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Gee Creek Archaeological Sites - Chronology

Radiocarbon Dates

The Gee Creek sites were dated by using AMS Radiocarbon Dating techniques on charcoal taken from some of the oven features found at the sites.

Charcoal from 10 of the oven features from the Gee Creek sites were submitted for radiocarbon dating. The distribution of the radiocarbon dated features through time is depicted in the figure to the right.

The dates indicate use of the sites throughout much of the Holocene (post-glacial) period from about 8,000 years ago to approximately 500 years ago. The sample of radiocarbon dates is too small to determine whether people used the area continuously or periodically during this long span of time. In either case, the uses appear to be for the same purposes, involving cooking or processing of food resources available in the immediate vicinity of the sites.
Radiocarbon chronology for Gee Creek sites
Radiocarbon chronology for Gee Creek sites Click here for larger image

The cultural periods shown on this map refer to cultural chronologies proposed for the Gee Creek vicinity in the archaeological literature.
For more on the cultural context of the Gee Creek sites, see the
Settlement section of this website.

Obsidian Hydration Dating

Two obsidian artifacts from the Gee Creek sites were sampled for obsidian hydration dating. Both artifacts were flakes -- byproducts of obsidian tool manufacturing. A formula used to calculate the ages of these obsidian hydration rinds resulted in estimates of 560 years old and 640 years old for the two flakes.

The hydration rinds on two obsidian flakes found at the Gee Creek sites measured 1.5 microns thick and 1.6 microns thick. Interestingly, one of the flakes also had a second, thicker and more diffuse hydration rind. The thickness of the second rind was measured at 5.8 microns which corresponds to an approximate age of 8,410 years old. This second rind may indicate that the people at Gee Creek reused an older artifact, in fact, one that was thousands of years older. Such reuse of older artifacts appears to have been fairly common and shows that the concepts of recycling and reuse are not new. Ancient Native Americans also recycled and reused materials.

Artifact Types and Cross-dating

Artifact types also changed over time. Like the historical changes we can observe in housing or modes of transportation, prehistoric artifact types also changed through technological developments, and stylistic evolution. The types of artifacts found at the Gee Creek sites are generally characteristic of artifacts found at other archaeological sites in the region that date to the early Holocene period from about 8,000 years ago to 4,500 years ago. The fact that these types seem to persist into more recent times at the Gee Creek sites suggests similar types of activities were being performed with similar types of tools through time. The similarities in artifact technology may relate to the specific task function of these sites for food processing. Just as certain aspects of modern society are slow to change, some aspects of ancient society also changed slowly.

Lanceolate projectile points   

Lanceolate projectile points (above) and cobble chopper (below) typical of early Holocene artifact assemblages

Cobble chopper


The information provided on this website is modified from the manuscript Archaeological Data Recovery for the I-5/SR 502 Interchange Project, by Michele Punke, Terry Ozbun, Jo Reese, and Brian Buchanan (2009).  Archaeological Investigations Northwest, Inc. Report No. 2273.  Prepared for Washington Department of Transportation Southwest Region, Vancouver, Washington.