Depositional settings of an arctic coast: a shallow seismic investigation

• Main Authors: Radosavljevic, Boris, Lantuit, Hugues, Fritz, Michael, Overduin, Paul, Krautblatter, Michael
• Format: Conference Object
• Language: unknown
• Published: 2013
• Subjects: Arctic; Canada; Herschel Island; Yukon; Climate change; Herschel; Ice; permafrost
• Online Access: https://epic.awi.de/id/eprint/34562/; https://epic.awi.de/id/eprint/34562/1/2013_Radosavljevic_AK_Permafrost.pdf; https://hdl.handle.net/10013/epic.42780; https://hdl.handle.net/10013/epic.42780.d001

There is almost twice as much carbon stored in permafrost soils than in the atmosphere. With the potential for positive feedback to ongoing climate change, processes leading to the release and sequestration of the carbon have received much scientific attention. These processes include coastal erosion and burial in the marine realm. Even though protected from wave attack for nine months of the year, arctic coasts made of unconsolidated sediments erode very rapidly due to the combined effects of mechanical and thermal erosion processes. In particular, coasts characterized by ice-rich permafrost, like the western Canadian Arctic are especially vulnerable to climate change. Although carbon deposition on continental shelves and fluvial input has been quantified, deposition in the nearshore zone has not been thoroughly investigated. This is due to logistical difficulties, but also because the arctic shoreface is deemed to be erosive, rather than depositional. However, sea-level rise and thermal degradation of subsea permafrost may create accommodation space where deposition can occur. Deposition may also be governed by the intensity of nearshore processes, such as ice gouging. This study investigates the nearshore stratigraphy along different parts of the island and the possibility of carbon sequestration in the marine nearshore zone in the vicinity of Herschel Island, Yukon Territory, Canada. Utilizing a shallow seismic profiling system, areas of deposition were identified in the SE region of the island. This area is protected from prevailing winds from the NE by the island itself. To a degree, the island also shields this area from ice movement on the open sea and associated ice-gouging. In comparison with transects around the island, it was found that exposition, not depth control the depositional regime. Exposure to ice processes is indicated by highly disturbed stratigraphy.