Holocene glacial history of Svalbard: Status, perspectives and challenges

The submarine landforms and shallow sediment record are presented from Hambergbukta, southeastern Spitsbergen using swath‐bathymetric, subbottom acoustic, and sediment core data. The mapped landforms include large terminal and end‐moraines with associated debrisflow aprons on their distal flanks, drumlinized till surface, glacial lineations, medial and retreat moraines, crevasse squeeze ridge networks, eskers, as well as iceberg‐produced terraces and plough‐marks. Analysis of the landforms and landform assemblages in combination with the sediment core data and aerial imagery studies reveal a complex and dynamic glacial history of Hambergbukta. We present a detailed history of Hambergbreen glacier indicating two previously unknown surges as well as new details on the nature of the subsequent ice‐margin retreat. The results from two gravity cores combined with the shallow acoustic stratigraphy and high‐resolution bathymetry suggest that the c. AD 1900 surge was less extensive than previously thought and the retreat was most likely rapid after the c. AD 1900 and 1957 surges of the Hambergbreen. Mixed benthic foraminifera collected from the outer fjord basin date to 2456 cal. a BP, suggesting older sediments were re‐worked by the c. AD 1900 surge. This highlights the importance of exercising caution when using foraminifers for dating surge events in fjord basins enclosed by prominent end‐moraines.

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“…2010; Farnsworth et al . 2020). The continuous Late‐ and Postglacial sedimentary record is often disturbed by glacier surges (Benn et al .…”

Section: Figmentioning

confidence: 99%

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

Noormets¹,

Flink

Kirchner

2020

Boreas

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“…Following from Darcy's law and the conservation of mass, the three-dimensional groundwater flow equation fundamental for groundwater modelling can be described as follows (Fitts, 2002):…”

Section: Groundwater Flowmentioning

confidence: 99%

“…The range of the hydraulic conductivity values of the Carolinefjellet and Helvetiafjellet formations (Festningen Sandstone not included) was defined by the 25 %, 50 % and 75 % percentiles of a loglogistic probability fit of the measured values (details provided in the Supplement). Ranges of hydraulic conductivity for the fluvio-deltaic succession were based on literature values from Fitts (2002). For the remaining bedrock units, we also regarded the influence of fractures (Singhal and Gupta, 2010).…”

Section: Geothermal and Hydrogeological Propertiesmentioning

confidence: 99%

“…For S s , we used a matrix compressibility of 7 × 10 −10 to 7 × 10 −8 Pa −1 (based on common estimates for fractured rocks; e.g. Domenico and Mifflin, 1965;Domenico and Schwartz, 1998;Fitts, 2002) yielding a S s of 7×10 −6 to 7×10 −4 m −1 (in line with literature values; cf. Singhal and Gupta, 2010).…”

Section: Groundwater Modelmentioning

confidence: 99%

“…Density and thermal properties compiled from aWilliams and Smith (1989),b Robertson (1988), and cManger (1963). Porosities from dFitts (2002) ande and based on works by fBurland (1990),Grundvåg et al (2019),Marshall et al (2015), Okiongbo (2011), andYang and Aplin (2004) (see text for more detail).…”

mentioning

confidence: 99%

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Numerical modelling of permafrost spring discharge and open-system pingo formation induced by basal permafrost aggradation

et al. 2020

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Abstract. In the high Arctic valley of Adventdalen, Svalbard, sub-permafrost groundwater feeds several pingo springs distributed along the valley axis. The driving mechanism for groundwater discharge and associated pingo formation is enigmatic because wet-based glaciers are not present in the adjacent highlands and the presence of continuous permafrost seems to preclude recharge of the sub-permafrost groundwater system by either a subglacial source or a precipitation surplus. Since the pingo springs enable methane that has accumulated underneath the permafrost to escape directly to the atmosphere, our limited understanding of the groundwater system brings significant uncertainty to predictions of how methane emissions will respond to changing climate. We address this problem with a new conceptual model for open-system pingo formation wherein pingo growth is sustained by sub-permafrost pressure effects, as related to the expansion of water upon freezing, during millennial-scale basal permafrost aggradation. We test the viability of this mechanism for generating groundwater flow with decoupled heat (one-dimensional transient) and groundwater (three-dimensional steady state) transport modelling experiments. Our results suggest that the conceptual model represents a feasible mechanism for the formation of open-system pingos in lower Adventdalen and elsewhere. We also explore the potential for additional pressurisation and find that methane production and methane clathrate formation and dissolution deserve particular attention on account of their likely effects upon the hydraulic pressure. Our model simulations also suggest that the generally low-permeability hydrogeological units cause groundwater residence times to exceed the duration of the Holocene. The likelihood of such pre-Holocene groundwater ages is supported by the geochemistry of the pingo springs which demonstrates an unexpected seaward freshening of groundwater potentially caused by a palaeo-subglacial meltwater “wedge” from the Weichselian. Whereas permafrost thickness (and age) progressively increases inland, accordingly, the sub-permafrost meltwater wedge thins, and less unfrozen freshwater is available for mixing. Our observations imply that millennial-scale permafrost aggradation deserves more attention as a possible driver of sustained flow of sub-permafrost groundwater and methane to the surface because, although the hydrological system in Adventdalen at first appears unusual, it is likely that similar systems have developed in other uplifted valleys throughout the Arctic.

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From everywhere all at once: Several colonization routes available to Svalbard in the early Holocene

Brožová

Bolstad²,

Seregin

et al. 2023

Ecology and Evolution

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Holocene glacial history of Svalbard: Status, perspectives and challenges

Cited by 56 publications

References 199 publications

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

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

Numerical modelling of permafrost spring discharge and open-system pingo formation induced by basal permafrost aggradation

From everywhere all at once: Several colonization routes available to Svalbard in the early Holocene

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