Date of Award
Doctor of Philosophy
Dr. Alan E. Kehew
Dr. William Sauck
Dr. William Harrison III
Dr. Timothy Fisher
Southern Michigan's geomorphology is a testament to the glacial processes that buried and sculpted the landscape during the last glaciation. Many glacial landforms in southwestern Michigan, including the Kalamazoo River Valley, provide evidence that aids in understanding the chronology, ice dynamics and glacial processes that occurred in Michigan during the last ice age.
As the climate began to warm about 20,000 yr B.P. (Larson and Schaetzl, 2001) the extensive Laurentide Ice Sheet began to recede from its maximum southern position reached during the Late Wisconsinan (Figure 1). It was at this point that modem surficial drainage systems began to establish themselves beyond the ice margin. With climatic warming the ice sheet thinned and gradually became distinctly lobate, replicating the shape o f the Great Lake Basins into which ice-lobe flow lines converged (Zumberge, 1960; Kehew et al., 1999). The formation of three distinct lobes o f ice (Figure 1) began shaping southern Michigan’s topography and drainage routes. These lobes of ice formed a large interlobate region bounded by ice on three sides (Figure 1). Many drainage systems, including the Kalamazoo River, were established at this time through the release o f copious amounts of glacial meltwater followed by non-glacial runoff.
The Kalamazoo River and its many tributaries form a large modem drainage basin in the southern portion o f the state (Figure 2) that integrates drainage from several former ice lobes. While the ice continued to retreat in south-central Michigan, it occasionally paused or readvanced to form a series of uplands interpreted as recessional end moraines (Figure 3) (Leverett and Taylor, 1915; see Fisher and Taylor, 2002 for an alternate explanation). Here the term moraine is used in the non-genetic sense to indicate uplands formerly mapped as an ice marginal position. The term upland will be used to denote elevated terrain that displays sediments or landforms inconsistent with an ice marginal position.
Recently, evidence has been presented to suggest non-synchronous overlapping oscillations o f the Lake Michigan and Saginaw Lobes (Figure 2) occurred (Kehew et al., 1999). These oscillations resulted in an extremely complex landscape that make interpretations of stratigraphy and glacial chronology difficult.
Kozlowski, Andrew, "Origin of the Central Kalamazoo River Valley, Southwestern Michigan, USA" (2004). Dissertations. 3402.