Browsing by Subject "southeastern Minnesota"

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    Bulletin No. 29. The Paleozoic and Related Rocks of Southeastern Minnnesota
    (Minnesota Geological Survey, 1941) Stauffer, Clinton R.; Thiel, George A.
    The area covered by this report is mainly the southeastern part of Minnesota. It includes that portion of the state lying along or bounded by the St. Croix, the Minnesota, and the Mississippi rivers from Pine County southward to the Iowa state line and from Brown County eastward to the Wisconsin state line. Adjoining areas are referred to at various points in the text, chiefly for correlative purposes or in order to clarify the discussion. This area lies mostly within the hardwood timber section. Numerous towns and villages dot the region, which is part of the more thickly populated area of Minnesota, settled for over seventy-five years and first pioneered over one hundred years ago. Many of the old traders and missionaries traveled its navigable waters early in the seventeenth century; and for untold centuries before that it was an important part of the great hunting ground of the American Indian. The state of Minnesota lies on the southern border of the great Canadian Shield, so that much of its surface is covered by the preCambrian rocks characteristic of that ancient land mass. There more recent sediments overlie these older rocks, they vary in age from Cambrian to Cretaceous and later, for the glacial drift and the recent non-marine sediments may lie directly on the preCambrian. The strand line of Paleozoic and late Mesozoic time often passed through Minnesota; and the position of the ancient shore, varying from time to time, left many unconformities. The significance of some of these unconformities may not yet be fully appreciated, but they range from short breaks (diastems) in sedimentation, like those in the St. Croixian series, to great erosion intervals (disconformities) like that between the Maquoketa formation and the Cedar Valley limestone, where a whole system and fully half of another are wanting. It is evident, therefore, that during these long intervals diastrophism caused the land mass to the north to be extended beyond the boundaries of the state and that during such periods profound erosion must have affected this area, removing an unknown amount of the surface, probably base-leveling it several times.
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    Educational Series 10. Geology of the Root River State Trail Area, Southeastern Minnesota
    (Minnesota Geological Survey, 1999) Mossler, John H.
    The Root River State Trail is a paved walking, bicycling, and cross- country skiing trail in southeastern Minnesota that currently extends from the town of Fountain through Lanesboro to Rushford, and farther east towards Houston. It is maintained by the Minnesota Department of Natural Resources, which operates a trail information center in Lanesboro. The Rushford Historical Society operates a trail rest area in Rushford. The trail is part of a planned network of trails throughout southeastern Minnesota, that will ultimately extend into Iowa and Wisconsin. This guide was developed for the Fountain to Rushford segment of the Root River State Trail, but the information will help you learn more about geologic features you see anywhere in southeastern Minnesota. The Root River State Trailtraverses the unique landscape of Minnesota's 'Historic Bluff Country,' and provides us with a birds-eye- view into the processes that have been forming the rocks and the land surfaces in this part of Minnesota during the past 500 million years. Flat- lying layers of limestone and dolostone form high bluffs above narrow river valleys, such as the Root River valley. The limestone uplands are intensively farmed, but many of the fields contain pits or depressions, called sinkholes, that surface water drains into. The sinkholes are usually overgrown with burr oak, stinging nettle, woodbine, and wild cherry. The Root River has eroded a steep-sided valley into the layers of limestone and dolostone. At the base of the cliffs, water that drained into the sinkholes on the uplands emerges as springs, having traveled through passageways in the limestone and dolostone. This booklet summarizes the history of the rocks that you see as you explore the Root River State Trail, and presents a field guide to features of geologic interest.
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    Guidebook 1. A Geological Field Trip in the Rochester, Minnesota Area
    (Minnesota Geological Survey, 1968) Austin, George S.
    The Minnesota Geological Survey invites non-geologists to examine the rocks and fossils in the Rochester area on this field trip. We welcome all persons regardless of their backgrounds in geology and hope that this guidebook will help make what is seen here more understandable. If any word or explanation is not clear to you, please ask any of the geologists on the trip to explain it to you.
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    Guidebook 4. Field Trip Guide Book for Paleozoic and Mesozoic Rocks of Southeastern Minnesota
    (Minnesota Geological Survey, 1972) Webers, G.F.; Austin, G.S.
    The Paleozoic rocks of southeastern Minnesota (fig. 1) were deposited from a marine sea which occupied the Hollandale Embayment (fig. 2), a shallow depression that extended northward from the Ancestral Forest City Basin (Iowa Basin) onto the cratonic shelf and into Minnesota and Wisconsin in Early and Middle Paleozoic time. The rocks that now remain within the embayment in Minnesota are bordered to the east by nearshore-facies Paleozoic rocks on the Wisconsin Arch, to the northeast by Precambrian rocks that constitute the Wisconsin Dome, and to the north and west by nearshore-facies Paleozoic rocks lying near the margins of the Hollandale Embayment and the Precambrian rocks of the Transcontinental Arch. The embayment overlies older basins and horsts that are bounded by largescale Precambrian faults (Sims and Zietz, 1967). Many smaller Paleozoic basins, depositional barriers, and faults within the embayment probably have resulted from relatively minor recurrent movements along Precambrian faults during Paleozoic time (Craddock and others, 1963).
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    Information Circular 41. Geochemical Investigation of Minor and Trace Elements in the Acid-Insoluble Residues of Lower Paleozoic Carbonate and Related Strata, Southeastern Minnesota-The Data Base
    (Minnesota Geological Survey, 1994) Morey, G.B.; Lively, R.S.; Mossler, John H.; Hauck, S.A.
