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Whitford, Philip; Whitford, Kathryn (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume 74 (1986)

Keough, Janet R.
The Mink River- a freshwater estuary,   pp. 1-11 PDF (4.8 MB)


Page 2

2 Wisconsin Academy of Sciences, Arts and Letters [Vol. 74 
Fig. 1. Location of the Mink River on the Door County, Wisconsin, peninsula.
Rowley Bay of Lake Michigan (Figure 1). The watershed lies in Liberty Grove
Township (T32N, R28 and 29E). In this paper, I will describe the physical
setting of the Mink River wetlands and the vegetation types present and their
dynamic relationship with Lake Michigan. 
TOPOGRAPHY AND GEOLOGY 
Rowley Bay and the Mink River lie in a bedrock valley that extends across
the Door peninsula from Green Bay to Lake Michigan (Kowalke 1946). During
the Algonquin period, when the level of Lake Michigan was higher, the valley
formed a strait connecting Green Bay to Lake Michigan from Ellison Bay to
Rowley Bay. The underlying bedrock is Silurian Niagara dolomite; as elsewhere
in the Door Peninsula, this formation dips to the southeast, and forms the
primary aquifer. A wide portion of the river, "Rogers Lake," may
represent
a natural depression in the bedrock or an area eroded by the channel before
descending into Lake Michigan. Bedrock is within four feet of the surface
near Ellison Bay and outcrops in the upland around the Mink River. The upland
is covered by Pleistocene drift and shoreline deposits. Most of the region
was inundated 
by post-Pleistocene stages of Lake Michigan, resulting in permeable deposits
of sand and gravel along the west side of the river (Sherrill 1978). Thwaites
and Bertrand (1957) and Kowalke (1946) suggested that the uplands to the
northeast and southwest of the river were islands in Lake Algonquin, a higher
stage of Lake Michigan. A shoreline formed by Glacial Lake Algonquin (11,000-12,000
yr BP) has been found along Rowley Bay in Newport State Park at approximately
75 feet above present lake level. A Glacial Lake Nipissing shoreline (3,500-6,000
yr BP) occurs 21 feet above present level (Frelich 1979, Dorr and Eschmann
1977). The ancient beach ridges evident in the landscape around Rowley Bay
were Lake Nipissing beaches. The marsh along the Mink River is underlain
by alluvia! fine sand, silt and clay and organic material. 
Fig. 2. Topography of the area surrounding the Mink River. Contour interval
is 10 feet. Stippled areas represent open water and lakeshore boundaries.


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