Historical Valley Floor Sedimentation in the Upper Mississippi Valley

Dados Bibliográficos

ID8375601
AutoresJames C Knox (University of Wisconsin–Madison, autor correspondente)
Ano1987
Volume77
Fascículo2
Páginas224-244
Data de publicação1987-06-01
Peer ReviewedSim
Open AccessNão
TipoARTICLE
PeriódicoAnnals of the Association of American Geographers (JOURNAL)
Identificadores do periódicoISSN: 0004-5608 • E-ISSN: 1467-8306
EditoraInforma UK Limited (PUBLISHER • GB)
DOI10.1111/j.1467-8306.1987.tb00155.x
OpenAlexW1970356481
IdiomaEN
Citações recebidas37
Referências citadas14

This research evaluates the response of floodplain sedimentation rates to post-1820 A.D. human activity in the Lead-Zinc district of the Upper Mississippi Valley. Although mine waste has contributed very minor amounts of sediment to historical overbank floodplain sedimentation that commonly is 30–50 cm deep on tributary floodplains to as much as 3–4 m deep on floodplains in the lower reaches of main valleys near the Mississippi River, it is well represented as trace metals. The dating of stratigraphic horizons was accomplished by matching abrupt rises in the concentration of zinc adsorbed on silt and clay particles with the date of opening of a nearby upstream mining and milling operation. Results show that decadal-scale average historical rates of overbank floodplain sedimentation range from about 0.3 cm/yr to 4.0–5.0 cm/yr and greatly exceed the average presettlement post-glacial (Holocene) floodplain vertical accretion rate of 0.02 cm/yr. Overbank sedimentation rates rose rapidly on both tributary and main valley floodplains in the late nineteenth century, in response to poor agricultural land management and frequent above-average rainfall in the early growing season. By the 1920s large capacity tributary channels developed within the belt of historical channel migration causing a major reduction in the rate of overbank sedimentation, while on the floodplains of main valleys rates of overbank sedimentation continued to increase to a maximum in the 1930s. Since then, rates of overbank sedimentation on both tributary and main valley floodplains have been greatly reduced in response to better land management

Alluvial plain · Floodplain · Fluvial · Geography · Geomorphology · Glacial period · Hydrology (agriculture) · Overbank · Sediment · Sedimentation · Silt · Structural basin · Tributary · Geological formations and processes · Geology · Hydrology and Sediment Transport Processes · Paleontology · Soil erosion and sediment transport