Archaeological site interpretation can be enhanced by consideration of related geological and geomorphological processes. Lake Superior has a history of glaciation, isostatic recovery, and water-level change. Two examples are given of shoreline sites at which interpretation is enhanced by an understanding of local geologic factors. The archaeologic history of the Lake Superior basin is reviewed, and three cultural traditions are recognized; (1) Paleoindian, (2) Archaic, and (3) Woodland. Three significant factors ofgeologic history are then discussed: (1) ice margin oscillation, (2) differential isostatic uplift, and (3) lake-level fluctuations. The factors reducing o r improving shoreline archaeological site preservation are examined, and a summary model of shoreline site distribution for the Lake Superior basin is offered. It is concluded that the north shore provides the best potential for a complete archaeological record. 8 1993 John Wiley & Sons, Inc.
PROLOGUEIt is of concern to many geologists and geomorphologists who approach archaeology in their work, that incomplete or erroneous interpretation of archaeological sites sometimes comes about through insufficient attention to the "geologic filter," that is, the set of geological processes acting on the site and the context in which they took place. The object of pointing out the potential for misinterpretation is not to criticize the existing skills of the archaeologist, but to demonstrate that archaeological interpretation, both at local and regional scales, can be enhanced by more adequate consideration of geologic and geomorphic processes.Lake shorelines are biologically productive zones, particularly where sheltered embayments, marshes, and river mouths occur, and it is in these locations that prehistoric peoples have tended to concentrate their activities. The shoreline of Lake Superior, 82,103 km2 in area, is for the greater part comprised of rugged rock shores, such that bayhead beaches, marshlands, and river mouths are particularly important as potential habitation sites. Because of glaciation and isostatic uplift, Lake Superior is rimmed by the remains of strandlines of former post-glacial lakes occupying the basin, and it is on these that much of the evidence for prehistoric occupation has been found. SHORELINE SITE MODEL, LAKE SUPERIOR 50. 90 85 I I NORMERN ON 90 85 Figure 1. The Lake Superior basin-location map.-50 of these shoreline related sites has been closely linked to the succession of strandlines, which in places descend to present lake level in a staircase of lakeshore terraces . Larsen (1985), in a study of Lakes Michigan and Huron, warns that past approaches t o geological and archaeological studies of those lakes has shown that archaeological interpretation has been too closely tied to the current interpretation of post-glacial chronology, and that the interpretation of coastal landforms has relied more on surficial studies than on subsurface stratigraphical relationships (p. 96). The glacial and post-glacial history of the Superior ba...