At some GRIP/GISP2 sites near the summit of Greenland, annual snow and ice layers can be traced back more than 40,000 years, similar to counting tree rings.
Notes on verification
Confirmed by multiple independent peer-reviewed and technical sources (GISP2, GICC05 studies) showing annual layer counting extending to 60,000-110,000 years, exceeding the claim's conservative 40,000-year figure. [tier=gold indep_score=0.963 clusters=4 claim_tier=notable]
Sources
- Greenland Ice-core Project/Greenland Ice Sheet Project 2 | geochronology | Britannica (seed:history_and_archaeology)
- https://www.academia.edu/20006997/Visual_stratigraphic_dating_of_the_GISP2_ice_core_Basis_reproducibility_and_application (corroboration)
- https://climatechange.umaine.edu/gisp2/data/ajgow.html (corroboration)
- https://cp.copernicus.org/articles/4/47/2008/ (corroboration)
- https://essd.copernicus.org/articles/15/3351/2023/ (corroboration)
- https://www.climate.gov/news-features/climate-tech/climate-core-how-scientists-study-ice-cores-reveal-earths-climate (corroboration)