High Relative Sea Level during the Bolling Interstadial in Western Iceland: A Reflection of Ice-Sheet Collapse and Extremely Rapid Glacial Unloading

Inǵólfsson, Ólafur; Norðdahl, Hreggviður

doi:10.2307/1552224

Cited by 34 publications

(58 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…BIESSY ET AL. : POST-GLACIAL REBOUND IN ICELAND 1982; Norddahl and Halfidason, 1992;Ingolfsson and Norddahl, 2001]. Recent inland geological observations supported by dating in the south and in the northwest shelves imply a more limited extent at the LGM and at the Younger Dryas [Geirsdottir et al, 1997;Andrews et al, 2000;Andrews and Helgadottir, 2003].…”

Section: Tc3002supporting

confidence: 75%

Fast and partitioned postglacial rebound of southwestern Iceland

et al. 2008

View full text Add to dashboard Cite

International audienceLocated both on the Mid-Atlantic Ridge and above a mantle plume, Iceland is subject to horizontal and vertical motions. Many studies described these deformations in terms of rifting episodes that have combined both extensional tectonics and magmatism. However, few studies have described the glacio-isostatic response induced by the retreat of the Weichselian ice cap. The melting of this ice cap induced a postglacial rebound for the whole of Iceland that may be controlled by the geodynamic setting and the rheological layering of the lithosphere. This study is devoted to (1) understanding the Holocene rebound on the southwestern coast and (2) estimating the asthenosphere viscosity and depth beneath Iceland. Two stages of holocene evolution were determined by means of GPS profiles, morphological observations, and data compilation. The first stage corresponds to a vertical uplift of 67.5 to 157.5 m. It started at 10,000 years BP and ended at 8500 years BP implying uplift rates between 4.5 and 10.5 cm/a. It was a quick isostatic response to the fast ice retreat. The second stage had vertical motion of tens of meters with a probable tectonic origin and started at 8500 years BP. The uplift rate is 1 to 2 orders of magnitude slower than the one during the first stage. Uplift partitioning during the first stage was controlled by the thermal state of the lithosphere, the highest geothermal flux inducing the maximum uplift rates. The relaxation time for uplift provides a viscosity estimate of 5.45.8 — 1019 Pa s for the asthenosphere. This value is similar to those determined for glacial areas in different continental contexts. However, the flexural wavelength indicates a shallower asthenosphere than that occurring in continental domains. Therefore this study highlights a coupling between the thermal structure of the Icelandic asthenosphere and the glacial rebound

show abstract

Section: Tc3002supporting

confidence: 75%

Fast and partitioned postglacial rebound of southwestern Iceland

et al. 2008

View full text Add to dashboard Cite

show abstract

“…2000; 2002; Eiríksson et al . ; Ingólfsson & Norðdahl ; Evans & Twigg ; Geirsdóttir et al . , ; Norðdahl & Pétursson ; Principato et al .…”

mentioning

confidence: 99%

GIS analysis of cirques on Vestfirðir, northwest Iceland: implications for palaeoclimate

Principato

Lee

2014

Boreas

View full text Add to dashboard Cite

This study presents the first regional analysis of cirques on Vestfirðir, NW Iceland, using a Geographical Information System (GIS). The length, width, elevation of cirque-floor, latitude and the distance to the modern coastline (both ocean and fjord coastlines) of cirques were quantified using ArcGIS. The topographical analysis revealed a total of 100 cirques on western and northern Vestfirðir. Several additional cirques are present, but they had poorly defined toewalls, making the cirque-floor difficult to identify. Mean cirque length is 515 m and mean cirque width is 752 m. The modal orientation of the aspect of cirques is northeast, with a strong secondary mode to the northwest. Cirques at low elevations are more abundant close to the ocean, whereas cirques further from the ocean are present at high elevations. Three techniques were used to reconstruct past equilibrium-line altitudes (ELAs) of cirque glaciers: the cirque-floor method, the altitude-ratio method and the accumulation-area ratio method. The largest range of past ELAs is generated from the cirque-floor method with values from 40 up to 730 m. Mean past ELA values range from ∼395 to 423 m depending on the method used to reconstruct former ELAs. A strong positive relationship is observed between past ELA values and distance to the ocean demonstrating the importance of access to a moisture source for glacier survival. This relationship is stronger than the relationship between former ELAs and latitude. Based on the small size of cirque glaciers, it is likely that even minor fluctuations in the Irminger Current and the East Greenland Current influence cirque glaciation on Vestfirðir.

show abstract

“…Raised marine shorelines, radiocarbon dated to 14.7 cal. ka BP, show that the relative sea level in the region was up to ~150 m higher than present (Ingólfsson & Norðdahl ; Norðdahl & Ingólfsson ). The subsequent marked decrease in the volume of ice covering Iceland during the remainder of the Bølling and into the Allerød (13.9–12.8 cal.…”

Section: The Study Area and Its Geological Contextmentioning

confidence: 95%

“…; Norðdahl & Ingólfsson ). The collapse of this marine‐terminating ice mass was most probably driven by a global rise in sea level resulting from the decay of other major Northern Hemisphere ice sheets (Ingólfsson & Norðdahl ; Norðdahl & Ingólfsson ; Patton et al . ).…”

Section: The Study Area and Its Geological Contextmentioning

confidence: 99%

“…Glaciotectonism observed in the coastal exposures in Melasveit has previously been attributed to an ice advance occurring shortly after 14.0 cal. ka BP, possibly as a result of the dynamic response of the western Iceland ice sheet following the earlier collapse of its marine‐based component (Ingólfsson & Norðdahl ; Norðdahl et al . ; Ingólfsson et al .…”

Section: The Study Area and Its Geological Contextmentioning

confidence: 99%

See 1 more Smart Citation

Active retreat of a Late Weichselian marine‐terminating glacier: an example from Melasveit, western Iceland

Sigfúsdóttir

Benediktsson

Phillips

2018

Boreas

View full text Add to dashboard Cite

Large and complete glaciotectonic sequences formed by marine‐terminating glaciers are rarely observed on land, hampering our understanding of the behaviour of such glaciers and the processes operating at their margins. During the Late Weichselian in western Iceland, an actively retreating marine‐terminating glacier resulted in the large‐scale deformation of a sequence of glaciomarine sediments. Due to isostatic rebound since the deglaciation, these formations are now exposed in the coastal cliffs of Belgsholt and Melabakkar‐Ásbakkar in the Melasveit district, and provide a detailed record of past glacier dynamics and the inter‐relationships between glaciotectonic and sedimentary processes at the margin of this marine‐terminating glacier. A comprehensive study of the sedimentology and glaciotectonic architecture of the coastal cliffs reveals a series of subaquatic moraines formed by a glacier advancing from Borgarfjörður to the north of the study area. Analyses of the style of deformation within each of the moraines demonstrate that they were primarily built up by ice‐marginal/proglacial thrusting and folding of marine sediments, as well as deposition and subsequent deformation of ice‐marginal subaquatic fans. The largest of the moraines exposed in the Melabakkar‐Ásbakkar section is over 1.5 km wide and 30 m high and indicates the maximum extent of the Borgarfjörður glacier. Generally, the other moraines in the series become progressively younger towards the north, each designating an advance or stillstand position as the glacier oscillated during its overall northward retreat. During this active retreat, glaciomarine sediments rapidly accumulated in front of the glacier providing material for new moraines. As the glacier finally receded from the area, the depressions between the moraines were infilled by continued glaciomarine sedimentation. This study highlights the dynamics of marine‐terminating glaciers and may have implications for the interpretation of their sedimentological and geomorphological records.

show abstract

High Relative Sea Level during the Bolling Interstadial in Western Iceland: A Reflection of Ice-Sheet Collapse and Extremely Rapid Glacial Unloading

Cited by 34 publications

References 0 publications

Fast and partitioned postglacial rebound of southwestern Iceland

Fast and partitioned postglacial rebound of southwestern Iceland

GIS analysis of cirques on Vestfirðir, northwest Iceland: implications for palaeoclimate

Active retreat of a Late Weichselian marine‐terminating glacier: an example from Melasveit, western Iceland

Contact Info

Product

Resources

About