Browsing by Subject "surface geology"

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    Bulletin No. 13. Surface Formations and Agricultural Conditions of Northeastern Minnesota
    (Minnesota Geological Survey, 1917) Leverett, Frank; Sardeson, Frederick W.; Purssell, U.G.
    This bulletin is a preliminary paper which treats the soils of only the northeast quarter of Minnesota. It will be followed by a report on the entire state, the field work for which already has been completed. The work has been done in accordance with the agreement for cooperation between the United States Geological Survey and the Minnesota Geological Survey, entered into, March, 1912. By this agreement the services of Mr. Frank Leverett were secured for surveying the surface formations and soils. Mr. Leverett has been engaged since 1886, or thirty years, in studying the surface geology of the Great Lakes region and because of his large experience in the greater area he was particularly well prepared to undertake the studies in Minnesota. He has spent, moreover, considerable time in the state studying its physiography in connection with the preparation of a monograph for the United States Geological Survey. Since the reorganization of the State Survey, the salary of Mr. Leverett has been met by the United States Geological Survey, while the greater part of his expenses have been paid by the State Survey. The State Survey has provided also for this work the services and expenses of Professor F. W. Sardeson, who has assisted in this work for the past five seasons. For a short period, also, the State has supplied the services of Dr. Arthur H. Elftman. We wish to acknowledge the generous assistance of the Division of Soils of the Department of Agriculture of the University of Minnesota and of the United States Bureau of Soils. The valuable contributions to the knowledge of the surface formations of Minnesota by the Minnesota Geological and Natural History Survey, under the direction of Professor N. H. Winchell, particularly those of Mr. Warren Upham of that Survey, have aided greatly in the preparation of this report. The section on climatic conditions in Minnesota has been generously contributed without any cost to the Survey by Mr. U. G. Purssell, Director of the Minnesota Section of the United States Weather Bureau. In the preparation of the maps and other data showing dates of killing frosts, lengths of growing season, rainfall, etc., Professor C. J. Posey has rendered efficient service.
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    Bulletin No. 14. Surface Formations and Agricultural Conditions of The South Half of Minnesota
    (Minnesota Geological Survey, 1919) Leverett, Frank; Sardeson, Frederick W.; Purssell, U.G.
    This bulletin treats the soils of only the south half of Minnesota. The field embraced includes the part of the state south from the median line, which is near latitude 46° 25'. Following the plan in Bulletin No. 12, on Northwestern Minnesota, a brief general description of the surface features and deposits of the entire state is given, and the climate of the entire state also is discussed. It will be followed by a report on the entire state, the field work for which already has been completed. The work has been done in accordance with the agreement for cooperation between the United States Geological Survey and the Minnesota Geological Survey, entered into, March, 19I2. By this agreement the services of Mr. Frank Leverett were secured for surveying the surface formations and soils. Mr. Leverett has been engaged since 1886, or thirty-two years, in studying the surface geology of the Great Lakes region and because of his large experience in the greater area he was particularly well prepared to undertake the studies in Minnesota. He has spent, moreover, considerable time in the state studying its physiography in connection with the preparation of a monograph for the United States Geological Survey. Since the reorganization of the State Survey, the salary of Mr. Leverett has been met by the United States· Geological Survey, while the greater part of his expenses have been paid by the State Survey. The State Survey has provided also for this work· the services and expenses of Professor F. W. Sardeson, who has assisted· in this work for five seasons. We wish to acknowledge the generous assistance of the Division of Soils of the Department of Agriculture of the University of Minnesota and of the United States Bureau of Soils. The valuable contributions to the knowledge of the surface formations of Minnesota by the Minnesota Geological and Natural History Survey under the direction of Professor N. H. Winchell, particularly those of Mr. Warren Upham of that survey, have aided greatly in the preparation of this report. The section on climatic conditions in Minnesota has been generously contributed without any cost to the Survey by Mr. U. G. Purssell, Director of the Minnesota Section of the United States Weather Bureau. In the preparation of the maps and other data showing dates of killing frosts, lengths of growing season, rainfall, etc., Professor C. J. Posey has rendered efficient service.
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    Geologic Map Series 3. Geology of the Cloquet Quadrangle Carlton County, Minnesota
    (Minnesota Geological Survey, 1970) Wright, H.E. Jr; Mattson, L.A.; Thomas, J.A.
    The Cloquet quadrangle is bisected by the St. Louis River, a major stream that flows into the western end of Lake Superior. Precambrian rocks are extensively exposed in the river valley where overlying Pleistocene glacial deposits have been eroded. The Precambrian rocks are dominated by the Thomson Formation, which consists of interbedded slates, slaty graywackes, and graywackes. Small-scale cross-bedding, graded bedding, flute casts, load casts, clastic dikes, and other primary and penecontemporaneous structures are common, as are calcareous and siliceous concretions. The formation probably was deposited in a relatively deep-water basin, in part by turbidity currents. It has only one conspicuous marker bed, the Otter Creek unit, so the stratigraphic thickness across the intricate folds of the region is difficult to determine, but it probably is about 20,000 feet. Normal and reverse faults with displacements of a few tens of feet are common, as are steeply dipping conjugate joints of northwest and northeast trends. Cleavage is well developed in slaty units. The Thomson Formation is correlated with the Animikie Group. Abundant microgabbro dikes were intruded during subsidence of the Lake Superior syncline. The Pleistocene glacial history was marked by three phases of advance and retreat of the Superior Lobe, preceded by a phase of the Rainy Lobe. Drumlins, moraines, outwash plains, eskers, lake plains, and diversion channels constitute distinctive landforms. During final withdrawal of the Superior Lobe from the area, the St. Louis River, which carried the outflow from Glacial Lake Upham, was diverted to form prominent erosional channels leading to the St. Croix River at progressively lower elevations, until it finally flowed into the proglacial Lake Nemadji, whose outlet formed a final channel in the sequence.