Meander Loops and the Cahokia Site

AbstractThe locations of certain mounds at the Cahokia site indicate that the rate of Mississippi River channel migration in the American Bottoms in the Upper Mississippi Valley has differed from the rate of channel movement in the Lower Mississippi Valley. The American Bottoms was probably the most favorable section of the Mississippi River Valley for long-term prehistoric settlement with regard to location within the present meander belt of the river.

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AMS Radiocarbon Age of the Upper Mississippi Valley Roxana Silt

Quaternary Research ◽

10.1006/qres.1993.1035 ◽

1993 ◽

Vol 39 (3) ◽

pp. 282-289 ◽

Cited By ~ 38

Author(s):

David S. Leigh ◽

James C. Knox

Keyword(s):

Mississippi River ◽

River Valley ◽

Sedimentation Rates ◽

Mississippi Valley ◽

Mississippi River Valley ◽

Radiocarbon Age ◽

Environmental Controls ◽

Type Area ◽

Central Illinois

AbstractAccelerator mass spectrometer radiocarbon ages of the Roxana Silt (loess) along the Upper Mississippi Valley of Wisconsin and Minnesota indicate that loess sedimentation of the Roxana Silt occurred between about 55,000 and 27,000 14 C yr B.P. However, due to local environmental controls, the basal age at any given site may range from 55,000 to 35,000 14C yr B.P. The radiocarbon ages presented here are in agreement with previous radiocarbon ages for the Roxana Silt in its type area of west-central Illinois, but indicate that long-term sedimentation rates along the bluffline of the Upper Mississippi Valley were very slow (4-8 cm/1000 yr) compared to long-term sedimentation rates along the bluffline of the type area (40-70 cm/1000 yr). Comparison of radiocarbon ages for midcontinent middle Wisconsinan loess deposits indicates that sedimentation along the Mississippi River valley may have preceded loess sedimentation along the Missouri River valley by as much as 20,000 yr or that basal ages for middle Wisconsinan loess along the Missouri Valley are erroneously young. The bracketing ages for the Upper Mississippi Valley Roxana Silt indicate that the Mississippi River valley was receiving outwash sedimentation between 55,000 and 27,000 14C yr B.P.

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Carbon Dioxide Emissions as Affected by Alternative Long-Term Irrigation and Tillage Management Practices in the Lower Mississippi River Valley

The Scientific World JOURNAL ◽

10.1155/2014/626732 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

S. F. Smith ◽

K. R. Brye

Keyword(s):

Carbon Dioxide ◽

Soil Respiration ◽

Mississippi River ◽

Management Practices ◽

River Valley ◽

Mississippi River Valley ◽

Growing Seasons ◽

Lower Mississippi River ◽

Lower Mississippi River Valley

Ensuring the sustainability of cultivated soils is an ever-increasing priority for producers in the Lower Mississippi River Valley (LMRV). As groundwater sources become depleted and environmental regulations become more strict, producers will look to alternative management practices that will ensure the sustainability and cost-effectiveness of their production systems. This study was conducted to assess the long-term (>7 years) effects of irrigation (i.e., irrigated and dryland production) and tillage (conventional and no-tillage) on estimated carbon dioxide (CO2) emissions from soil respiration during two soybean (Glycine maxL.) growing seasons from a wheat- (Triticum aestivumL.-) soybean, double-cropped production system in the LMRV region of eastern Arkansas. Soil surface CO2fluxes were measured approximately every two weeks during two soybean growing seasons. Estimated season-long CO2emissions were unaffected by irrigation in 2011 (P>0.05); however, during the unusually dry 2012 growing season, season-long CO2emissions were 87.6% greater (P=0.044) under irrigated (21.9 Mg CO2ha−1) than under dryland management (11.7 Mg CO2ha−1). Contrary to what was expected, there was no interactive effect of irrigation and tillage on estimated season-long CO2emissions. Understanding how long-term agricultural management practices affect soil respiration can help improve policies for soil and environmental sustainability.

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Long-term measurements of agronomic crop irrigation made in the Mississippi delta portion of the lower Mississippi River Valley

Irrigation Science ◽

10.1007/s00271-017-0543-y ◽

2017 ◽

Vol 35 (4) ◽

pp. 297-313 ◽

Cited By ~ 20

Author(s):

Joseph H. Massey ◽

C. Mark Stiles ◽

Josh W. Epting ◽

R. Shane Powers ◽

David B. Kelly ◽

...

Keyword(s):

Mississippi River ◽

Mississippi Delta ◽

River Valley ◽

Mississippi River Valley ◽

Lower Mississippi River ◽

Made In ◽

Lower Mississippi River Valley ◽

Crop Irrigation

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Evolution and zoogeography of the invertebrate cave faunas of the Driftless Area of the Upper Mississippi River Valley of Iowa, Minnesota, Wisconsin, and Illinois, U.S.A.

Canadian Journal of Zoology ◽

10.1139/z90-012 ◽

1990 ◽

Vol 68 (1) ◽

pp. 73-88 ◽

Cited By ~ 9

Author(s):

Stewart B. Peck ◽

Kenneth Christiansen

Keyword(s):

Mississippi River ◽

River Valley ◽

Early Pleistocene ◽

Upper Mississippi River ◽

Mississippi River Valley ◽

Glacial Ice ◽

Driftless Area ◽

Long Term Survey

This paper reports the results of a long-term survey of the invertebrates living in caves and other subterranean habitats in the Upper Mississippi River Valley, particularly in the region frequently but erroneously called the Driftless Area. Sixteen troglobitic species are known: two flatworms, two amphipods, one isopod, four spiders, one mite, and six collembolans. The terrestrial troglobite fauna probably represents cave invasion and isolation following Early Pleistocene glaciation, and demonstrates that the caves were habitable while the region was at the margin of Late Pleistocene glaciations. The groundwater troglobite fauna may have survived in situ while the region was covered by glacial ice in the Early Pleistocene. The troglophile fauna consists of at least 78 species, and these species may or may not have come into the region since the Wisconsinan glaciation recession. The presence of troglophile species in a particular cave is highly sporadic.

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