Postglacial relative sea level change and glacier activity in the early and late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard

Abstract

Sediment cores from Kløverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kløverbladvatna became isolated from Wahlenbergfjorden c. 5.4 cal. kyr BP due to glacioisostatic rebound. During the Late Holocene, laminated clayey gyttja from lacustrine organic production and surface runoff from the catchment accumulated in the lake. The lacustrine sedimentary record suggests that meltwater only spilled over the threshold at the peak of the surge of Etonbreen in AD 1938. Hence, we suggest that this was the largest extent of Etonbreen in the (mid-late) Holocene. In Palanderbukta, a tributary fjord to Wahlenbergfjorden, raised beaches were surveyed and organic material collected to determine the age of the beaches and reconstruct postglacial relative sea level change. The age of the postglacial raised beaches ranges from 10.7 cal. kyr BP at 50 m a.s.l. to 3.13 cal. kyr BP at 2 m a.s.l. The reconstructed postglacial relative sea level curve adds valuable spatial and chronological data to the relative sea level record of Nordaustlandet.

Glacial dynamics and deglaciation history of Hambergbukta reconstructed from submarine landforms and sediment cores, SE Spitsbergen, Svalbard

“…This would have been facilitated by the higher relative sea level then (Ingólfsson & Landvik 2013; Schomacker et al . 2019; Farnsworth et al . 2020).…”

Glacier decay boosts the formation of new Arctic coastal environments—Perspectives from Svalbard

“…Another unknown is the glacioisostatic response to the massive post‐LIA ice mass loss leading to the uplift of the coastal zone. It is widely established that uplifted beaches and marine terraces, so characteristic of Svalbard coastal landscapes record uplift from glacial isostatic adjustment caused by the decay of Svalbard‐Barents Sea Ice Sheet that covered the archipelago during the Last Glacial Maximum (e.g., Forman et al, 2004; Long et al, 2012; Schomacker et al, 2019; Sessford et al, 2015). However, taking into account that the glacier advance during the Neoglacial cooling and the LIA most probably accumulated the largest ice mass during the Holocene in Svalbard (e.g., Farnsworth et al, 2018; Martín‐Moreno et al, 2017; Philipps et al, 2017) the rapid retreat of glaciers observed over the last century may have already overtaken the post‐LGM control of solid Earth motion.…”

Seasonal precipitation variability on Svalbard inferred from Holocene sedimentary leaf wax δ2H

“…Detailed methodology and full core descriptions and lithostratigraphy are presented by Schomacker et al . (2019) (Kløverbladvatna), Kjellman et al . (2020) (Austre Nevlingen), Voldstad et al .…”