HR: 1330h
AN: NS23B-10    [Abstracts]
TI: Subsurface Investigation of the Internal Architecture of Massawepie Esker-Mire Complex, Gale, New York
AU: Rupp, J R
EM: jrrupp01@stlawu.edu
AF: Geology Department St. Lawrence University, St. Lawrence University, Canton, NY 13617 United States
AU: * Davis, J L
EM: jldavi01@stlawu.edu
AF: Geology Department St. Lawrence University, St. Lawrence University, Canton, NY 13617 United States
AU: Robinson, S D
EM: srobinson@stlawu.edu
AF: Geology Department St. Lawrence University, St. Lawrence University, Canton, NY 13617 United States
AB: The retreat of the Laurentide Ice Sheet from the Adirondack Highlands of northern New York approximately 12,500 yr. B.P. led to the development of a landscape marked by glaciofluvial landforms such as kames, outwash, kettles and eskers. The Gale, New York study site (44o 15'N, 74o38'W) contains a prominent esker approximately 30 m high that trends northeast/southwest for 12 km. A 364 ha ombrotrophic peatland underlain by outwash lies adjacent to the esker along a portion of its length. Ground Penetrating Radar (GPR) surveys were conducted on the esker and peatland areas, as well as at the contact between these landforms in an attempt to establish possible linkages between their environmental, developmental and topographic settings. Using 50 and 100 MHz antennas, the esker profiles yielded a signal penetration of approximately 20 m through primarily sand. Interpreted facies showed reflector beds of variable continuity indicative of both turbulent and laminar flow, chute and pool structures, erosional unconformities, random boulder distribution and diagenetic failure planes. On the peatland, the surveys were successful in mapping internal structure and development of the peat, and delineation of a relatively flat basal outwash unit dated at 5,600 yr. B.P. at approximately 3 m depth. The basal unit consists of medium to coarse grained sand, with discrete portions of the bed raised 2 m above the high amplitude basal reflectors suggesting possible channelization. The preliminary interpretation of a channelized base suggests that there is a link between the esker and peatland. The sinuous form of the infilled subglacial network suggests that the rise in the peatland base may be a remnant of an esker branch. This smaller remnant branch bounded by shallow stagnant ice depressions could create a landscape that would encourage peatland development. The peatland currently has three different floral zones showing different levels of wetland maturation possibly reflective of the basal topography.
DE: 0999 General or miscellaneous
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly