Radiocarbon measurements at ice margin sites and blue ice areas can potentially be used for ice dating, ablation rate estimates and paleoclimatic reconstructions. Part of the measured signal comes from in situ cosmogenic ¹⁴C production in ice, and this component must be well understood before useful information can be extracted...
The cause of warming in the Southern Hemisphere during the most recent deglaciation remains a matter of debate[superscript 1,2]. Hypotheses for a Northern Hemisphere trigger, through oceanic redistributions of heat, are based in part on the abrupt onset of warming seen in East Antarctic ice cores and dated to 18,000...
The last glacial period exhibited abrupt Dansgaard–Oeschger climatic oscillations, evidence of which is preserved in a variety of Northern Hemisphere palaeoclimate archives¹. Ice cores show that Antarctica cooled during the warm phases of the Greenland Dansgaard–Oeschger cycle and vice versa[superscript 2,3], suggesting an interhemispheric redistribution of heat through a mechanism...
The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation
deep ice core that provides Antarctic climate records of
the past ~68 ka at unprecedented temporal resolution. The
upper 2850 m (back to 31.2 ka BP) have been dated using
annual-layer counting. Here we...
The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation
deep ice core that provides Antarctic climate records of
the past ~68 ka at unprecedented temporal resolution. The
upper 2850 m (back to 31.2 ka BP) have been dated using
annual-layer counting. Here we...
The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation
deep ice core that provides Antarctic climate records of
the past ~68 ka at unprecedented temporal resolution. The
upper 2850 m (back to 31.2 ka BP) have been dated using
annual-layer counting. Here we...
The global biogeochemical cycle of methane has received wide attention because of methane's role as a greenhouse gas. Measurements of methane in air trapped in Greenland ice cores provide a high-resolution record of methane levels in the atmosphere over the past ~100 ka, providing clues about what controls the methane...
We present techniques for obtaining large (∼100 L STP) samples of ancient air for analysis of ¹⁴C of methane (¹⁴CH₄) and other trace constituents. Paleoatmospheric ¹⁴CH₄ measurements should constrain the fossil fraction of past methane budgets, as well as provide a definitive test of methane clathrate involvement in large and...
Measurements of helium isotopes in particles separated from polar ice demonstrate that extraterrestrial ³He dominates the ³He flux at the GISP2 (Greenland) and Vostok (Antarctica) ice core sites. Replicate measurements of late Holocene ice samples yield ³He fluxes of 0.62±0.27×10⁻¹² cm³ STP cm⁻² ka⁻¹ (GISP2) and 0.77 ± 0.25 ×...
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of...