Dynamic Holocene glacial history of St. Jonsfjorden, Svalbard

• Published in: Boreas
• Main Authors: Farnsworth, Wesley R., Ingólfsson, Ólafur, Noormets, Riko, Allaart, Lis, Alexanderson, Helena, Henriksen, Mona, Schomacker, Anders
• Format: Article in Journal/Newspaper
• Language: English
• Published: John Wiley & Sons Inc. 2017
• Subjects: Geology; Svalbard; Osbornebreen; glacier; Modiolus modiolus; Spitsbergen
• Online Access: https://lup.lub.lu.se/record/1ca2e5e6-24da-4796-905d-57964c59c431; https://doi.org/10.1111/bor.12269

Evidence of a dynamic Holocene glacial history is preserved in the terrestrial and marine archives of St. Jonsfjorden, a small fjord-system on the west coast of Spitsbergen, Svalbard. High-resolution, remotely sensed imagery from marine and terrestrial environments was used to construct geomorphological maps that highlight an intricate glacial history of the entire fjord-system. The geomorphology and stratigraphy indicate an early Holocene local glacier advance constrained to the Lateglacial–early Holocene transition. Identification and 14C dating of the thermophilous bivalve mollusc Modiolus modiolus to 10.0±0.12 cal. ka BP suggest a rapid northward migration of the species shortly after deglaciation. Further evidence enhances the understanding of the onset and subsequent climax of the Neoglacial-Little Ice Age in inner St. Jonsfjorden. The present-day terminus of Osbornebreen, the dominating glacier system in St. Jonsfjorden, is located over 8.5 km up-fjord from its Neoglacial maximum extent. Cross-cutting relationships suggest subsequent advances of all the smaller glaciers in the area following the break-up of Osbornebreen. Glacial deposits, landforms and their cross-cutting relationships observed in both terrestrial and marine settings imply a complex and highly dynamic environment through the later part of the Holocene.