Abstract |
Phleger gravity cores were collected from three small reservoirs in Mississippi--USM Lake (7 cores), Lake Geiger (12 cores) and Lower Ross Barnett Reservoir (11 cores). Striking contrasts in color and grainsize permitted differentiation of reservoir sediment (dark green, nearly sand-free) from older and now-inundated soil (red, yellow, brown or grey muddy sand) in these cores. Range and average thickness of reservoir-accumlated sediment for 12-year-old USM Lake, 30-year-old Lake Geiger, and 11-year-old Ross Barnett Reservoir were, respectively, 55 to 342 mm, average 137 mm; 35 to 210 mm, average 93 mm; and 5 to 347 mm, average 58 mm. Average annual rate of sediment accumulation in USM Lake, Lake Geiger, and Lower Ross Barnett Reservoir was calculated to be, respectively, 9 mm/year, 3 mm/year, and 2.6 mm/year. Contrary to expectations, no sedimentary layering was discernible in split cores of these reservoir sediments. (Author) |