Modern glacimarine processes and potential future behaviour of Kronebreen and Kongsvegen polythermal tidewater glaciers, Kongsfjorden, Svalbard

Abstract

Abstract Glacimarine dynamics and associated sedimentary processes are closely tied to glacial regime and reflect dominant climatic conditions. Quantitative measurements for subpolar glaciers, such as sediment yield, are limited especially near glacial termini where most sediment accumulates. Here we characterize the modern glacimarine environment, quantify sediment flux and yield, document landform genesis and hypothesize potential future behaviour of Kronebreen and Kongsvegen glaciers in inner Kongsfjorden, Svalbard. A minimum of 6.74×10 3 g m −2 d −1 (at least 300 mm a −1 ) of glacimarine sediment is building a grounding-line fan via submarine stream discharge from Kronebreen. Average daily sediment flux to the ice-contact basin is recorded to be 2.6×10 3 g m −2 d −1 or an average annual flux of 1.56×10 5 g m −2 a −1 . We measure an average annual ice-contact sediment yield of 1.20×10 4 tonnes km −2 a −1 associated with the rapid genesis of grounding-line landforms. With forecasted warming we expect meltwater volumes and sediment flux to increase. Grounding-line deposits may aggrade above water, tending to stabilize the terminus at least initially if the sediment is sufficient to counteract total terminus ablation. This would hold until either the glaciers next surge or climatic warming ablates the glaciers through surface melting.