Greenland tidewater glacier advanced rapidly during era of Norse settlement

Pearce, Danni M, Lea, James M, Mair, Douglas WF, Rea, Brice R, Schofield, J Edward, Kamenos, Nicholas A, Schoenrock, Kathryn M, Stachnik, Lukasz, Lewis, Bonnie, Barr, Iestyn ORCID: https://orcid.org/0000-0002-9066-8738 and Mottram, Ruth (2022) Greenland tidewater glacier advanced rapidly during era of Norse settlement. Geology, 50 (6). pp. 704-709. ISSN 0091-7613

Preview

Accepted Version Available under License In Copyright. Download (1MB) | Preview

Abstract

Our ability to improve prognostic modeling of the Greenland Ice Sheet relies on understanding the long-term relationships between climate and mass flux (via iceberg calving) from marine-terminating tidewater glaciers (TWGs). Observations of recent TWG behavior are widely available, but long-term records of TWG advance are currently lacking. We present glacial geomorphological, sedimentological, archaeological, and modeling data to reconstruct the ~20 km advance of Kangiata Nunaata Sermia (KNS; the largest tidewater glacier in southwest Greenland) during the first half of the past millennium. The data show that KNS advanced ~15 km during the 12th and 13th centuries CE at a rate of ~115 m a–1, contemporaneous with regional climate cooling toward the Little Ice Age and comparable to rates of TWG retreat witnessed over the past ~200 years. Presence of Norse farmsteads proximal to KNS demonstrates their resilience to climate change, manifest as a rapidly advancing TWG in a cooling climate. The results place limits on the magnitude of ice-margin advance and demonstrate TWG sensitivity to climate cooling as well as warming. These data combined with our grounding-line stability analysis provide a long-term record that validates approaches to numerical modeling aiming to link calving to climate.