Ground‐penetrating radar (GPR) investigations of a large‐scale buried ice‐marginal landsystem, Skeiðarársandur, SE Iceland

Abstract

The sedimentary record of Icelandic ice-contact environments provides critical insights into past glacier margin dynamics and position, relative sea level, and the geomorphic processes that drive the evolution of proglacial environments. This important archive has been little exploited, however, with most glacier and sea-level reconstructions based on limited sedimentary exposures, coring and surface geomorphic evidence. We report an extensive (42 km of data within a 24-km 2 study area) and deep (reflections recorded at depths up to 100 m) lowfrequency (40 and 100 MHz) ground-penetrating radar (GPR) survey of the Sandg ıgur moraines, SE Iceland. GPR profiles reveal a much larger (67 m high) and extensive (1.25 km wide) buried moraine ridge than that suggested by surface topography (typically 125 m wide and 7 m high). These data reveal that the Sandg ıgur moraines was deposited during a major Holocene re-advance of Skeiðar arj€ okull. The moraine ridge is buried by sediments dominated by glacifluvial deposits with an estimated sediment volume of 1.04 km 3 . We combine GPR-derived subsurface architecture and the surface morphology to develop a conceptual model detailing the geomorphic evolution of the moraine and surrounding region. These results provide new insights into the Holocene evolution of Skeiðar arsandur, identifying the presence of a former major ice-margin position, as well as a past relative sea-level limit. Furthermore, we establish that sediment supply and available terrestrial accommodation space are dominant drivers in the formation and evolution of vast sandar environments.

Geophysical reconstruction of the late Holocene proximal proglacial landsystem at Skeiðarársandur, southeast Iceland

“…In western Skeiðarársandur, a large and partially buried ice‐marginal landsystem related to the Sandgígjur (alternatively known as ‘Sandgígur’ in historic maps and previous literature) moraines (Fig. 1) has been identified (Harrison et al ., 2022). This moraine and associated ice‐contact/end‐moraine fan are hypothesised to represent a pre‐LIA terminus position of Skeiðarárökull (Harrison et al ., 2022).…”

“…1) has been identified (Harrison et al ., 2022). This moraine and associated ice‐contact/end‐moraine fan are hypothesised to represent a pre‐LIA terminus position of Skeiðarárökull (Harrison et al ., 2022). Surface and subsurface components of the Sandgígjur moraine indicate a maximum height of 67 m (based upon a radiowave velocity of 0.13 m $${\text{ns}}^{-1}$$) (Harrison et al ., 2022).…”

Simulation of Freeze–Thaw and Melting of Buried Ice in Longbasaba Moraine Dam in the Central Himalayas Between 1959 and 2100 Using COMSOL Multiphysics

“…Interferometric synthetic aperture radar (InSAR) and persistent scatterer interferometry (Dini et al., 2019; Hooper et al., 2012; Li et al., 2015; Tofani et al., 2013) techniques have been used to investigate the stability of moraines and slopes around glacial lakes. Structure and seepage inside moraine dams have been studied using ground‐penetrating radar, electrical resistivity tomography, and the self‐potential method (Harrison et al., 2022; Rajaure et al., 2018; Thompson et al., 2012). Moraine dam research has transitioned from qualitative descriptions of dam morphology and internal structure to quantitative analyses that combine field observations, tests, and simulations.…”

“…Moraine dam research has transitioned from qualitative descriptions of dam morphology and internal structure to quantitative analyses that combine field observations, tests, and simulations. Most qualitative analyses have focused on dam geometry (Fujita et al, 2013;Hu et al, 2020), surface morphology (Dini et al, 2019;Hooper et al, 2012;Li et al, 2015;Tofani et al, 2013), internal structure and seepage conditions (Harrison et al, 2022;Rajaure et al, 2018;Thompson et al, 2012). And some researches also addressed on dam failure mechanisms were initially based on laboratory experiments (Balmforth et al, 2008(Balmforth et al, , 2009) and subsequently focused on numerical simulations (Begam et al, 2018;Minussi & Maciel, 2012;Osti et al, 2011).…”

Simulating the freeze-thaw and buried ice melting process of the Longbasaba moraine dam (Himalayas) based on the heat transfer module of COMSOL Multiphysics from 1959 to 2100

“…Interferometric synthetic aperture radar (INSAR) and persistent scatterer interferometry (Dini et al, 2019;Hooper et al, 2012;Li et al, 2015;Tofani et al, 2013) techniques have been used to investigate the stability of moraines and slopes around glacial lakes. Ground-penetrating radar, electrical resistivity tomography, and the self-potential method (Harrison et al, 2022;Rajaure et al, 2018;Thompson et al, 2012) have been used to detect the internal structure and seepage state inside moraine dams. Most existing studies on moraine dam stability involved a qualitative analysis of the geometrical shape, surface morphology, internal structure, and seepage conditions of a moraine dam.…”