Vestfirdir -- almost an island, where the growth and retreat of glaciers show some connections with the East Greenland coastal zone and some with the Iceland mainland. Here the Dranga and Glama plateaux have both supported ice caps that have come and gone, sometimes in sync with the ice masses elsewhere, and sometimes not.......
The Dranga and Glama ice caps, according to various authors. At intervals following the collapse of the LGM ice cap over Vestfirdir, these two ice caps have coalesced into a single unit.
Landscape types in Vestfirdir. At times the plateau supported a singe ice cap with two m ain cemntres of accumulation and radial ice flow.
I have already flagged up the connections between East Greenland and NW Iceland, but as research proceeds, the wider the scatter of dates there seems to be, for the key glacial events such as glacier extinctions, rejuvenations and surges. Both Drangajokull and Glamujokull seem to have melted away completely during the Holocene. Both seem to have been regenerated during the Little Ice Age, but subsequently Glamujokull has disappeared again while Drangajokull has survived. The three outlet glaciers of Drangajokull -- namely Kaldalonsjokul, Reykjafjardarjokul and Leirufjardarjokul -- have all surged intermittently within the past 300 years, but not entirely in harmony.
These are the dates of the recent (Little Ice age) surges:
Reykjarfjarðarjökull 1846, ~1886, ~1910, 1934–1939, and 2002–2006Leirufjarðarjökull ~ 1700?, 1846, 1898, 1938–1942, and 1996–2001
Kaldalónsjökull ~1740, 1780?, 1810?, 1820, 1860,1920, 1936–1940, and 1996–2001
These surges are controlled by regional climatic variations, the precise glaciological characteristics of the glacier catchment areas, and by volcanic events and ash clouds (layers of ash on glacier surfaces can have a significant effect in lowering albedo and increasing melting rates.
Ice edge positions following the LGM and preceding the Little Ice Age are difficult to establish with certainty. The assumption that the big moraines in the Reykjafordur and Kaldalon valleys are of Younger Dryas age are looking a little shaky -- and in now seems (from recent work) that they may have been formed a little later, in the Pre-Boreal period, around 10,300 - 9,000 yrs BP. They are related to the moraines of the Budi stage in South Iceland, but are not exactly synchronised.
When the outermost moraine in Reykjafjordur was formed, relative sea level seems to have been around 32m asl. The moraine has a planed top, and there are exposures of washed rock surfaces and washed till in the vicinity. Was this the equivalent of the Alftanes stage (Older Dryas) in south Iceland? Quite possibly. And does the Seleyri moraine in Kaldalon date from the same stage? That seems logical to me..........
When the outermost moraine in Reykjafjordur was formed, relative sea level seems to have been around 32m asl. The moraine has a planed top, and there are exposures of washed rock surfaces and washed till in the vicinity. Was this the equivalent of the Alftanes stage (Older Dryas) in south Iceland? Quite possibly. And does the Seleyri moraine in Kaldalon date from the same stage? That seems logical to me..........
This map of glacier stages in Reykjafjordur is based on fieldwork by the DUVP team in 1975. Reference -- John 1975. It shows three major ice front positions in the lower part of the valley. The more recent research by Brynjolfsson and others concentrates on the moraines in the upper valley which are related to the Little Ice Age.
European Glacial Landscapes
The Holocene
2024, Pages 193-224
Chapter 12 - Holocene glacial history and landforms of Iceland
Ívar Örn Benediktsson, Skafti Brynjólfsson, Lovísa Ásbjörnsdóttir, Wesley R. Farnsworth
https://www.sciencedirect.com/science/chapter/edited-volume/abs/pii/B978032399712600012X?via%3Dihub
Extract from Abstract
Climate amelioration in the Early Holocene was punctuated by the preboreal readvance of the Iceland Ice Sheet (IIS) between c. 11.3 and 10.4 cal ka BP, as manifested by raised shorelines and ice-marginal landforms below and inside Younger Dryas shorelines and moraines, respectively. By about 9 ka BP, most glaciers had become smaller than present and crustal rebound was completed. The Early Holocene retreat of the IIS is widely marked by end moraines in the highlands. Declining temperatures after the Holocene Thermal Maximum (HTM c. 8.5–6.5 cal ka BP in Iceland), during which glaciers were largely absent, resulted in the onset of the neoglaciation and the reformation of ice caps at 5.5–4.4 cal ka BP, with many outlet glaciers reaching their maximum Neoglacial extent at different times until as late as 1.1 cal ka BP. The Little Ice Age maximum glacier extent occurred either in the 1700s or the late 1800s. Since then, Icelandic glaciers have been retreating apart from observed still-stands or readvances from the 1960s–70s until the mid-1990s.
================
In 1983 Eggert Larusson, who was a team member of our Durham University Vestfirdir Project in 1973-77, tried to unravel the sequence of glacial events in his 1983 doctorate thesis. he also tried to relate these stages to marine limits and lower terraces and other shorelines. He referred to "Latragrunn stage" when Vestfirdir was completely covered by its own independent ice cap --- during the LGM. Then there was a "Tjaldanes stage" when relative sea-level was around 11-22m asl -- and this must be the equivalent of of the "Jokulgardir stage" in Kaldalon and the Kirkjubol stage in Reykjafjordur. http://etheses.dur.ac.uk/7787/
Larusson, Eggert (1983) Aspects of the glacial geomorphology of the Vestfirdir Peninsula of northwest Iceland with particular reference to the Vestur-Isafjardarsysla area.
