Surficial Geology of the Picture Rocks 7.5-Minute Quadrangle;Open file rept

摘要

The Picture Rocks 1:24,000-scale detailed reconnaissance surficial geology map (map of unconsolidated materials overlying consolidated bedrock) was produced in four phases. In the first phase, a preliminary surficial deposit map was made using soil mapping (Grubb, 1986, Kohler, 1986), surficial deposit mapping along the late Wisconsinan border (Lewis, 1884$ Leverett, 1934$ Denny and Lyford, 1963$ Crowl and Sevon, 1980$ Cenderelli, 1989), bedrock mapping (Sevon, 1978), and landform analysis using the 1:24,000-scale topographic map and aerial photographs. In the second phase, the preliminary surficial deposit map was verified and/or corrected during twenty person-days or so of fieldwork. In the third phase, the field verified/corrected preliminary surficial geology map was finalized, drafted onto four mylar overlays (contacts, isochores, labels - rock outcrops, and glacial borders - striations - sluiceways), and had a text added. In the fourth phase, Thomas G. Whitfield of the Bureau of Topographic and Geologic Survey digitized the mylars and completed the digital map and produced ten final digital files$ geologic contacts, surficial deposit isochors, bedrock outcrops, sluiceways, slumps, striations, till mounds, a Wisconsinan terminus by Braun, a Wisconsinan terminus by Crowl and Sevon, and selected water wells.