Stratigraphy and palaeoenvironments of Richards Island and the eastern Beaufort Continental Shelf during the last glacial‐interglacial cycle

Murton, Julian B.

doi:10.1002/ppp.647

Cited by 38 publications

(38 citation statements)

References 75 publications

(121 reference statements)

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“…Input of sea spray is only relevant during the open-water season so that a prolonged ice cover during the late Pleistocene (Nørgaard-Pedersen et al, 2003;Bradley and England, 2008) should have further reduced the influx of sea salt. Additionally, sustained dry conditions (Carter, 1981;Alfimov and Berman, 2001;Murton, 2009) probably increased eolian input of terrestrial material into ice wedges, which is then directly mirrored in the hydrochemical signature.…”

Section: Carbon Sequestration and Origin In Relation To Inorganic Geomentioning

confidence: 99%

Dissolved organic carbon (DOC) in Arctic ground ice

et al. 2015

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Abstract. Thermal permafrost degradation and coastal erosion in the Arctic remobilize substantial amounts of organic carbon (OC) and nutrients which have accumulated in late Pleistocene and Holocene unconsolidated deposits. Permafrost vulnerability to thaw subsidence, collapsing coastlines and irreversible landscape change are largely due to the presence of large amounts of massive ground ice such as ice wedges. However, ground ice has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements which are important for ecosystems and carbon cycling. Here we show, using biogeochemical data from a large number of different ice bodies throughout the Arctic, that ice wedges have the greatest potential for DOC storage, with a maximum of 28.6 mg L −1 (mean: 9.6 mg L −1 ). Variation in DOC concentration is positively correlated with and explained by the concentrations and relative amounts of typically terrestrial cations such as Mg 2+ and K + . DOC sequestration into ground ice was more effective during the late Pleistocene than during the Holocene, which can be explained by rapid sediment and OC accumulation, the prevalence of more easily degradable vegetation and immediate incorporation into permafrost. We assume that pristine snowmelt is able to leach considerable amounts of well-preserved and highly bioavailable DOC as well as other elements from surface sediments, which are rapidly frozen and stored in ground ice, especially in ice wedges, even before further degradation. We found that ice wedges in the Yedoma region represent a significant DOC (45.2 Tg) and DIC (33.6 Tg) pool in permafrost areas and a freshwater reservoir of 4200 km 2 . This study underlines the need to discriminate between particulate OC and DOC to assess the availability and vulnerability of the permafrost carbon pool for ecosystems and climate feedback upon mobilization.

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Section: Carbon Sequestration and Origin In Relation To Inorganic Geomentioning

confidence: 99%

Dissolved organic carbon (DOC) in Arctic ground ice

et al. 2015

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“…Higher ion contents of marine-related elements in unit B further support this interpretation (Table 5). In contrast to the large sand seas and dune fields in Northern Alaska and the Tuktoyaktuk Coastlands (Carter, 1981;Murton, 2009), substantial areas along the YCP may have been protected from eolian transport by cohesive tills (Bateman and Murton, 2006). Moreover, the source area for eolian sediment supply was probably smaller than other parts of the Arctic Coastal Plain due to the narrow shelf adjacent to the Mackenzie Trough that persisted during the sea level lowstand of the LGM (Fig.…”

Section: Depositional Environmentmentioning

confidence: 99%

“…Rampton (1982Rampton ( , 1988 argued that higher summer temperatures and increased effective moisture led to the onset of thermokarst on the YCP and the Tuktoyaktuk Coastlands, peaking between 12.1 and 10.3 cal ka BP. Ice-wedge growth would have been reduced or absent (Mackay, 1992;Murton and Bateman, 2007;Murton, 2009) during such a period of near-surface permafrost thaw and thermokarst lake development. Active-layer deepening to as much as 1.5 to 3.0 m below the modern surface is recorded on Herschel Island (Figs.…”

Section: Thermokarst and Thaw Unconformitymentioning

confidence: 99%

Eastern Beringia and beyond: Late Wisconsinan and Holocene landscape dynamics along the Yukon Coastal Plain, Canada

