Stratigraphic Relations of the Shakopee Dolomite and the St. Peter Sandstone in Southwestern Wisconsin

Flint, Arthur E.

doi:10.1086/626373

Cited by 5 publications

(5 citation statements)

References 5 publications

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“…The Middle Ordovician St. Peter Sandstone Formation represents a particularly important resource for southern Wisconsin in terms of groundwater supply and quarried silica sand. As a result, the spatial distribution of the St. Peter Sandstone and its unconformable contact with the underlying Prairie du Chien Group dolostones has been extensively studied over the past 60+ years (e.g., Flint 1956;Buschbach 1961;Thwaites 1961;Palmquist 1969). The highly variable thickness of the St. Peter Sandstone across Wisconsin reflects the irregular sub-St. Peter erosional surface, an interregional unconformity referred to as the Sauk-Tippecanoe unconformity (Sloss 1963).…”

Section: Introductionmentioning

confidence: 99%

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Steelman¹,

Meyer

Parker

2017

Groundwater

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Organic solvent (i.e., dense nonaqueous phase liquid, DNAPL) migration in the subsurface is known to be extremely sensitive to geologic heterogeneity. There is often a focus on heterogeneity that results from changing depositional conditions over short spatial scales. Similar or even more extreme spatial heterogeneity can result postdeposition due to erosional processes. This study applies a synergistic approach based on a combination of high-resolution lithologic logs of continuous cores, borehole geophysical logs, surface electrical resistivity, and seismic refraction tomography models to assess spatial heterogeneity in a shallow bedrock sequence subject to multiple unconformities and contaminated with a mixture of organic chemicals. The persistence of DNAPL in the source zone and an associated dissolved-phase plume led to variable impacts on formation resistivity across the study site. Seismic refraction in combination with electrical resistivity tomography improved interpretation of highly irregular erosional boundaries by delineating sharp lateral transitions in lithologic composition near the source zone and across the dissolved-phase plume. Electrical resistivity was effective at differentiating between clean and mud-rich sandstones and their unconformable contact with an underlying dolostone. Geophysical measurements revealed eroded dolostone mounds encased by a network of younger mud-rich sandstones channelized by clean semi-lithified sand, all of which was buried beneath variable glacial drift. Our synergistic multidimensional approach resulted in the development of a detailed three-dimensional shallow bedrock geospatial model, which has led to an improved understanding of DNAPL migration and contaminant plume heterogeneity.

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Section: Introductionmentioning

confidence: 99%

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Steelman¹,

Meyer

Parker

2017

Groundwater

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“…Spurr (1924), Emmons (1929), Behre (1935), Behre and others (1937), and Bastin and others (1939) reported on the nature and origin of the district structures and on the origin of the ores. Interest in the district later was renewed with important studies by Willman and Eeynolds (1947), Heyl and others (1945Heyl and others ( , 1948Heyl and others ( , 1955Heyl and others ( , 1959, Agnew and others (1956), Flint (1956), J. W. Allingham (written communciation), and A. F. Agnew (writtten communication).…”

Section: Previous Workmentioning

confidence: 98%

“…Percival 1855, Hall and Whitney (1862), Chamberlin (1877, p. 268-290 and 138-140), Calvin (1894), Sardeson (1916), and Flint , .UP.PER MISSISSIPPI VALLEY-ZINC-LEAD DISTRICT , (1956) argued that the irregular upper surface was due to irregularities in deposition. Numerous outcrops and quarries north, west, and east of the mapped area were examined in detail by Flint (1956), who attributed relief on the contact of the Shakopee dolomite and the St. Peter sandstone to dome structures within the Prairie du Chien. No complete dome can be seen, but enough data can be found to establish the nature of the structure.…”

Section: Prairie Dtt Chien Groupmentioning

confidence: 99%

Geology of the Montfort and Linden quadrangles, Wisconsin

Carlson¹

1961

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PLATE 8. Geologic map of the Montfort and Linden quadrangles, Wisconsin. 9. Typical stratigraphic section of rocks exposed in the Montfort and Linden quadrangles. Page FIGURE 19. Index map of southwest Wisconsin, northwest Illinois, and northeast Iowa_____________________________________ 97 20. Cross section of drill holes showing relations between St. Peter sandstone and Prairie du Chien group________.______-__-103 21. Diagram showing idealized cross section of gash-vein and pitchand-flat deposits.._________-__-______.__-__-________- .

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“…1 and 6;Flint, 1956). The Readstown Member is in turn overlain by fine-grained quartz arenite of the Tonti Member.…”

Section: Sequence IV Willow River Member Of the Shakopee Formationmentioning

confidence: 99%

Sequence stratigraphy of the Prairie du Chien Group, Lower Ordovician, Midcontinent, U.S.A

Smith¹,

Byers²,

Dott³

1996

Paleozoic Sequence Stratigraphy; Views From the North American Craton

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The Oneota and Shakopee Formations of the Lower Ordovician Prairie du ChienGroup compose the Sauk C 1 and C 2 second-order sequences, or supersequences, which are recognized in both outcrop and the subsurface. These second-order sequences are bounded by type 1 sequence boundaries, the regional CambrianOrdovician, mid-Lower Ordovician, and Lower to Middle Ordovician (SaukTippecanoe) unconformities. Karst development and patchy silicification beneath all three sequence boundaries indicate regional subaerial exposure of the outcrop area during unconformity development. In outcrop the Lower Ordovician Prairie du Chien Group consists of four depositional sequences corresponding to the Stockton Hill and Hager City Members of the Oneota Formation and New Richmond and Willow River Members of theShakopee Formation. These four depositional sequences correspond to the Sauk C 1.1, C 1.2, C 2.2, and C 2.3 third-order sequences, each pair of which is separated by a type 2 sequence boundary.Sequences within the Prairie du Chien Group can be subdivided into systems tracts typically composed of one or two laterally continuous minor lithofacies. Individual systems tracts are composed of meter-scale, shoaling-upward parasequences, but parasequence sets have not yet been identified within Prairie du Chien strata. on March 13, 2015 specialpapers.gsapubs.org Downloaded from

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Stratigraphic Relations of the Shakopee Dolomite and the St. Peter Sandstone in Southwestern Wisconsin

Cited by 5 publications

References 5 publications

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Multidimensional Investigation of Bedrock Heterogeneity/Unconformities at a DNAPL‐Impacted Site

Geology of the Montfort and Linden quadrangles, Wisconsin

Sequence stratigraphy of the Prairie du Chien Group, Lower Ordovician, Midcontinent, U.S.A

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