A century of change in the methods, data, and approaches to mapping glacial deposits in Michigan
William L. Blewett, David P. Lusch, Randall J. Schaetzl, and Scott A. Drzyzga
Mapping of glacial deposits in Michigan dates to the very beginnings of the glacial theory in North America and logically divides into three parts: (1) early work (1885–1924) by Frank Leverett, Frank Taylor, and their colleagues, culminating in U.S. Geological Survey Monograph 53 and the publication of the fi rst surfi cial geology maps for the state; (2) incremental upgrades (1925–1982) of Leverett and Taylor’s work in subsequent, statewide maps by Helen Martin and William Farrand; and (3) the period since 1982, characterized by a relatively small number of detailed, process-oriented studies at various scales, including the STATEMAP and EDMAP projects and investigations led by university researchers. Progress in mapping the surfi cial geology of Michigan has been challenged by the complexity of glacial deposits and limited state and federal funding. The most recent maps are Farrand’s statewide maps of glacial geology, which are based on the maps of Martin, which, in turn, were based on the original reconnaissance maps by Leverett and Taylor, now more than a century old. Thus, statewide maps of surfi cial sediments and landforms in Michigan are outmoded, often inaccurate, and in need of revision. Fortunately, new technologies and data sets are revolutionizing traditional mapping methods, creating opportunities for making cost-effective and accurate maps of Michigan’s glacial deposits. Digital soils data, in particular, when viewed within a geographic information system environment, offer an especially promising avenue for improved glacial mapping.