Further Studies on the Pleistocene Geology of Northwestern Iowa

Carman, J. Ernest

doi:10.17077/2160-5270.1248

Cited by 3 publications

(6 citation statements)

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“…1). Peoria Loess is found in the north-south-trending,~300 km long, Loess Hills area of western Iowa and part of adjacent Missouri, with thicknesses ranging from~25 tõ 40 m. Loess in western Iowa has attracted the attention of geologists for almost a century (Carman, 1917(Carman, , 1931Kay and Apfel, 1929;Hutton, 1947;Ruhe, 1954Ruhe, , 1969Ruhe, , 1983Simonson and Hutton, 1954;Daniels and Handy, 1959;Daniels et al, 1960;Bettis, 1990;Forman et al, 1992;Muhs andBettis, 2000, 2003;Forman and Pierson, 2002). Despite the many years of study, there are still uncertainties about the depositional history of loess in western Iowa.…”

Section: Introductionmentioning

confidence: 99%

“…Ruhe (1983) offered two explanations for these differences: (1) the oldest Peoria Loess was derived from a non-calcareous (and possibly non-glacial) source and (2) the lower zones were subjected to syndepositional leaching during an initial period of slower loess sedimentation. It has long been thought that Peoria Loess in western Iowa was derived from outwash on the Missouri River floodplain during the last glacial period (Carman, 1917;Kay and Apfel, 1929;Carman, 1931;Simonson and Hutton, 1954;Ruhe, 1969Ruhe, , 1983. Loess thins eastward from the Missouri River floodplain, displaying decreases in thickness that can be described mathematically (Ruhe, 1954;Muhs and Bettis, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Chronology and provenance of last-glacial (peoria) loess in western iowa and paleoclimatic implications

et al. 2013

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S.; Paces, James B.; and Reynolds, Richard L., "Chronology and provenance of last-glacial (Peoria) loess in western Iowa and paleoclimatic implications" (2013 Geologic archives show that the Earth was dustier during the last glacial period. One model suggests that increased gustiness (stronger, more frequent winds) enhanced dustiness. We tested this at Loveland, Iowa, one of the thickest deposits of last-glacial-age (Peoria) loess in the world. Based on K/Rb and Ba/Rb, loess was derived not only from glaciogenic sources of the Missouri River, but also distal loess from non-glacial sources in Nebraska. Optically stimulated luminescence (OSL) ages provide the first detailed chronology of Peoria Loess at Loveland. Deposition began after~27 ka and continued until~17 ka. OSL ages also indicate that mass accumulation rates (MARs) of loess were not constant. MARs were highest and grain size was coarsest during the time of middle Peoria Loess accretion,~23 ka, when~10 m of loess accumulated in no more thañ 2000 yr and possibly much less. The timing of coarsest grain size and highest MAR, indicating strongest winds, coincides with a summer-insolation minimum at high latitudes in North America and the maximum southward extent of the Laurentide ice sheet. These observations suggest that increased dustiness during the last glacial period was driven largely by enhanced gustiness, forced by a steepened meridional temperature gradient.Published by Elsevier Inc. on behalf of University of Washington.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chronology and provenance of last-glacial (peoria) loess in western iowa and paleoclimatic implications

et al. 2013

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“…Most correlation of Quaternary glacial units was determined from outcrop descriptions and geomorphic features. The first surficial geologic maps of Iowa utilized a five-part till stratigraphy including the Wisconsinan, Iowan, Illinoian, Kansan and Nebraskan (Kay and Apfel, 1929;Kay and Graham, 1943), although there was some level of disagreement as to the correlation and extent of the Iowan (Carman, 1931;Leverett and Sardeson, 1932). Researchers believed a till existed between the Late Wisconsinan and 'Kansan' sediments, but could not agree upon its age or relationship with the 'Iowan'.…”

Section: Stratigraphymentioning

confidence: 99%

“…Based on the regional distribution and stratigraphic position, researchers in Iowa had long identified sediments from a post-Illinois, pre-Late Wisconsin Episode ice advance, but correlation and timing were problematic. These deposits were most commonly referred to as the Iowan by early researchers (Carman, 1931;Leverett and Sardeson, 1932;Kay and Graham, 1943) and later as the Tazewell drift (Ruhe, 1950(Ruhe, , 1969 or 'Till 2' (Kemmis et al, 1981). The Iowa Geological Survey (IGS) has since given the sediments the designation of the Sheldon Creek Formation, but a formal description and nomination of type section has not been provided until now.…”

Section: Introductionmentioning

confidence: 99%

Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA

Tassier‐Surine,

Kerr,

Kilgore

et al. 2024

J Quaternary Science

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A pre‐Late Wisconsinan, post‐Illinoian, till sheet has long been recognized in north‐central Iowa, but has not been formally recognized or defined until now. Early researchers referred to these deposits as the ‘Tazewell’, and the term ‘Sheldon Creek’ was more recently used informally by the Iowa Geological Survey in guidebooks and reports. Recent mapping has extended the eastern margin significantly past previous interpretations. The Sheldon Creek Formation has similar lithologic characteristics to the overlying Alden Member of the Dows Formation, and the two units are distinguished mainly by stratigraphic position. Differentiation from underlying Pre‐Illinoian till units is accomplished using lithology, primarily matrix grain‐size and sand fraction lithology. A suite of 22 radiocarbon ages indicate two distinct, separate groupings within the Sheldon Creek data. These data strongly suggest ice advanced south to 42° N twice, once during Marine Isotope Stage (MIS) 3 and again during late MIS 3 or possibly early MIS 2. The presence of the Laurentide Ice Sheet in northern Iowa during MIS 3 has significant implications for ice sheet reconstructions during this interval.

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“…interpretations of the stage of the drift to the west of the DML alternated between being Kansan, Iowan, or Wisconsinan for half of a century (Carman, 1917;Leverett, 1929;Carman, 1931;Leverett, 1939;Smith and Riecken, 1947). Eventually, Ruhe (1950b) (Ruhe, 1950a).…”

Section: Search For a Middle Wisconsinan Glaciationmentioning

confidence: 99%

Middle to early-late Wisconsin glaciation in north central Iowa

Kerr¹

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Further Studies on the Pleistocene Geology of Northwestern Iowa

Cited by 3 publications

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Chronology and provenance of last-glacial (peoria) loess in western iowa and paleoclimatic implications

Chronology and provenance of last-glacial (peoria) loess in western iowa and paleoclimatic implications

Defining the Sheldon Creek Formation, a Middle Wisconsinan (MIS 3) till in Iowa, USA

Middle to early-late Wisconsin glaciation in north central Iowa

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