Duration of Greenland Stadial 22 Andice-Gas ∆age from Counting of Annuallayers in Greenland NGRIP Ice Core
The NorthGRIP ice core chronology GICC05modelext is composed of the annual-layercounted GICC05 chronology to 60 kyr before 2000 AD (b2k), and an ice flow model dating the deepest part of the ice core to 123 kyr b2k. Determination of annual strata in ice5 beyond 60 kyr b2k has been challenged by the thinning of annual layers to < 1 cm andthe appearance of microfolds in some early glacial strata.