choice and opening with Adobe Reader or Acrobat. Some report information may not display as a result of opening with Acrobat directly from a web browser.
This report has been scanned in and applied with optical character recognition (OCR) which electronically translates the scanned image printed text into machine-encoded text. This allows users to then search the document by keywords in Adobe Reader or Acrobat software.
Plates 1-11: Reside on microfiche at the MN DNR Hibbing office.
Author: MN DNR, Division of Lands and Minerals
See MN DNR Report 376, Minnesota Lake Sediment Geochemistry Surveys for compiled GIS geochemistry data from historic MN DNR lake and stream sediment survey reports including this report, 73-3-1.
500 Lafayette Road
St. Paul, Minnesota 55155-4045
tel. (651) 259-5405
fax (651) 296-5939
Disclaimer and Copyright Protection: Maps, Reports, Data, and Other Information - The State of Minnesota makes no representations or warranties express or implied, with respect to the use of the information contained herein regardless of its format or the means of its transmission. There is no guarantee or representation to the user as to the accuracy, currency, suitability, completeness, usefulness, or reliability of this information for any purpose. The user accepts the information “as is." The State of Minnesota assumes no responsibility for loss or damage incurred as a result of any user’s reliance on this information. All maps, reports, data, and other information contained herein are protected by copyright. Permission is granted to copy and use the materials herein for any lawful noncommercial purpose. Any user of this information agrees not to transmit or provide access to all or any part of this information to another party unless the user shall include with the information a copy of this disclaimer.