Paper No. 6
Presentation Time: 9:00 AM-6:30 PM

LATE-PLEISTOCENE WIND-FLOW PATTERNS AND DUNE FORMATION IN NORTH-CENTRAL LOWER MICHIGAN


ARBOGAST, Alan F.1, LUEHMANN, Michael D.1, MILLER, Bradley A.2 and WERNETTE, Phillipe A.3, (1)Department of Geography, Michigan State University, 673 Auditorium Road, East Lansing, MI 48824, (2)Department of Geography, Michigan State University, MSU Geography, 116 Geography Bldg, East Lansing, MI 48824-1117, (3)Department of Geography, Texas A&M, College Station, TX 77845, dunes@msu.edu

A variety of dune fields occur deep within the interior of Michigan. In contrast to the coastal dunes that have a well documented history spanning the past 5,000 years, the geomorphic history of Michigan’s interior dunes is poorly understood. These dunes presumably formed under different conditions than the modern coastal dunes, including deglacial scenarios of high sand supply and/or times of increased aridity and stronger winds. As a result, these landforms likely shed light on the paleoenvironmental history of the Great Lakes region and can be used to test models illustrating late-Quaternary atmospheric dynamics.

This study focuses on the geomorphic history of the Rosco dune field, which lies in north-central Lower Michigan. The dune field is about 23 km2 in size, lies immediately east of the Muskegon River, and contains a variety of parabolic dunes that have westerly orientations. In order to estimate the time of dune formation, 10 samples were collected for optical (OSL) dating. Ages indicate that the dunes formed ~ 11,000 years ago. This episode correlates with a period of dune formation in central Wisconsin and the development of spits in northeastern Lower Michigan associated with glacial Lake Algonquin. The spits formed from dominantly easterly winds and thus support modeled anticyclonic flow over the Laurentide Ice Sheet at that time. Given the close proximity (~100 miles) of the westerly-orientated Houghton dunes to these spits, this study supports the hypothesis that easterly winds were confined to a narrow zone along the ice front.