Sediment transport by Greenland's icebergs

Area of Science:

• Glaciology
• Geochemistry
• Paleoclimatology

Background:

• Ice-rafted debris (IRD) from Greenland's tidewater glaciers influences biogeochemical cycles and fjord sedimentation.
• Understanding IRD entrainment in basal ice is crucial for predicting export, but quantitative models are lacking.

Purpose of the Study:

• To quantify sediment transport in basal ice and estimate IRD fluxes from Greenland's tidewater glaciers.
• To develop a numerical model linking ice yield to sediment yield for predicting IRD export.

Main Methods:

• Collected 210 debris-rich iceberg samples from three fjord systems.
• Developed a numerical process model for basal ice erosion and entrainment.
• Extrapolated findings across Greenland's marine-terminating outlets.

Main Results:

• Sediment concentrations in icebergs ranged from 0.1% to 45% (3.48% median).
• Established a relationship between catchment ice yield and sediment yield.
• Estimated an annual IRD export of 454 Mt a^-1, up to one-third of Greenland's total sediment transport.

Conclusions:

• Icebergs play a significant role in Greenland's sediment budget.
• The study improves understanding of sediment export from glaciers and ice sheets in a warming climate.