Fluted Points and Geochronology of the Lake Michigan Basin

Autor: George I. Quimby
Rok vydání: 1958
Předmět:
Zdroj: American Antiquity. 23:247-254
ISSN: 2325-5064
0002-7316
DOI: 10.2307/276306
Popis: FLUTED projectile points of chipped flint have been found occasionally in Michigan and Wisconsin. Most, if not all of these, closely resemble the Clovis style of fluted point found in the west. There is some evidence indicating that the western Clovis points belong to a period older than 8000 B.C. A number of archaeologists, myself included, have assumed that the eastern varieties of fluted points are of approximately the same order of antiquity as the western points. In the upper Great Lakes region it is possible to make a correlation between the distribution of fluted points and glacial events (Griffin 1956) showing that fluted points in general must postdate the maximum of the Cary glaciation. But only in the Lake Michigan basin area is it now possible to make more specific correlations between late Pleistocene surface features and fluted point finds. Because of lack of geological data and differences of interpretation of the same data by well qualified geologists, there is no single geochronology of pre-Lake Algonquin stage events that can now be applied accurately to the entire upper Great Lakes area. The situation is even worse with regard to correlations between the upper and lower Great Lakes. Only in the Lake Michigan basin is there a reasonably well-established geochronology of geological events that can be combined with a reasonable number of radiocarbon dates. It is my purpose here to attempt a correlation between certain loci of fluted point finds and specific surface features stratigraphically fixed in the geochronology of the Lake Michigan basin. Since this approach depends upon the distribution of late Pleistocene surface formations related to glacial advances and retreats and to specific lake levels it can be applied only to an exceedingly restricted geographic area within the Lake Michigan basin. And this geographic restriction automatically excludes from consideration the vast majority of the fluted blade finds in the upper Great Lakes area. Despite the large area excluded, I have 6 possibly significant loci, three in northeastern Wisconsin and three in western Michigan. For purposes of this study I have assumed th t the fluted points were deposited by paleoIndians. It is immaterial that subsequently they may have been moved by wind or water so long as the movement was local. I have further assumed that the geochronology and radiocarbon dates used are essentially correct. Geochronology of Lake Michigan Basin. A brief outline of late glacial and postglacial events in the Lake Michigan basin is as follows: The Cary glaciation includes all morainic systems in the Lake Michigan basin from the Minooka moraine (earliest Cary) to the Port Huron moraine (latest Cary). In late Cary times, first the Lake Border morainic system and later the Port Huron moraine (Fig. 2) were correlatives of the Glenwood stage of Lake Chicago, a glacial lake with a water plane 640 feet above present sea level (Zumberge 1956: 3-4). In the vicinity of Whitehall, Michigan, the Glenwood Lake plain disappears under the later Valders deposits, presumably ending in contact with Port Huron deposits that also are overlain by Valders drift. Some radiocarbon dates of different Glenwood deposits are (W-140) 10,695 B.C. and (W-161) 10,245 B.C. (Rubin and Suess 1955: 483). One radiocarbon date (Y-147X) 9985 B.C. probably dates an oscillation in the retreat of the Port Huron moraine in northeastern Wisconsin. This date is from a log "transported by the ice that deposited gray till" (Preston, Person, and Deevey 1955: 958). The gray till in this area is Port Huron till. Some time after about 10,000 B.C. the Port Huron ice front retreated to a position north of the Straits of Mackinac and the water plane in the Lake Michigan basin dropped to 580 feet above present sea level and perhaps some hundreds of feet lower, depending on availability of eastern outlets. This is the Bowmanville low water stage (Fig. 3) named by Baker (1920: 69) for a type locality in north Chicago. However, in the absence of radiocarbon dates, it is possible that some low water stage other than Bowmanville is indicated by some deposits in the Bowmanville locality. In any case the termination of the Bowmanville low water
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