Master of Science (MS)
Geology and Geophysics
Optically stimulated luminescence dates coupled with paleohydrological estimations from lower Mississippi River (LMR) meander belts within the Yazoo Basin, MS provide new insight into the geochronological and hydrologic history of the LMR throughout the Holocene period. According to OSL dates, there are only three temporally equivalent LMR meandering river regime sediment packages, and not five as previously assumed from past geochronological research initiatives within the lower Mississippi Valley (LMV). The three geochronological sediment packages from oldest to youngest are thus represented by the following LMR meander belts: Early Holocene Chronostratigraphic Package – ca. 9.19 to 8.07 ka represented by the Stage 5 LMR meander belt (MB 5), Middle Holocene Chronostratigraphic Package – ca. 7.85 to 4.5-4.2 ka represented by the Stage 3 and Stage 4 LMR meander belts (MB 3 and MB 4), and Late Holocene Chronostratigraphic Package – ca. 4.5-4.2 ka to present represented by the Stage 1 and Stage 2 LMR meander belts (MB 1 and MB 2). Furthermore, paleohydrological estimations constrained by OSL dates suggest that by ca. 9.19 to 8.07 ka the LMR had transitioned from a braided river regime to a meandering river regime within the Yazoo Basin, MS where the average bank-full discharge (AvgQbf) of the single active channel (MB 5) was equivalent to ~ 47, 000 m3/sec. From ~ ca. 6.96 to 4.5-4.2 ka, the LMR split its total available discharge between two active channels (MB 3 and MB 4) in an approximate 50:50 ratio whose combined bank-full discharge was equivalent to ~ 34,900 m3/sec. The LMR also split its total available discharge between two active channels (MB 1 and MB 2) for an interpreted short period of time after ca. 4.5 ka where the estimated AvgQbf of MB 2 was equivalent to ~ 10,500 m3/sec representing ~ 32% of the calculated average bank-full discharge of the modern LMR between Memphis, TN and Vicksburg, MS.
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Prokocki, Eric, "Holocene Evolution and Avulsion History of the Lower Mississippi River, Yazoo Basin, MS" (2009). LSU Master's Theses. 2070.
Summers, Annette Engel