LATE QUATERNARY TEMPORAL AND EVENT CLASSIFICATIONS, GREAT-LAKES REGION, NORTH-AMERICA

Several temporal and event classifications are used for the Quaternary glacial and interglacial record in the Great Lakes region of North Am erica, Although based on contrasting principles, the classifications, as practiced, are similar to one another in most respects and they dif fer little from the classification proposed by Chamberlin a century ag o, All are based on stratigraphic units having time-transgressive boun daries; thus the associated time spans and events are diachronous. Whe re application of geochronologic classification based on isochronous b oundaries is not practical or useful, we advocate the use of diachroni c principles to establish local and regional temporal and event classi fications, Diachronic and event classifications based on such principl es are proposed herein for the Great Lakes region, Well-established na mes, including Wisconsin, Sangamon, and Illinois, are used at the epis ode (or glaciation/interglaciation) rank without significant redefinit ion, The Hudson Episode (Interglaciation) is introduced for postglacia l time, the current interglacial interval, The Wisconsin Episode is di vided into the Ontario, Elgin, and Michigan Subepisodes in the eastern and northern parts of the Great Lakes region and into the Athens and Michigan Subepisodes in the southern and western parts of the Great La kes region. (C) 1997 University of Washington.