Ushki-5, Kamchatka, and
the Peopling of the Americas

Preliminary Results of the Joint-Russian-American Expedition, 2000

Ted Goebel, Michael R. Waters, and Margarita Dikova

Introduction

Archaeologists have long looked to Siberia for clues about the origins of the first Americans. The traditional colonization model holds that humans migrated from Siberia to Alaska across the Bering Land Bridge, or "Beringia," the land mass that connected Asia to America during glacial episodes of the Pleistocene. To date, however, Siberia has not revealed a clear archaeological ancestor that resembles and predates Clovis, the earliest unequivocal culture in North America, dated to as early as 11,500 years ago.

One Siberian contender that has been largely overlooked is Ushki, a set of late Pleistocene sites located in central Kamchatka, far eastern Siberia (Figures 1, 2). These sites, excavated by the late Nikolai N. Dikov intermittently over the last three decades, have the potential to provide critical information about the Pleistocene peopling of Beringia and the Americas.

Figure 1: Map of Russia showing location of Ushki site.	Figure 2: View of Ushki Lake, Kliuchevskii Volcano and Ushki-5 site (in trees across lake). Photo taken from Ushki-5 site.

Two of these multi-component sites, Ushki-1 and Ushki-5, are dated to as early as 14,000 years ago and have produced a spectacular number and variety of artifacts, as well as dwelling features and faunal remains. Both Ushki-1 and Ushki-5 have two buried cultural levels that have been assigned to the late Pleistocene. Level VI has been dated to about 10,700 years ago, and contains a Diuktai-like wedge-shaped core and microblade industry. Level VII, the lowest of these levels, is dated to about 14,000 years ago and has produced a non-microblade lithic assemblage that is dominated by small bifacial points and flake tools. This assemblage, although only cursorily described, appears similar to the early Nenana Complex assemblages of central Alaska that are also microblade-free. In both cultural levels at Ushki-1, preserved dwelling features, hearths, and burials have been found. Despite their riches, these sites have been largely relegated to the status of footnote in recent reviews, such as West's (1996) recent synthesis in the book American Beginnings, due largely to the lack of detailed information about them, as well as questions concerning their integrity. Nonetheless, given their location, presumed age, and the reported character of their earliest artifact assemblages, the Ushki sites may hold answers to some of the most compelling issues in peopling of the Americas studies.

Figure 3: Ushki 2000 field crew.

In September-October 2000 we initiated a joint-Russian-American field research program at Ushki Lake. Our scientific research team included Ted Goebel, Margarita Dikova, Michael R. Waters, Ian Buvit, Kelly Graf, Irina Ponkratova, Igor' Sleptsov, and Karisa Terry (Figure 3). The focus of our Year 2000 research program was Ushki-5, a stratified site with two cultural components spanning the late Pleistocene-early Holocene period, 14,000 to 10,000 years ago. We decided to focus our attention on Ushki-5 for two reasons. First, much of Ushki-1's late Pleistocene deposits have been excavated, and all of the site's Holocene sediments were stripped away with a bulldozer during the 1970s. Second, Ushki-5 presented us with a chance to replicate the results of Dikov's excavations at Ushki-1, in that both of the late Pleistocene occupations, referred to by Dikov as level VII and level VI, had been previously identified through test excavations in the 1970s.

Ushki-5 Location and History

Ushki-5 is located along the southern shore of Ushki Lake, a large "oxbow" lake of the Kamchatka River. The site lies within a terrace of the Kamchatka River, the surface of which is only about 4 m above the modern level of the river.

Ushki-5 is situated along a low promontory or "cape" that juts northward into Ushki Lake. In the early 1970s Dikov excavated two large test pits along the western and eastern margins of the site, as well as a 1-m wide trench through the main part of the cape. In this cape a stemmed point was found, as was a large cobble thought to be part of a hearth. Last fall, our team opened up two excavations. The first was a 1x2 m test pit at the top of the cape. The goal of this excavation was to expose a complete stratigraphic profile of the Holocene and late Pleistocene deposits preserved at the site. The second was a 4x5 m excavation situated alongside Dikov's 1974 trench. The goal of this excavation was to expose a large area in order to investigate whether hearth or dwelling features were preserved in either of the late Pleistocene cultural levels. During our time at Ushki-5 last fall, water level in the lake reached one of its lowest points in recent history. Many Paleolithic artifacts were found exposed in the beach muds in front of the site, indicating that there has been significant recent erosion of the Ushki-5 site.

Figure 4: Mike Waters, Ian Buvit, and Kelly Graf in test pit.

Figure 5: Ushki-5 stratigraphic profile (upper 2 m).

Ushki-5 Geologic and Cultural Stratigraphy

Our 1x2 m test pit reached a depth of about 325 cm, and exposed a complete Holocene and late Pleistocene stratigraphic profile. We carefully excavated with trowels to pinpoint the context of preserved cultural levels and provenience of artifacts (Figure 4). In all, three cultural levels were preserved, which we have labeled levels IV, VI, and VII, based on comparisons of their stratigraphic provenience with Ushki-1. We also found a few artifacts that may indicate the presence of level V.

