MORPHOLOGICAL AND STRATIGRAPHIC ANALYSIS OF SEDIMENTARY DEPOSITS IN NEW SHARON, AND CHESTERVILLE, MAINE

A series of class-related field exercises for high school students was used for both educational development and to contribute to the understanding of poorly understood post-glacial features in west-central Maine. These features were investigated by mapping individual mounds with a global positioning system, determining sub-surface stratigraphy with ground penetrating radar, profiling the deposits, and conducting standard grain-size analysis on samples from representative deposits.

Evidence from this investigation indicates a single drumlin/till-tail feature at the south end of one study site. Its northwest/southeast orientation, elongated shape, and alignment with local striations suggest it was deposited during Laurentide ice advance. In addition, the identification of forty-two aeolian sand dunes in the same general area is supported by the combination of their location on the north and west sides of individual hills in the study area, generally northwest to southeast orientation, morphology, and grain-size distribution. Generally the dunes are longitudinal, and some also include parabolic features. As isostatic sea level lowered postglacially in the Sandy River Valley, glacial-marine and possible glacial-lacustrine deposits were exposed and subsequently transported by dominant northwest winds. These sediments were eventually redeposited as dunes at higher elevations on the north and west flank of local hills.