Information Circular 40. Scientific and Exploration Drilling in Northwestern Minnesota

Abstract

Scientific test drilling in northwestern Minnesota was undertaken by the Minnesota Geological Survey (MGS) primarily to elucidate the geology of Precambrian and Phanerozoic bedrock in this area where the bedrock is buried beneath several hundred feet of Quaternary glacial sediment. The results of this drilling of 23 holes, and of selected logging, and analyses of the approximately 80 archived records and core from previous drilling, are presented in this report. These data, in conjunction with various geophysical maps, were utilized by the authors and others to construct a series of new geologic maps of northwestern Minnesota that are part of MGS Open-File Report 93- lA (Jirsa and others, 1993). Parts of that report will soon be published in the MGS Miscellaneous Map Series. An important secondary objective of this project is to describe the Quaternary deposits that overlie bedrock, though no systematic regional interpretation of those deposits has been undertaken to date. This is the seventh information circular since 1980 to report the results of test drilling by the Minnesota Geological Survey. Figure 1 shows the areas covered by those earlier studies in relation to this study area in northwestern Minnesota.