Dating and analysis of the Hinlopen Megaslide, northern Svalbard

Abstract

During a research cruise in the summer of 2022, a number of sediment cores were collected from the main headwall scar area of the Hinlopen Megaslide, northern Svalbard. In this study two of those sediment cores have undergone 14C AMS radiocarbon dating and a multi-proxy analysis to determine an accurate age for the slide deposits in this location. The results have been calibrated using the Marine20 Radiocarbon Calibration Curve (Heaton et al., 2020) and a ΔR value of 70±30 (Mangerud and Svendsen., 2017). Two different landslide events have been identified, one is from the southern scar lobe dating to >40ka yrs BP and the other was taken from the eastern headwall area and dates between 15-13ka yrs BP. These results, along with the ages from Winkelmann et al., (2007) mean that there has been at least a minimum of three landslide events in the Hinlopen Megaslide Complex. The understanding so far is that the 30ka yrs BP age from Winkelmann et al., was the initial main slide event which has been challenged by the results of this study. All three events occur during warmer climatic conditions, being the Kapp Ekholm Interstadial and the Bølling-Allerød Interstadial, and this implies that warmer climates have a large impact on the stability of the material at the continental shelf at this location. The potential of a failure in the future has been proposed (Geissler et al., 2016) due to the presence of internally deformed sediment just north of the slide scar. Here surface cracks and slump deposits are frequent and the implication that all three known slide events occurred during warmer periods means that the occurrence of a future event is not impossible.