Doctoral thesis, Durham University.
Abstract
The evolution of the landscape of Vestfir6ir, made almost entirely of volcanic rocks, is traced from the lilocene, when the oldest rocks formed, through the Pliocene and Pleistocene. Volcanic activity ceased first in the north western part leaving a basalt plateau with occasional large volcanoes protruding. Fluvial erosion, guided by a westerly dip of the plateau and tectonic lineaments, left a well developed drainage pattern there by the rime volcanic activity ceased in the southeast. The snowline fluctuated widely during the Plio-Pleistocene. Cirque and valley glaciations were very effective in sculpturing the landscape where the preglacial relief was greatest, in the northwest. Ice sheet glaciations affected the whole peninsula and offshore areas with linear erosion dominant in the northwest and areal scouring elsewhere. The glacial geomorphology of Dyrafjorour and northern Arnarfjorour is mapped. The highest marine limit is in the Nupur area, about 110 m, and shorelines and marine limits higher than 70 m are at 7 other localities at least. At least' two stages of glacial readvances are recognized: The Tjaldanes stage occurred when sea level was between 11 and 22 m and is probably of "Younger Dryas" age; later a readvance occurred in the cirques in the area. On the basis of evidence on cirque distribution, cirque elevation, zeolite zonation, distribution of glacial erosional landscapes, glacial history, marine limits, ice cap profiles and shelf moraine a model of maximum glaciations of Vestfir6ir is proposed: The whole of Vestfirdir and the surrounding shelf areas was completely ice covered with no ice free areas. Such a stage of glaciation, the Latragrunn stage, probably prevailed in the Vestfirdir area during the last glaciation.
=====================
See also:
https://www.researchgate.net/publication/377874262_Moraine_stages_in_the_Reykjarfjordur_outlet_glacier_trough
Extract from Abstract
Climate amelioration in the Early Holocene was punctuated by the preboreal readvance of the Iceland Ice Sheet (IIS) between c. 11.3 and 10.4 cal ka BP, as manifested by raised shorelines and ice-marginal landforms below and inside Younger Dryas shorelines and moraines, respectively. By about 9 ka BP, most glaciers had become smaller than present and crustal rebound was completed. The Early Holocene retreat of the IIS is widely marked by end moraines in the highlands. Declining temperatures after the Holocene Thermal Maximum (HTM c. 8.5–6.5 cal ka BP in Iceland), during which glaciers were largely absent, resulted in the onset of the neoglaciation and the reformation of ice caps at 5.5–4.4 cal ka BP, with many outlet glaciers reaching their maximum Neoglacial extent at different times until as late as 1.1 cal ka BP. The Little Ice Age maximum glacier extent occurred either in the 1700s or the late 1800s. Since then, Icelandic glaciers have been retreating apart from observed still-stands or readvances from the 1960s–70s until the mid-1990s.
================
In 1983 Eggert Larusson, who was a team member of our Durham University Vestfirdir Project in 1973-77, tried to unravel the sequence of glacial events in his 1983 doctorate thesis. he also tried to relate these stages to marine limits and lower terraces and other shorelines. He referred to "Latragrunn stage" when Vestfirdir was completely covered by its own independent ice cap --- during the LGM. Then there was a "Tjaldanes stage" when relative sea-level was around 11-22m asl -- and this must be the equivalent of of the "Jokulgardir stage" in Kaldalon and the Kirkjubol stage in Reykjafjordur. http://etheses.dur.ac.uk/7787/
Larusson, Eggert (1983) Aspects of the glacial geomorphology of the Vestfirdir Peninsula of northwest Iceland with particular reference to the Vestur-Isafjardarsysla area.
Doctoral thesis, Durham University.
Abstract
The evolution of the landscape of Vestfir6ir, made almost entirely of volcanic rocks, is traced from the lilocene, when the oldest rocks formed, through the Pliocene and Pleistocene. Volcanic activity ceased first in the north western part leaving a basalt plateau with occasional large volcanoes protruding. Fluvial erosion, guided by a westerly dip of the plateau and tectonic lineaments, left a well developed drainage pattern there by the rime volcanic activity ceased in the southeast. The snowline fluctuated widely during the Plio-Pleistocene. Cirque and valley glaciations were very effective in sculpturing the landscape where the preglacial relief was greatest, in the northwest. Ice sheet glaciations affected the whole peninsula and offshore areas with linear erosion dominant in the northwest and areal scouring elsewhere. The glacial geomorphology of Dyrafjorour and northern Arnarfjorour is mapped. The highest marine limit is in the Nupur area, about 110 m, and shorelines and marine limits higher than 70 m are at 7 other localities at least. At least' two stages of glacial readvances are recognized: The Tjaldanes stage occurred when sea level was between 11 and 22 m and is probably of "Younger Dryas" age; later a readvance occurred in the cirques in the area. On the basis of evidence on cirque distribution, cirque elevation, zeolite zonation, distribution of glacial erosional landscapes, glacial history, marine limits, ice cap profiles and shelf moraine a model of maximum glaciations of Vestfir6ir is proposed: The whole of Vestfirdir and the surrounding shelf areas was completely ice covered with no ice free areas. Such a stage of glaciation, the Latragrunn stage, probably prevailed in the Vestfirdir area during the last glaciation.
=====================
See also:
https://www.researchgate.net/publication/377874262_Moraine_stages_in_the_Reykjarfjordur_outlet_glacier_trough
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