THREE DIMENSIONAL GEOMETRY OF A LATE-PLEISTOCENE BASIN, HYDE PARK, NEW YORK, INTEGRATING FIELD OBSERVATION TECHNIQUES AND GROUND PENETRATING RADAR

During August and September 2000, detailed stratigraphic information was extracted from a pond in Hyde Park, New York, containing the near complete remains of an adult American Mastodon (Mammut americanum). Several trenches and cores at various locations throughout the basin show a depositional sequence typical of temperate postglacial lakes. The top of the stratigraphic section is represented by coarse detrital peat, a thickness of which cannot be determined due to modern disturbance of the landscape. This peat grades into a transition zone consisting of a humic, carbonate-rich silty clay. It is within this layer that the majority of the mastodon remains were uncovered. Below this horizon is located a uniform, humic silty marl, with laminations visible at the base of this zone. This is followed by a massive clay characterized by the occasional subrounded cobble suspended within the matrix. This entire sequence rests upon cobbles and gravel of the Hyde Park Moraine. Each of these horizons is present at every location sampled, though the thickness of individual units and the character of the contacts between these units does vary. This data, in conjunction with information recovered using ground penetrating radar (GPR), has allowed us to reconstruct the profile of this symmetrical basin. An accurate representation of the basinal geometry, in conjunction with the ongoing analyses of fossil-rich sediments collected from various positions within the basin, will allow us to better understand the complexities of microenvironments found within this site, and will be useful as an analogue for similar sites in the future.