Surface and Subsurface Geologic Conditions Along Selected Reaches of the Mississippi River from Rosedale, Mississippi to Lake Providence, Louisiana.
Abstract
Continuous acoustic subbottom profiling was conducted in 100 miles of the Mississippi River channel near Lake Providence, La., and from below Greenville, Miss., upstream to Rosedale, Miss. Subbottom profiling and other geologic, hydrographic, and topographic data were analyzed to determine the depth, composition, and extent of important geologic horizons beneath the channel and surficial deposits adjacent to the channel in the floodplain. The Tertiary surface as well as bedding and structure within the Tertiary were interpreted from the subbottom profiles for most of the survey area. The geology and stream geometry (thalweg slope and sinuosity) were compared for the river segments studied to determine their relationship to stream degradation and aggradation. Geologic profiles and maps were constructed at an original scale of 1:20,000 from all available data from the surveyed areas and are presented in the report. Computed thalweg slopes for the survey segments were generally flat or increased in elevation in a downstream direction, implying a tendency for the channel to shoal, especially in the Lake Providence and Greenville reaches. Regional geological structure, the lithology of Tertiary deposits underlying the Mississippi River, and alluvial deposits of variable erosion resistance in the flood-plain apparently hamper the river's ability to deepen its channel and to maintain sufficient flow velocity to prevent aggradation in the study reaches. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1983
- Accession Number
- ADA133099
Entities
People
- William L. Murphy