Svalbard glaciers re‐advanced during the Pleistocene–Holocene transition

The lower Borgarfjörður region, western Iceland, has been central to the reconstructions of the dynamics and collapse of the Icelandic Ice Sheet during the deglaciation. Here, extensive stratigraphical sections and landforms provide a rare opportunity to study past glacier dynamics in this part of Iceland. Previous studies reveal that a large outlet glacier in Borgarfjörður advanced during the Late Weichselian resulting in large‐scale deformation of glaciomarine sediments and the formation of a series of ice‐marginal moraines. However, the events recorded by these sediments and landforms are poorly constrained in time. We present and discuss 22 new radiocarbon dates in the context of recent reconstructions of the regional glacier dynamics in order to constrain the timing of the glacier oscillations. The results show that a dynamic, marine‐terminating glacier advanced out of Borgarfjörður sometime after c. 13.0 cal. ka BP, resulting in the formation of an extensive moraine complex. The timing indicates that the advance occurred during climate cooling and widespread glacier expansions within the Younger Dryas. Followed by the first initial advance, the glacier exhibited at least five re‐advances punctuated by phases of retreat. Each re‐advance terminated proximal (within 5 km) to the outermost moraine complex although the extent of periodic retreat and the exact timing of these oscillations are unknown. All these phases of re‐advance occurred prior to the onset of the Holocene (around 11.7 cal. ka BP), during which marine fauna re‐colonized the area and the Borgarfjörður glacier retreated from the moraines. During the Early Holocene (sometime after c. 11.3 cal. ka BP), the Borgarfjörður glacier re‐advanced to a position within ~5 km of the YD ice limit. This is the first recorded Early Holocene large‐scale glacier advance in western Iceland and suggests that glacier expansion in this region coincided with widespread advances elsewhere in Iceland.

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“…) that appear to be asynchronous and most likely result from dynamic instability during the deglaciation (Farnsworth et al . ).…”

Section: Revised Late Weichselian Glaciation History Of the Lower Bormentioning

confidence: 97%

“…That would be in agreement with glacier records in Svalbard, which show widespread re‐advances during the Early Holocene (Lønne ; Farnsworth et al . ; Larsen et al . ) that appear to be asynchronous and most likely result from dynamic instability during the deglaciation (Farnsworth et al .…”

Section: Revised Late Weichselian Glaciation History Of the Lower Bormentioning

confidence: 99%

Refining the history of Younger Dryas and Early Holocene glacier oscillations in the Borgarfjörður region, western Iceland

Sigfúsdóttir

Benediktsson

2019

Boreas

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“…in de Geerbukta on northeast Spitsbergen, 60 km west of Palanderbukta, yielded a median age of 10.5 cal. kyr BP 25 . The RSL curves from Lady Franklinfjorden and Svartknausflya are the only other long RSL reconstructions from Nordaustlandet 5,6 .…”

Section: Discussionmentioning

confidence: 99%

“…This study from Wahlenbergfjorden highlights the complex spatial variability in glacier response during the deglaciation and early Holocene warming. Farnsworth et al 25 showed that a nearby major outlet glacier, Gullfaksebreen, in De Geerbukta at the west side of the Hinlopen Strait advanced in the early Holocene, a period characterized by mild climate and peak insolation (Fig. 1).…”

Section: Discussionmentioning

confidence: 99%

“…Previous lake sediment studies from Nordaustlandet have focused on palaeoecological and palaeoclimatic reconstructions [10][11][12]19 , and have not been targeting proglacial threshold lakes that potentially contain glacial on/off signals [20][21][22] . Data highlighting Holocene glacier variations on Svalbard are important to understanding the observed recent ice loss and place it in a long-term perspective [22][23][24][25][26] . The aim of this study is (1) to reconstruct the late Holocene glacier fluctuations of Etonbreen, based on threshold lake sediment cores from Kløverbladvatna, and (2) to decipher the postglacial relative sea level changes in Palanderbukta, Wahlenbergfjorden, based on radiocarbon dating of raised beach ridges.…”

mentioning

confidence: 99%

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Postglacial Relative Sea Level Change and Glacier Activity in the Early and Late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard

