Extended Data Table 2 GISP2 bedrock 10Be data
From: Greenland was nearly ice-free for extended periods during the Pleistocene
- Sample and measurement details for the 10Be samples, given with 1σ analytical uncertainty. Underlined values are the measurements used for further discussion. ‘BLK’ denotes process blanks, that is, 9Be carrier that underwent a chemical procedure identical to that of the respective samples. We processed 3–5 such process blanks for each sample to ensure robust monitoring of any contamination; the background correction was done by subtracting the mean of the 10Be atoms for all BLKs from the total 10Be atoms in the corresponding sample. ‘CB’ denotes carrier blanks, that is, 9Be carrier that did not undergo the sample and process blank chemistry, but was precipitated, dried, loaded in cathodes and sent directly to the Center for Accelerator Mass Spectrometry at the Lawrence Livermore National Laboratory for 9Be/10Be analysis. The difference between ‘CB’ and ‘BLK’ 10Be atoms allows us to estimate the 10Be contamination during the sample processing in the laboratory, which is small for the samples discussed here. During the 23 years of storage at the National Ice Core Laboratory in Boulder (1,600 m), the potential production of 10Be and 26Al in the core is of the order of several hundred atoms and is thus negligible compared to the measured values.
