Tracing Greenland Ice Sheet dynamics during past warm climates

Understanding the response of the Greenland Ice Sheet to past climate variability is essential for improving projections of its future evolution and contributions to sea-level rise. As part of the ChronIce project (Chronicling Greenland Ice Sheet evolution through past warm climates), this study investigates the response of the northern Greenland Ice Sheet to past climate forcing by reconstructing changes in physical weathering, erosion, and ice–ocean dynamics. We focus on North-West Greenland using a unique marine sedimentary archive recovered during International Ocean Discovery Program Expedition 400.

Temporal variations in glacial outlet provenance, weathering intensity, and erosion are examined using detrital mineralogical and geochemical approaches applied to sediment records from sites U1604, U1606, U1607 and U1608. Heavy mineral fractions are analyzed using Automated Quantitative Mineralogy–Scanning Electron Microscopy (AQM-SEM) and Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA-ICP-MS) that enables single-grain U–Pb geochronology and provenance fingerprints of ice-rafted debris (IRD). Here we will show results from zircon, apatite, titanite, and other datable minerals which, in combination with IRD grain-size and textural analyses, can provide new insights on sediment transport pathways, weathering processes and source regions linked to glacial erosion during the late Pliocene and Pleistocene.