Paper No. 9
Presentation Time: 1:30 PM-5:30 PM
COMPOSITIONAL AND TEXTURAL CHARACTERIZATION OF BOTTOM SEDIMENTS FROM THE LOWER CONNECTICUT RIVER, CONNECTICUT
While sediment transport has been well documented in the upper and lower estuary of the Connecticut River, this study attempts to characterize the textural and compositional trends of bottom sediments spanning the length of the lower Connecticut River, Connecticut. Samples were collected from the upper estuary (nine km from the mouth of the Long Island Sound (LIS)), the meandering section near Glastonbury (66 km from LIS), and the straight section northeast of Hartford (85 km from LIS). Analysis of the samples using X-ray diffraction and microscopy yielded an unexpected lack of textural trends- the sediments from all three localities had the same grain size distribution between -.5-1φ and similar roundedness between subangular-subrounded. This is opposed to the notion that grain size decreases with length of travel. Using a modified mineralogical maturity index, the sediments proximal to the LIS are classified as slightly more mature than distal sediments. Results indicate a medium energy fluvial environment pervades the tidal river and stretches into the boundary of the upper estuary with the estuary receiving coarse sediment from the tidal river. As well, the presence of characteristically metamorphic minerals in the sediments implies a metamorphic host source either from the Bronson Hill Belt or New Hampshire-Maine Sequence. The sediment textural and compositional distribution within the lower Connecticut River points to a possible sediment source closer to the terminal end of the river than the expected source near the headwaters in Canada.