Northeastern (46th Annual) and North-Central (45th Annual) Joint Meeting (20–22 March 2011)

Paper No. 9
Presentation Time: 1:30 PM-5:30 PM


ROMERO, Gabriel A., Pomona College, 185 East Sixth Street, Claremont, CA 91711, GAINES, Robert R., Geology, Pomona College, 185 East 6th Street Claremont, Claremont, CA 91711 and O'CONNELL, Suzanne, Earth and Environmental Sciences, Wesleyan University, 265 Church Street, Middletown, CT 06459,

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.