POSSIBLE EVIDENCE OF RELICT POLYGONAL GROUND FEATURES IN THE FINGER LAKES REGION OF NEW YORK: A PILOT STUDY USING GOOGLE EARTH PRO

Relict polygonal ground (RPG) are soil-geomorphic features that formed during past cold-climate, deep frost or permafrost, conditions. In the Great Lakes region, RPGs are increasingly recognized on deglaciated landscapes of Indiana, Ohio, Michigan, and Wisconsin. In contrast, RPGs are not reported for New York state despite other evidence of periglacial conditions during the late Pleistocene. This pilot study used geographic information systems, primarily Google Earth Pro, to review high-resolution aerial images between the years 2005 and 2016 in three New York counties in the Finger Lakes region: Seneca, Schuyler, and Tompkins. This study identified 52 potential RPG clusters across ~31 km² of primarily agricultural land between N42.3°and N42.8° latitude. This finding confirms the presence of RPGs in New York, north of the LGM margin. Observed RPGs are rounded to curvilinear, dark outlined, interlocking nests of polygons of variable size. RPG visibility varies between image years and ground cover conditions. Direct age control is absent, but RPGs likely formed between 17.5 and 14.7 ka cal yr BP based on radiocarbon dating of the Outer Valley Heads and Mapleton moraines which formed during the Port Bruce and Port Huron Stadials, respectively. A dense concentration of RPGs immediately south of, and largely paralleling, the Inner Valley Heads morainal system dated to 15.8 ka cal yr BP may indicate a temporal association for many of these features. The recovery of Dryas fossils in basal cores of Dumond Lake dating to 12.6 ka cal yr BP, however, potentially suggest a late persistence of permafrost conditions in the region. Expansion of this pilot study is planned in the coming years and will include ground truthing of select RPG targets and continued review of additional counties along a roughly north-south transect across New York.