Surficial Sediments of Lake Erie

Publisher Website
Google Scholar
Abstract
On the basis of extensive echosounding and grab sampling, 3 major units were recognized in Lake Erie [Canada, USA]: till and bedrock, glaciolacustrine clay and postglacial muds. These units represent the late glacial and postglacial evolution of the basin and occur in an offshore younging sequence. The main basin of the lake is subdivided by residual glacial moraines into 4 depositional basins: western, Sandusky, central and eastern basins. The sediment texture has been defined by moment measures (mean, standard deviation, skewness and kurtosis), the trends of which are related to the mixing of 2 primary grain-size populations in the sand- and clay-size ranges. A 3rd grain-size mode in the silt size, composed of fine quartz with some carbonate, is recognized. This mode has a modifying effect on the symmetry of the 2 primary populations and may, to some extent, be sufficiently abundant to behave as a discrete population. The trends in the textural characteristics, particularly skewness and kurtosis, have been utilized to define energy regimes at the sediment-water interface which indicates 3 distinct sedimentary or hydraulic regions: western basin region .sbd. fine-grained sediment accretion in shallow water related to an imbalance in sediment budget, with high input loadings of fine-grained sediment, and deficit in coarse materials, with an excess of input over sediment export to the central basin region. This results in net sediment accretion in shallow water with texture in disequilibrium with environmental energy, which produces mixing and suspension, followed by redeposition; central basin region .sbd. W to E coarsening of sediment in textural equilibrium with hydraulic energy, as it relates to increasing fetch under westerly and southwesterly prevailing winds; eastern basin region .sbd. deepwater basin with sediments showing decreasing size offshore with increasing water depth. The deepwater sediment is modified by the influx of substantial quantities of the silt-size material derived from shoreline erosion in the N shore of the central basin region. The interrelationships of parameters indicate textural dependence on mineralogic composition, particularly important being the relationship of clay concentration to mean grain size. This has particular value in modeling the physical behavior of clay-associated geochemical elements such as P.

This publication has 7 references indexed in Scilit: