A dated volcano‐tectonic deformation event in Jan Mayen causing landlocking of Arctic charr

Abstract

We provide the first documentation of tectonic deformation resulting from a volcanic eruption on the island of Jan Mayen. Vertical displacement of about 14 m southwest of the stratovolcano Beerenberg is associated with an eruption in AD 1732 on its southeastern flank. The age of the uplift event is bracketed by radiocarbon-dated driftwood buried by material deposited due to uplift, and by tephra from this eruption. Constraints, inferred from radiocarbon ages alone, allow for the possibility that uplift was completed prior to the AD 1732 eruption. However, the occurrence of tephra in the sediment column indicates that some displacement was ongoing during the eruption but ceased before the eruption terminated. We attribute the tectonic deformation to intrusion of shallow magma associated with the volcanic eruption. Our results complement previous studies of volcanic activity on Jan Mayan by providing precise age constraints for past volcanic activity. Also, it raises new hypotheses regarding the nature, timing and prevalence of precursor tectonic events to Jan Mayan eruptions. The uplift caused the complete isolation of a coastal lake by closing its outlet to the sea, thus landlocking the facultative migratory fish species Arctic charr (Salvelinus alpinus).

Long-term hazard assessment of explosive eruptions at Jan Mayen (Norway) and implications for air traffic in the North Atlantic

“…1). According to Kandilarov et al (2012) and Larsen et al (2021), the Jan Mayen microcontinent (JMMC, Fig. 2a) is a structural entity enclosing the Jan Mayen Ridge (JMR) and the surrounding area, including the Jan Mayen Basin (JMB), the Jan Mayen Basin South (JMBS), the Jan Mayen Trough (JMT), and the Southern Ridge Complex (SRC) (see Fig.…”

Cosmogenic Exposure Dating (36Cl) of Landforms on Jan Mayen, North Atlantic, and the Effects of Bedrock Formation Age Assumptions on 36Cl Ages

“…Isostatic changes will also have some influence on the calculated exposure ages as they may change the elevation of a sample. A recent study by Larsen et al (2021) [2] identified a 14 m vertical tectonic displacement of southwest Beerenberg, following an eruption in 1732. So far, this is the only documented postglacial displacement, but we cannot exclude that there have been other instances of vertical displacements on the island due to both glacioisostasy and volcanic activity.…”

“…Its isolated position 550 km north of Iceland and 450 km east of Greenland in the Norwegian-Greenland Sea (Figure 1) makes it an interesting location for investigations of the climate history in the North Atlantic. A research campaign to reconstruct the glaciation and climate history of the island was therefore started in 2014 [1,2]. As part of that campaign, 89 samples for cosmogenic nuclide exposure age dating ( 36 Cl) were collected with the aim of dating glacial and volcanic events on the island.…”

“…Standard methods for age calculations assume that this equilibrium condition has been reached for all samples [5,6]. However, the assumption that the background production has had time to reach equilibrium is unlikely to be true in areas with young volcanic rocks [7][8][9], such as Jan Mayen [1,2,10]. If equilibrium conditions are assumed incorrectly, the background production subtraction will be too large, resulting in an exposure age that is too young.…”