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Derek Fabel - One of the best experts on this subject based on the ideXlab platform.
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A chronology for North Sea Lobe advance and recession on the Lincolnshire and Norfolk coasts during MIS 2 and 6
Proceedings of the Geologists' Association, 2019Co-Authors: David J.a. Evans, David H. Roberts, Mark D. Bateman, Jeremy C. Ely, Alicia Medialdea, Matthew J. Burke, Richard C. Chiverrell, Chris D. Clark, Derek FabelAbstract:During the last (MIS 2) and older Glaciations of the North Sea, a North Sea Lobe (NSL) of the British-Irish Ice Sheet flowed onshore and terminated on the lowlands of eastern England, constructing inset sequences of either substantial ice-marginal deposits and tills or only a thin till veneer, indicative of complex and highly dynamic glaciological behaviour. The Glaciation Limit represented by the Marsh Tills and the Stickney and Horkstow Moraines in Lincolnshire is regarded as the maximum margin of the NSL during MIS 2 and was attained at ∼19.5 ka as determined by OSL dating of overridden lake sediments at Welton le Wold. A later ice marginal position is recorded by the Hogsthorpe-Killingholme Moraine belt, within which ice-walled lake plains indicate large scale ice stagnation rapidly followed ice advance at ∼18.4 ka based on dates from supraglacial lake deposits. The NSL advanced onshore in North Norfolk slightly earlier constructing a moraine ridge at Garrett Hill at ∼21.5ka. In addition to the large ice-dammed lakes in the Humber and Wash lowlands, we propose that an extensive Glacial Lake Lymn was dammed in the southern Lincolnshire Wolds by the NSL ice margin at the Stickney Moraine. Previous proposals that older glacier Limits might be recorded in the region, lying between MIS 2 and MIS 12 deposits, are verified by our OSL dates on the Stiffkey moraine, which lies immediately outside the Garrett Hill moraine and appears to be of MIS 6 age.
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Early to middle Holocene valley Glaciations on northernmost Greenland
Quaternary Science Reviews, 2010Co-Authors: Per Möller, Anders Schomacker, Nicolaj K. Larsen, Kurt H. Kjær, Svend Funder, Henriette Linge, Derek FabelAbstract:Abstract This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18–22 cal ka BP) into the Holocene. It records the history of a shelf-based Glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine Limit formed at ∼45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from on-lapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14 C dating results, the youngest ice advance phase can be narrowed down to 14 C ages between ∼5.5–5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of ∼2500 years during which the north coast of Greenland – as opposed to today – experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which, coupled to documented HTM cold reversals, caused a lowered Glaciation Limit, and led to a positive mass balance and subsequent ice advance.
Nicolaj K. Larsen - One of the best experts on this subject based on the ideXlab platform.
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The Drangajökull ice cap, northwest Iceland, persisted into the early-mid Holocene
Quaternary Science Reviews, 2016Co-Authors: Anders Schomacker, Skafti Brynjólfsson, Julie M. Andreassen, Esther Ruth Gudmundsdóttir, Jesper V. Olsen, Bent Vad Odgaard, Lena Håkansson, Ólafur Ingólfsson, Nicolaj K. LarsenAbstract:Abstract Most glaciers and ice caps in Iceland experienced rapid deGlaciation in the early Holocene, reaching a minimum extent during the Holocene Thermal Maximum. Here we present evidence of the Holocene glacial history from lake sediment cores retrieved from seven threshold lakes around the Drangajokull ice cap in the Vestfirðir peninsula, NW Iceland. The sediment cores show on/off signals of glacial meltwater activity, as minerogenic material deposited from glacial meltwater alternates with organic-rich material (gyttja) deposited without glacial meltwater. We base the chronology of the sediment cores on 14C ages and geochemical identification of key tephra layers with known ages. A 25-cm thick layer of the Saksunarvatn tephra in Lake Skorarvatn indicates that the northern part of the ice cap had reached a similar size as today or was smaller already by 10.2 cal kyr BP. However, 14C ages of lake sediment cores from the highlands southeast of Drangajokull suggest that this part of the ice cap was larger than today until 7.8–7.2 cal kyr BP. Even today, the Drangajokull ice cap has a different behavior than the main ice caps in Iceland, characterized by a very low Glaciation Limit. Because palaeoclimatic proxies show an early-mid Holocene temperature optimum in this part of Iceland, we suggest that the persistence of Drangajokull into the early Holocene and, possibly, also the entire Holocene was due to high winter precipitation.
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Early to middle Holocene valley Glaciations on northernmost Greenland
Quaternary Science Reviews, 2010Co-Authors: Per Möller, Anders Schomacker, Nicolaj K. Larsen, Kurt H. Kjær, Svend Funder, Henriette Linge, Derek FabelAbstract:Abstract This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18–22 cal ka BP) into the Holocene. It records the history of a shelf-based Glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine Limit formed at ∼45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from on-lapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14 C dating results, the youngest ice advance phase can be narrowed down to 14 C ages between ∼5.5–5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of ∼2500 years during which the north coast of Greenland – as opposed to today – experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which, coupled to documented HTM cold reversals, caused a lowered Glaciation Limit, and led to a positive mass balance and subsequent ice advance.
Anders Schomacker - One of the best experts on this subject based on the ideXlab platform.
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The Drangajökull ice cap, northwest Iceland, persisted into the early-mid Holocene
Quaternary Science Reviews, 2016Co-Authors: Anders Schomacker, Skafti Brynjólfsson, Julie M. Andreassen, Esther Ruth Gudmundsdóttir, Jesper V. Olsen, Bent Vad Odgaard, Lena Håkansson, Ólafur Ingólfsson, Nicolaj K. LarsenAbstract:Abstract Most glaciers and ice caps in Iceland experienced rapid deGlaciation in the early Holocene, reaching a minimum extent during the Holocene Thermal Maximum. Here we present evidence of the Holocene glacial history from lake sediment cores retrieved from seven threshold lakes around the Drangajokull ice cap in the Vestfirðir peninsula, NW Iceland. The sediment cores show on/off signals of glacial meltwater activity, as minerogenic material deposited from glacial meltwater alternates with organic-rich material (gyttja) deposited without glacial meltwater. We base the chronology of the sediment cores on 14C ages and geochemical identification of key tephra layers with known ages. A 25-cm thick layer of the Saksunarvatn tephra in Lake Skorarvatn indicates that the northern part of the ice cap had reached a similar size as today or was smaller already by 10.2 cal kyr BP. However, 14C ages of lake sediment cores from the highlands southeast of Drangajokull suggest that this part of the ice cap was larger than today until 7.8–7.2 cal kyr BP. Even today, the Drangajokull ice cap has a different behavior than the main ice caps in Iceland, characterized by a very low Glaciation Limit. Because palaeoclimatic proxies show an early-mid Holocene temperature optimum in this part of Iceland, we suggest that the persistence of Drangajokull into the early Holocene and, possibly, also the entire Holocene was due to high winter precipitation.
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Early to middle Holocene valley Glaciations on northernmost Greenland
Quaternary Science Reviews, 2010Co-Authors: Per Möller, Anders Schomacker, Nicolaj K. Larsen, Kurt H. Kjær, Svend Funder, Henriette Linge, Derek FabelAbstract:Abstract This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18–22 cal ka BP) into the Holocene. It records the history of a shelf-based Glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine Limit formed at ∼45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from on-lapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14 C dating results, the youngest ice advance phase can be narrowed down to 14 C ages between ∼5.5–5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of ∼2500 years during which the north coast of Greenland – as opposed to today – experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which, coupled to documented HTM cold reversals, caused a lowered Glaciation Limit, and led to a positive mass balance and subsequent ice advance.