    The Upper Mississippi Valley mining district in Iowa, Wisconsin, and Illinois is one of several world-class lead-zinc mineral districts in developed Paleozoic strata of the northern Midcontinent. Although Mississippi Valley-type deposits vary considerably from district to district, they are defined as being predominantly sphalerite-galena replacement and vein deposits-including vug and breccia fillings-in carbonate host rocks. In general, they are restricted to certain formations; as such they are peneconformable but clearly crosscutting. Therefore, Mississippi Valley-type mineral deposits are epigenetic and stratabound, but not stratiform. Minor occurrences of base-metal sulfides also are present in calcareous and, to a lesser extent, in shaly and sandy rocks in a broad zone surrounding the main Upper Mississippi Valley lead-zinc district. These outlying occurrences are of special interest because similarities in form, distinctive mineral paragenesis, and sulfur and lead isotope systematics imply that they were cogenetic with mineralization in the main district. The outlying occurrences may represent remnants of fluid pathways associated with mineralization in the main district. To evaluate the extent of mineralization in southeastern Minnesota, we initiated a geochemical study that focused on the minor-and trace-element content of insoluble residues in carbonate rocks, using samples from drill holes and operating quarries throughout southeastern Minnesota (Fig. 2; Tables 4-52 in appendix). Regional geochemical studies of this kind have revealed, even in rocks that appear to be barren of sulfide ores, a suite of metals characteristic of Mississippi Valley-type mineral deposits. In particular, this suite includes Pb, Zn, As, Cu, Ni, Ca, Ag, and Mo. Geochemical analysis of insoluble residues from Paleozoic carbonate rocks has become an integral part of the assessment of mineral resources in the northern Midcontinent (Erickson and others, 1981, 1983; Mosier and Motooka, 1983; Viets and others, 1983). Insoluble residues are the materials remaining after calcium carbonate has been dissolved in a aqueous solution of 5:1 hydrochloric acid. Measurements of the minor-and trace- element composition of the residues provide a rapid, yet sensitive means of identifying regional ground-water flow patterns of metal-bearing brines. The method also appears to have some applicability in identifying previously unrecognized areas with Mississippi Valley-type lead- zinc deposits and, by extension, providing clues to possible locations of mineral deposits in southeastern Minnesota.
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    Information Circular 6. Paleozoic Lithostratigraphic Nomenclature for Southeastern Minnesota
    (Minnesota Geological Survey, 1969) Austin, G.S.
    The Paleozoic lithostratigraphic nomenclature shown in the column was compiled from information obtained from several sources-outcrops, deep cores, and theses on the geology of southeastern Minnesota. It is a revision of the Paleozoic stratigraphic column published in 1956 (Schwartz, 1956). The purpose of this discussion is to describe the Paleozoic strata of southeastern Minnesota in terms of the revised nomenclature and to call attention to related post-1956 publications and other source materials.
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    OFR14-02, Geologic controls on groundwater and surface water flow in southeastern Minnesota and its impact on nitrate concentrations in streams
    (Minnesota Geological Survey, 2014) Runkel, Anthony C.; Steenberg, Julia R.; Tipping, Robert G.; Retzler, Andrew J.
    This report summarizes the results of a Minnesota Geological Survey (MGS) investigation conducted for the Minnesota Pollution Control Agency (MPCA) designed to support watershed planning efforts in southeast Minnesota. Specifically it provides better understanding of the geologic controls on nitrate transport in the region, including nitrate in groundwater that is the source of baseflow to streams. Nitrate contamination of surface water and groundwater is a long- standing issue in southeastern Minnesota. We focused much of our investigation on an evaluation of nitrate (NO3 ion) transport in the Root River watershed because of the relatively advanced understanding of the karstic conditions in that area. However, the overall scope of the project includes the entire bedrock-dominated landscape of southeast Minnesota. Our results therefore support a broader MPCA watershed planning effort that directly pertains to the Root River, as well as to other watersheds within the Lower Mississippi River Basin in Minnesota.
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    OFR14-03, Geologic Controls on Groundwater and Surface Water Flow in Southeastern Minnesota and its Impact on Nitrate Concentrations in Streams: Local Project Area Report
    (Minnesota Geological Survey, 2014) Steenberg, Julia R.; Tipping, Robert G.; Runkel, Anthony C.
    This report summarizes the results of part of a Minnesota Geological Survey (MGS) investigation conducted for the Minnesota Pollution Control Agency (MPCA) designed to support watershed planning efforts in southeast Minnesota. The broader project provides better understanding of the geologic controls on nitrate transport in the region, including nitrate in groundwater that is the source of baseflow to streams. This report describes a local scale subproject focused on a relatively small part of the Root River watershed in Fillmore County. We conducted new mapping that provides a more detailed depiction of the geologic conditions in a three dimensional electronic format suitable for groundwater-surface water modeling. In addition, we used existing maps and reports along with new field data collected during the course of this project to improve the hydrostratigraphic characterization of the bedrock. This led to a more comprehensive understanding of the hydrostratigraphic attributes of bedrock that forms the Upper Carbonate Plateau, which dominates the landscape in the local project area. Cross sections within the local project area are used to illustrate how nitrate is transported in the ground and surface water system.