The upper 125 cm of the profile is dominated by the modern soil, a series of buried volcanic ash deposits, and several well-defined paleosols, or fossil soils (Figure 5). No cultural materials were found in this packet of sediments. About 130 cm below the surface, we exposed a very thick and well-developed paleosol that contained what appears to be a Neolithic stone tool industry, referred to here as cultural level IV. This buried soil horizon, called by Dikov the "Chornyi Gumus" [or black humus], is an obvious stratigraphic landmark in all of our profiles, and is dated to about 4,000 years ago at Ushki-1. Besides these artifacts, a storage pit and hearth were exposed. A second clear cultural level was identified at about 200 cm below the surface. This contained a small collection of microblades, a platform rejuvenation spall of a wedge-shaped core, and associated debitage. These occur in a silt to silty clay deposit that is stratigraphically consistent with Dikov's level VI at Ushki-1. Finally, two small stone beads very similar to those that Dikov found associated with a human burial in level VII at Ushki-1 were found at a depth of 260 cm below the surface, in a clay deposit. The stratigraphic context of these beads is again consistent with Dikov's placement of cultural level VII at Ushki-1.

Significantly, our findings in the Ushki-5 test pit have replicated the late Pleistocene geological and cultural stratigraphy presented by Dikov for Ushki-1. We have established that the late Pleistocene deposits at Ushki-5 and Ushki-1 are vertically accreting fluvial deposits that resulted from a series of flooding events of the Kamchatka River. We have confirmed that cultural levels VII and VI are separated by at least 30 cm of sterile sediment, including a 20-cm-thick layer of fining-upward silt and sand.

Our research program calls for a combination of radiocarbon and tephrochronological dating of the Ushki-5 and Ushki-1 sites. From the test pit at Ushki-5, we collected at least 40 samples of charcoal from the various stratigraphic layers. Some of these have been submitted to Stafford Laboratories and the Arizona Radiocarbon Laboratory for accelerator radiocarbon analysis. We still await final results.

Figure 6: Block excavation at Ushki-5.

Figure 7: Level VI hearth.

Figure 8: Karisa Terry excavating level VII hearth.

Figure 9: Stemmed points from level VII.

Block Excavation of Late Paleolithic Cultural Levels

Our 4x5 m excavation alongside Dikov's 1974 trench (Figure 6) yielded a dwelling feature complete with a lined hearth and post-hole moulds in level VI, as well as two unlined hearth features in level VII. The level VI dwelling was subterranean, and roughly 5-m in diameter. The floor of the dwelling was marked by a clearly defined floor of charcoal and other organic residue. The dwelling was dug into the ground to a depth of about 30 cm below the prehistoric ground surface. A distinct shoulder was traced around the entire perimeter of the dwelling, and a narrow "arctic entry" passage was noted in the northwest quadrant of the dwelling. Numerous lithic artifacts including microblades, wedge-shaped cores, and small leaf-shaped bifaces were found clustered near the hearth and around the perimeter of the dwelling. Most of these artifacts were manufactured either on chert, chalcedony, or obsidian.

The level VI hearth was situated near the center of the living space. It was about 80 cm in diameter and lined with large stones (Figure 7). There appear to be two episodes of burning in the hearth, both clearly defined stratigraphically. We collected two column samples of the hearth for microstratigraphic analysis, and collected flotation samples from each discernible level within the hearth. David Rhode of the Desert Research Institute floated these samples and recovered thousands of small fragments of bone, some of which appear to represent bird and fish (presumably salmon) remains. No bones were found outside the hearth feature, with the exception of a wet shadow of bone that could not be preserved or collected.

In level VII, two hearths were found (Figure 8). Both of these were unlined smears of charcoal, ash, and burnt bone fragments. They appear to have been dispersed somewhat, presumably due to low-energy flood-waters that covered the site soon after the level VII occupation. Lithic artifacts were dispersed across the living floor surrounding the two hearths, and the actual cultural level was less than 3 cm thick. In the center of the excavation, the level VII living floor had actually been disturbed by the later digging of the level VI house pit. Interestingly, several artifacts diagnostic of level VII (i.e., a stemmed point and chalcedony burin) were found in prehistoric backdirt that had been thrown outside the house pit during its construction.

The artifact assemblage we recovered from level VII included small stemmed bifacial points, small side scrapers, and retouched flakes (Figure 9). These were made on cherts, chalcedonies, and basalts; however, no obsidian tools or debitage were noted in our excavation of level VII.

Conclusions

In four weeks of field work at Ushki-5 and in our follow-up laboratory analyses, we have been able to answer some important questions about the Ushki Paleolithic sites. First, we have confirmed the presence of two late Pleistocene cultural levels, VI and VII. These two occupations are stratigraphically separated by more than 30 cm of sterile sediment, and appear to have been only minimally disturbed by post-depositional processes. In fact, there are no signs of cryoturbation at all in the site's sediments. Second, our excavations also produced numerous samples for radiocarbon dating, and soon we will be able to establish the chronometric ages of the Ushki Paleolithic levels. Third, we have also confirmed that cultural features are well-preserved in the site, and that microfaunal remains are preserved in hearths of both level VI and VII. Unfortunately, no larger faunal remains or macrobotanical remains were recovered. This seems to be the case for all of the Ushki sites. Finally, our excavations at Ushki-5 have yielded small but representative samples of lithic tools, cores, and debitage that can be used to define the cultural complexes represented in levels VI and VII. Level VI contains a clear wedge-shaped core and microblade industry with small leaf-shaped bifacial points. Level VII lacks microblades, and instead consists of stemmed bifacial points and small flake tools. There is clearly a technological and typological dichotomy between these two industries, and future studies will help define more specifically these differences, as well as perhaps finally explain why this variability exists.