Nat Rutter - One of the best experts on this subject based on the ideXlab platform.
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Laurentide, cordilleran, and montane Glaciation in the western Peace River — Grande Prairie region, Alberta and British Columbia, Canada
Quaternary International, 1996Co-Authors: Norm Catto, David G. E. Liverman, Peter Bobrowsky, Nat RutterAbstract:Abstract Geological investigations over the last decade in the western Peace River-Grande Prairie district of northwestern Alberta and northeastern British Columbia have provided important chronostratigraphic information regarding Laurentide, Cordilleran and Montane Quaternary glacial events. Numerous 14 C age determinations, as well as stratigraphic and sedimentological analyses of numerous exposures, indicate that this area was first glaciated by Cordilleran ice sometime before the Late Wisconsinan. During the Late Wisconsinan, ca. 22,000–14,000 BP, Laurentide glacier ice covered much of the area. Between approximately 15,000 and 10,000 BP, Montane ice affected only the western part of the Peace region. There is no evidence for synchroneity of the ice advances and, therefore, no evidence for ice coalescence in this region. The resultant ‘ice-free-corridor’ was most likely a laterally fluctuating zone which existed during a several thousand year period in the Late Pleistocene. Climatic conditions along the ‘corridor’ during this period were probably unfavorable for human migration, but adequate for some plants and small animals. Numerous isolated areas along the western foothills of the northern Rocky Mountains, west of the Laurentide Glaciation Limit, were never glaciated during the Late Wisconsinan.
Per Möller - One of the best experts on this subject based on the ideXlab platform.
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Early to middle Holocene valley Glaciations on northernmost Greenland
Quaternary Science Reviews, 2010Co-Authors: Per Möller, Anders Schomacker, Nicolaj K. Larsen, Kurt H. Kjær, Svend Funder, Henriette Linge, Derek FabelAbstract:Abstract This paper presents the glacial stratigraphy and palaeoenvironmental evolution around Constable Bugt, Johannes V. Jensen Land, located on the north coast of Greenland. This is a land of extreme climate: polar desert conditions and a coast bound by a permanent sea ice cover. Our data covers the period from the Last Glacial Maximum (LGM, 18–22 cal ka BP) into the Holocene. It records the history of a shelf-based Glaciation with ice flowing eastward along the coast as well as two local valley glacier advances from the south during the Holocene. With ice on the coastal plain during the LGM, glaciolacustrine basins formed in marginal positions and in ice-dammed valleys to the south into the mountainous area of Peary Land. With the break-up of shelf-based ice there was a gradual marine inundation at which the marine Limit formed at ∼45 m a.s.l. This initial early Holocene ice advance from the south formed prominent valley mouth moraines, especially in Sifs valley. Here, both glaciolacustrine and marine sediments were remoulded and/or dislocated as thrust blocks into a moraine ridge spanning more than 1 km in width and >60 m in height. Radiocarbon ages of sediments incorporated in this moraine, as well as from on-lapping sediments, suggest that the moraine formed between 9.6 and 6.3 cal ka BP. Based on 14 C dating results, the youngest ice advance phase can be narrowed down to 14 C ages between ∼5.5–5.0 cal ka BP. The recorded ice advances took place during the Holocene Thermal Maximum (HTM) for North Greenland, the last one close to the beginning of the Neoglacial cooling. During the HTM we have recorded a period of ∼2500 years during which the north coast of Greenland – as opposed to today – experienced an absence to very restricted occurrence of land-fast or multi-year sea ice. This observation can be explained by the altitudinal and temporal distribution of beach-ridge complexes that must have formed by wave action and thus requiring at least partial open-water conditions. With a moisture source at hand, we propose that this lead to enhanced precipitation in the near-coastal areas which, coupled to documented HTM cold reversals, caused a lowered Glaciation Limit, and led to a positive mass balance and subsequent ice advance.