Schomacker¹,

Farnsworth²,

Inǵólfsson³

et al. 2019

Geological Society of America Abstracts With Programs

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Postglacial relative sea level change and glacier activity in the early and late holocene: Wahlenbergfjorden, nordaustlandet, svalbard. Scientific Reports, 9(1), 1-13. Sediment cores from Kløverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kløverbladvatna became isolated from Wahlenbergfjorden c. 5.4 cal. kyr BP due to glacioisostatic rebound. During the Late Holocene, laminated clayey gyttja from lacustrine organic production and surface runoff from the catchment accumulated in the lake. The lacustrine sedimentary record suggests that meltwater only spilled over the threshold at the peak of the surge of Etonbreen in AD 1938. Hence, we suggest that this was the largest extent of Etonbreen in the (mid-late) Holocene. In Palanderbukta, a tributary fjord to Wahlenbergfjorden, raised beaches were surveyed and organic material collected to determine the age of the beaches and reconstruct postglacial relative sea level change. The age of the postglacial raised beaches ranges from 10.7 cal. kyr BP at 50 m a.s.l. to 3.13 cal. kyr BP at 2 m a.s.l. The reconstructed postglacial relative sea level curve adds valuable spatial and chronological data to the relative sea level record of Nordaustlandet.Nordaustlandet is a key locality for understanding the glacial history of Svalbard. Recent studies suggest that during the Last Glacial Maximum (LGM), ice domes in the Svalbard-Barents Sea Ice Sheet were centered over the southern opening of the Hinlopen Strait and Nordaustlandet 1-3 . This is not compatible with postglacial isostatic rebound evidence reconstructed from raised beaches around the Svalbard archipelago, which suggests a maximum LGM ice load over Kong Karls Land to the southeast of Nordaustlandet 4,5 . The location of LGM ice domes, timing, and implications for ice sheet dynamics is still debated 6,7 . Postglacial relative sea level changes on Nordaustlandet and eastern Spitsbergen are not well constrained in time and space. Blake 8 reconstructed the relative sea level history of Lady Franklinfjorden in northwest Nordaustlandet, and suggested a Late Weichselian-Holocene marine limit of at least 50 m above high tide (a.h.t.). A study 9 from Svartknausflya at the south coast of Nordaustlandet suggested a marine limit of more than 70 m a.h.t. Marine isolation ages from lakes on Nordaustlandet provide ancillary information about the postglacial relative sea level changes [10][11][12] .At present, about 80% of Nordaustlandet is glaciated, mainly by the two ice caps Austfonna (7800 km 2 ) and the smaller Vestfonna (2455 km 2 ) 1,13,14 . The location between these two ice caps makes the inner part of Wahlenbergfjorden an important site for studying Holocene glacier variations. Flink et al. 15 suggested that the Wahlenbe...

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Glacier decay boosts the formation of new Arctic coastal environments—Perspectives from Svalbard

Kavan

2023

Land Degrad Dev

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The consequences of accelerating climatic warming on Arctic landscape evolution are far-reaching. In Svalbard, glaciers are rapidly retreating after the Little Ice Age, which leads to exposing new coastal landscapes from marine-terminating glaciers. Precise quantification of these changes was limited until the complete dataset of Svalbard glacier outlines from 1930's was made available. Here, we analyse the new Svalbard glacier change inventory data and demonstrate that glacier retreat led to a major shift from marine-terminating towards land-based glaciers in the last century. This retreat also led to the formation of 922.9 km of new coastline since 1930's creating pristine landscapes governed by paraglacial processes and sediment-rich nearshore fjord environments. Recent palaeogeographical reconstructions suggest that such a mode of coastal evolution was dominant over the extended periods of the Holocene. Transitions from marine-terminating to land-based glaciers have significant implications for fjord circulation, biological production, the state of marine ecosystems, biogeochemical cycles between land and seas and the CO 2 budget in coastal waters.

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Svalbard glaciers re‐advanced during the Pleistocene–Holocene transition

Cited by 23 publications

References 65 publications

Refining the history of Younger Dryas and Early Holocene glacier oscillations in the Borgarfjörður region, western Iceland

Refining the history of Younger Dryas and Early Holocene glacier oscillations in the Borgarfjörður region, western Iceland

Postglacial Relative Sea Level Change and Glacier Activity in the Early and Late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard

Glacier decay boosts the formation of new Arctic coastal environments—Perspectives from Svalbard

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