Ice-Free Corridor deglaciation and human passage evidence (c. 16,000–11,000 BP)

1. Ice sheets block the inland route south

   Jan 1, 24000 BCELabels: Laurentide Ice, Cordilleran Ice

   • PNAS bison
   • Cryosphere 2022

2. Bluefish Caves indicate Beringia presence

   Jan 1, 22000 BCELabels: Bluefish Caves, Yukon

   • PLOS ONE
   • Smithsonian

3. White Sands footprints show deep pre-Clovis presence

   Jan 1, 21000 BCELabels: White Sands, New Mexico

   • USGS 2021
   • USGS 2023

4. Cooper’s Ferry occupation predates corridor opening

   Jan 1, 14560 BCELabels: Cooper s, Idaho

   • Science PubMed
   • Smithsonian

5. Deglaciation begins to separate ice sheets

   Jan 1, 13850 BCELabels: Deglaciation, Laurentide Northwest

   • Cryosphere 2022
   • Cryosphere 2022

6. Paisley Caves strengthen pre-Clovis interior presence

   Jan 1, 12250 BCELabels: Paisley Caves, Oregon

   • UOregon
   • Science PubMed

7. Mackenzie Valley portion deglaciates, enabling a corridor

   Jan 1, 11650 BCELabels: Mackenzie Valley, Ice-Free Corridor

   • Cryosphere 2022

8. Bison dispersal indicates a habitable corridor by 13,000 cal BP

   Jan 1, 11050 BCELabels: Bison dispersal, Ancient DNA

   • PNAS bison

9. Clovis technology spreads after corridor viability

   Jan 1, 11000 BCELabels: Clovis, Clovis complex

   • Sci Adv 2020

10. Upward Sun River burials show established Beringian populations

    Jan 1, 9550 BCELabels: Upward Sun, Alaska

    • Smithsonian

11. Corridor becomes a two-way contact route in the late Pleistocene

    Jan 1, 9000 BCELabels: Ice-Free Corridor, Late Pleistocene

    • PNAS bison
    • Cryosphere 2022

12. Modern synthesis: early peopling predates corridor passage window

    Jan 1, 8750 BCELabels: Modern synthesis, Peopling models

    • Cryosphere 2022
    • Science PubMed
    • PNAS bison