An enduring problem in North American archaeology concerns the nature of the transition between the Clovis and Folsom Paleoindian complexes in the West. Traditional models indicate a temporal hiatus between the two complexes implying that Folsom was a population replacement for Clovis. Alternatively, if Folsom was an innovation that occurred within Clovis populations and subsequently spread, we would expect to see a temporal overlap. Here, we test these hypotheses using high-quality radiocarbon dates and Bayesian statistics to infer the temporal boundaries of the complexes. We show that the Folsom complex initially appears between 12,900 and 12,740 cal BP, whereas Clovis disappears between 12,720 and12,490 cal BP. Therefore, Folsom may have appeared about 200 years before Clovis disappeared, and so the two complexes likely co-occurred in the West for nearly eight generations. This finding suggests that Folsom was a successful adaptive innovation that diffused through the western Clovis population, eventually going to fixation over multiple generations.

北美考古学中一个长期存在的问题涉及西部克洛维斯和福尔松古印第安人复合体之间过渡的性质。传统模型表明两个复合体之间存在时间中断，这意味着 Folsom 是克洛维斯的人口替代品。或者，如果 Folsom 是发生在克洛维斯人群中并随后传播的创新，我们预计会看到时间重叠。在这里，我们使用高质量的放射性碳日期和贝叶斯统计来检验这些假设，以推断复合物的时间边界。我们发现 Folsom 复合体最初出现在12,900到12,740 cal BP之间，而 Clovis 在12,720到12,490 cal BP之间消失. 因此，福尔瑟姆可能在克洛维斯消失前约 200 年出现，因此这两个复合体很可能在西方同时出现了近八代。这一发现表明，Folsom 是一种成功的适应性创新，它在西部克洛维斯人群中传播开来，最终在多代人中被固定下来。