Evaluation of Mumiyo Deposits From East Antarctica as Archives for the Late Quaternary Environmental and Climatic History

Abstract

AbstractMumiyo deposits form in the vicinity of snow petrel (Pagodroma nivea) nesting sites and consist of fossil stomach oil (mumiyo), guano, and minerogenic material. Here we evaluate mumiyo deposits from the inland mountain ranges of central Dronning Maud Land as high‐resolution archives for paleoenvironmental reconstructions in Antarctica. Investigation of internal structures and chemical composition shows that the lamination reflects progressive sedimentation, despite the irregular outer morphology of the deposits. Detailed radiocarbon analysis demonstrates that stratigraphies are intact: 14C ages become successively younger upwards in the deposits. Fatty acid and n‐alcohol composition was determined on samples from eight mumiyo deposits. Dominance of low molecular weight compounds (C14 to C18) points to a dietary signal; however, the relatively low proportions of unsaturated compounds compared to fresh stomach oils indicates some postdepositional degradation. We found marine diatoms in the mumiyo, which potentially provide a proxy for sea ice conditions in the foraging habitat of the petrels. Age ranges of the investigated deposits suggest occupation of the analyzed sites by snow petrels from 17 ka to >58 ka. Changes in deposition rates point to higher occupation frequency in Petermann Range from 46 to 42 ka compared to the late marine isotope stage 3 and the Last Glacial Maximum.