Greenland Ice Sheet behavior over past warm climate periods: A provenance study

Understanding how the Greenland Ice Sheet (GrIS) has responded to past climate variability is critical for improving predictions of its future behavior and contributions to sea-level rise. As a part of the ChronIce project (Chronicling Greenland Ice Sheet evolution through past warm climates) this study aims to investigate the response of the northern GrIS to past climate forcing by documenting its history of physical weathering and ice–ocean dynamics. Temporal changes in glacial outlets sources (provenances), weathering and erosion in northwest Greenland will be investigated using a unique paleoclimatic archive recovered during Expedition 400 of the International Ocean Drilling Programme (Knutz et al. 2025). By using the X400 record we will advance the understanding of Arctic ice–ocean–climate feedback mechanisms and improve the accuracy of future projections of glacial mass loss and sea-level rise. Our analytical approach includes examining detrital heavy mineral composition using AQM-SEM (Automated Quantitative Mineralogy – Scanning Electron Microscopy; Keulen et al. 2020) and LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry). The latter also provides single-grain geochronometry as U-Pb dating, enabling precise fingerprinting of ice-rafted debris (IRD) to infer source areas of glacial erosion. Zircon, rutile, apatite, monazite and titanite were detected in the samples and will provide new insights for this provenance study. IRD analyses including grain size and grain texture will be used to reconstruct marine ice margin variability and assess the ice sheet’s response to interglacial climate warming under varying pCO₂ forcing scenarios during the Pliocene and Pleistocene. Combined with other detrital and biological proxies, mineral geochronometry on zircon, rutile, apatite, and other datable minerals provides a tool for tracing long-term evolutionary trends in GrIS weathering and ice sheet configuration. Here, we present our initial results.