Denali Ice Core trace element laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) data in basal ice, Begguya Plateau, Denali National Park, Alaska, 2025

A robust chronology has been developed for the Denali Ice Cores, Begguya, Alaska (62.93 N 151.083 W, 3912 m asl (meters above sea level); also known as Mount Hunter) using a combination of techniques including annual‑layer counting, volcanics, radiocarbon dating, and the 1963 atmospheric nuclear‑weapons‑testing horizon. Radiocarbon dating confirms that there is early Holocene ice preserved at the bottom of the Denali Ice Cores. To confirm this, researchers at the University of Maine have produced oxygen‑isotope records. Examining the data from the twin cores, we see replicate isotope profiles in the bottom 8 meters of ice, showing a sharp decrease of δ^18O (oxygen‑18 isotope ratio) of nearly 6 ‰ (permil) near the bottom. To investigate whether this decrease is a climate signal or an artifact of basal‑ice dynamics, we collected trace‑element data across the oxygen‑isotope decrease. Because the basal ice of the Denali Ice Cores contains too high a sediment load to be melted and analyzed with aqueous inductively coupled plasma mass spectrometry (ICP‑MS), we analyzed Na (sodium), Mg (magnesium), Cu (copper), Pb (lead), Al (aluminum), Ca (calcium), Fe (iron), and S (sulfur) in the basal ice (207.35 m to 208.76 m depth) using laser‑ablation inductively coupled plasma mass spectrometry (LA‑ICP‑MS). The data are still being analyzed and compared with data from other methods to determine the cause of the oxygen‑isotope‑signal decrease. Researchers seeking to use this dataset should proceed with caution, as there is some evidence of contamination in the Pb and Cu analyses.