Teresa Wriston
|
| Figure 1: Map of Oregon and location of Weed Lake Ditch site. |
|
| Figure 2: Gravel spit upon which the Weed Lake Ditch site is located. |
The Weed Lake Ditch site is a buried and stratified stemmed point site that likely dates to the early Holocene, 10,000-8,000 years ago. The site is located in the Harney Lake basin, southeast Oregon (Figure 1). The early Holocene cultural stratum overlies a gravel beach bar created during the last highstand of pluvial Lake Malheur (Figure 2). In the 1980s, Keith Gehr (1980) tentatively dated this highstand to about 8680 years ago.
Sundance-sponsored field research at the site was initiated in summer 2000 after a Haskett stemmed projectile point was discovered in situ in a drainage ditch exposure (Figures 3, 4). Excavation of two 1x1-m test units, undertaken by the Sundance field crew, resulted in the recovery of 18 stone tools (Figure 6), 2018 pieces of lithic debitage, 2166 bone fragments, and numerous examples of shells and seeds, all from a single stratigraphic layer. Although the random vertical and horizontal distributions of both gravels (which comprise approximately 30-40% of the stratum) and artifacts indicate that bioturbation has significantly affected the cultural stratum, integrity of the deposit (from which artifacts representing the entire range of lithic reduction have been recovered) is more than sufficient to reconstruct environmental conditions and human activities during cultural occupation of the site.
 |
 |
| Figure 3: Haskett point fragment found eroding from ditch in 2000. | Figure 4: Fred Nials examining Haskett point in situ (red arrow points to artifact). |
During summer 2001 investigations at Weed Lake Ditch continued with two goals. First, we hoped to increase the sample of time-sensitive projectile points and other lithic artifacts to permit detailed reconstructions of the lithic technological activities that prehistoric hunter-gatherers carried out at the site. Second, we hoped to obtain organic samples for radiocarbon dating analysis (bone recovered in 2000 was too degraded to reliably date). This would allow us to directly date the cultural occupation and to test Gehr's original age estimate for the last highstand of the lake.
 |
 |
 |
| Figure 5: Weed Lake Ditch site excavation, 2001. | Figure 6: Bifaces from Weed Lake Ditch. | Figure 7: Bead blank. |
To this end, the Sundance field crew (1) excavated six 1x1-m squares adjacent to the drainage ditch (Figure 5), (2) conducted an intensive surface survey of the site area, and (3) excavated four backhoe trenches near the margin of the embayment to expose detailed stratigraphic profiles. Excavations resulted in the discovery of one possible bone bead "blank" (Figure 7), three stemmed projectile points, eight other stone tools, 13 charcoal samples, and numerous pieces of bone and lithic debitage. Analyses of these materials are ongoing.
 |
| Figure 8: Did the environments of the early Holocene look like this? |
|
| Figure 9: Scott Thomas hauling buckets. |
The Weed Lake Ditch site is significant in that it contains a sealed Paleoarchaic occupation associated with the last highstand of pluvial Lake Malheur. In addition, charcoal obtained from the site's excavation can be used to date this occupation and highstand, thus allowing for more accurate environmental modeling by archaeologists and other scientists concerned with the past. Future Sundance research at Weed Lake Ditch will focus on continued analysis of the site's geomorphic and paleoecological context, the ultimate goal of which is reconstruction of early Holocene paleoenvironments and human adaptations (Figure 8).
Special thanks to Scott Thomas (Figure 9), Burns District Archaeologist, Bureau of Land Management, for supporting the Weed Lake Ditch project.
Gehr, Keith Donald
1980 Late Pleistocene and Recent Archaeology and Geomorphology of the South Shore of Harney Lake, Oregon. Unpublished Master's Thesis, Department of Anthropology, Portland State University