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Glaciated Karst Terrain in the Door Peninsula of Wisconsin 
Abstract. Glaciated kanst terrain, which is poorly documented in the United
States, is well developed in the Door Peninsula of northeastern Wisconsin.
The peninsula is a southeastwarddipping cuesta developed on the Silunian
Niagaran dolomite. Wisconsinan glacial plucking east of the escarpment produced
glaciokanst features including alternating steps and risers (schichttreppenkarst)
and extensive dolomite pavements. Pre- and post-glacial karst landfonms include
enlarged crevices (gnikes), sinkholes, and caves. Staircases and pavements
are predominantly south- and east-facing and are particularly well developed
on the Brussels Hill outlien. Their distribution is as predicted by the general
model of northwest-southeast ice movement. Many of the smaller kanst landfonms
are postglacial, although shallow features may have an important inherited
component, and the larger sinkholes and the caves may antedate Wisconsinan
glaciation. Much of the postglacial karst development is in the Burnt Bluff
Formation on the western side of the peninsula where the hydraulic gradient
is steepest, joints ane dilated, and the drift is thinnest. Regional joint
sets at 25, 70, and 155 degrees have strongly influenced cave and sinkhole
development. 
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Carol J. Rosen and Michael J. Day 
Although large areas of carbonate bedrock in the United States experienced
the effects of Pleistocene glaciation, glaciokarst—characteristic
terrain
developed through glaciation of karst landscape—is poorly documented.
In many areas glaciokarst is limited because the himestones or dolomites
are mantled by thick, often carbonate-rich glacial deposits. These mask any
preglacial karst, as well as the effects of glacial erosion, and hinder postglacial
karst development. Never- 
Carol Rosen is an Assistant Professor of Geography at 
UW-Whitewater. She received her PhD from UWMilwaukee in May, 1990. Her MS
Thesis at UWMilwaukee dealt with the Karst geomorphology of the 
Door Peninsula. 
Michael Day is an Associate Professor of Geography at UW-Milwaukee. His research
focuses on karst geomorphology. He received the DPhil from Oxford University
in 1978. 
theless, glaciokarst is present in some areas, particularly where drift deposits
are thin. In this paper we call attention to one major area of glaciated
karst terrain developed on dolomites in northeastern Wisconsin and present
some initial results of studies of the karst landforms. 
The Regional Setting 
 The Door Peninsula, which extends some 100 km into Lake Michigan and ranges
from 
5 to 30 km wide (Fig. 1), is a cuesta developed on the Silurian-aged Niagaran
dolomite (Sherrill 1978). The Niagaran Series is approximately 107-m thick
and consists dominantly of light gray, medium to coarsegrained, thin-bedded,
fossiliferous dolomites. Bioherms are common and are expressed topographically
in outliers such as Brussels Hill, the highest point on the peninsula at
260 m (Thwaites and Bertrand 1957).