An Alaskan ridge above the Tanana River yields three Ice Age occupations spanning 1,100 years

The three dates are unevenly spaced. The oldest component is 800 years older than the middle one ^[14], and the middle one is 300 years older than the youngest ^[15]. The span is 1,100 years ^[16]. Phys.org's account has the land bridge going under rising seas around 12,000 years ago ^[8]. The youngest component is about 700 years older than that date ^[17].

The paper's title attaches the words "base camp" to the 13,800-year occupation ^[2]. The finds in the press account come from several seasons of work. Kelly Graf, who directs the project, first made the trek in 2013, visited every year until the pandemic, and returned in 2021, 2023 and 2025 ^[9]. Together they total more than 80,000 specimens ^[5]. The account describes the dwelling feature, the oven and the activity areas without saying which component each belongs to, so the base-camp label cannot be checked against the layer it names from this text alone.

Bone processing is an inference from association. The anvil, the hammerstones and the bison bones lay together in a dwelling feature next to the oven ^[6]. Graf hedges her own reading: "So we think they were using these stones to fully process the bones to extract marrow and likely to render grease," she said ^[7].

The points carry the cross-Bering argument. Graf said they are numerous and were perhaps the sharpened tips of weapons ^[13]. "It suggests people traveled across the Bering Land Bridge to and possibly from this location," she said ^[19]. The thing this doesn't tell you is direction. A shared shape ties two regions together but does not show who moved first. Graf's wording is firmer about travel to the site than from it.

What the features do support is a stay of some length. A dwelling feature, a large earth oven and well-preserved activity areas all fit it ^[6][5], though the duration is our inference from the features. Needles made from bird bone were found too ^[11].