Fritz

Wetterich

Schirrmeister

et al. 2012

Palaeogeography, Palaeoclimatology, Palaeoecology

118

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Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compare the late glacial and Holocene landscape development on both sides of the former ice margin based on permafrost sequences and ground ice. Analyses at these sites involved a multi-proxy approach including: sedimentology, cryostratigraphy, palaeoecology of ostracods, stable water isotopes in ground ice, hydrochemistry, and AMS radiocarbon and infrared stimulated luminescence (IRSL) dating. AMS and IRSL age determinations yielded full glacial ages at Komakuk Beach that is the northeastern limit of ice-free Beringia. Herschel Island to the east marks the Late Wisconsinan limit of the northwest Laurentide Ice Sheet and is composed of ice-thrust sediments containing plant detritus as young as 16.2 cal ka BP that might provide a maximum age on ice arrival. Late Wisconsinan ice wedges with sediment-rich fillings on Herschel Island are depleted in heavy oxygen isotopes (mean δ 18O of − 29.1‰); this, together with low dexcess values, indicates colder-than-modern winter temperatures and probably reduced snow depths. Grain-size distribution and fossil ostracod assemblages indicate that deglaciation of the Herschel Island icethrust moraine was accompanied by alluvial, proluvial, and eolian sedimentation on the adjacent unglaciated Yukon Coastal Plain until~11 cal ka BP during a period of low glacio-eustatic sea level. The late glacial-Holocene transition was marked by higher-than-modern summer temperatures leading to permafrost degradation that began no later than 11.2 cal ka BP and caused a regional thaw unconformity. Cryostructures and ice wedges were truncated while organic matter was incorporated and soluble ions were leached in the thaw zone. Thermokarst activity led to the formation of ice-wedge casts and deposition of thermokarst lake sediments. These were subsequently covered by rapidly accumulating peat during the early Holocene Thermal Maximum. A rising permafrost table, reduced peat accumulation, and extensive ice-wedge growth resulted from climate cooling starting in the middle Holocene until the late 20th century. The reconstruction of palaeolandscape dynamics on the Yukon Coastal Plain and the eastern Beringian edge contributes to unraveling the linkages between ice sheet, ocean, and permafrost that have existed since the Late Wisconsinan.

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“…12b) at the onset of the Holocene. Ice-wedge growth would have been reduced or absent (Mackay, 1992;Murton and Bateman, 2007;Murton, 2009) during such a period of near-surface permafrost thaw and thermokarst lake development. Active-layer deepening to as much as 1.5e3.0 m below the modern surface is recorded on Herschel Island and in the western Canadian Arctic by truncated ice wedges and a prominent unconformity (Fig.…”

Section: Early Holocene Iwp Degradation and Thermokarstmentioning

confidence: 99%

Holocene ice-wedge polygon development in northern Yukon permafrost peatlands (Canada)

Fritz

Wolter

Rudaya

et al. 2016

Quaternary Science Reviews

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a b s t r a c tIce-wedge polygon (IWP) peatlands in the Arctic and Subarctic are extremely vulnerable to climatic and environmental change. We present the results of a multidisciplinary paleoenvironmental study on IWPs in the northern Yukon, Canada. High-resolution laboratory analyses were carried out on a permafrost core and the overlying seasonally thawed (active) layer, from an IWP located in a drained lake basin on Herschel Island. In relation to 14 Accelerator Mass Spectrometry (AMS) radiocarbon dates spanning the last 5000 years, we report sedimentary data including grain size distribution and biogeochemical parameters (organic carbon, nitrogen, C/N ratio, d 13 C), stable water isotopes (d 18 O, dD), as well as fossil pollen, plant macrofossil and diatom assemblages. Three sediment units (SUs) correspond to the main stages of deposition (1) in a thermokarst lake (SU1: 4950 to 3950 cal yrs BP), (2) during transition from lacustrine to palustrine conditions after lake drainage (SU2: 3950 to 3120 cal yrs BP), and (3) in palustrine conditions of the IWP field that developed after drainage (SU3: 3120 cal yrs BP to 2012 CE). The lacustrine phase (pre 3950 cal yrs BP) is characterized by planktonic-benthic and pioneer diatom species indicating circumneutral waters, and very few plant macrofossils. The pollen record has captured a regional signal of relatively stable vegetation composition and climate for the lacustrine stage of the record until 3950 cal yrs BP. Palustrine conditions with benthic and acidophilic diatom species characterize the peaty shallow-water environments of the low-centered IWP. The transition from lacustrine to palustrine conditions was accompanied by acidification and rapid revegetation of the lake bottom within about 100 years. Since the palustrine phase we consider the pollen record as a local vegetation proxy dominated by the plant communities growing in the IWP. Ice-wedge cracking in water-saturated sediments started immediately after lake drainage at about 3950 cal yrs BP and led to the formation of an IWP mire. Permafrost aggradation through downward closed-system freezing of the lake talik is indicated by the stable water isotope record. The originally submerged IWP center underwent gradual drying during the past 2000 years. This study highlights the sensitivity of permafrost landscapes to climate and environmental change throughout the Holocene.

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Stratigraphy and palaeoenvironments of Richards Island and the eastern Beaufort Continental Shelf during the last glacial‐interglacial cycle

Cited by 38 publications

References 75 publications

Dissolved organic carbon (DOC) in Arctic ground ice

Dissolved organic carbon (DOC) in Arctic ground ice

Eastern Beringia and beyond: Late Wisconsinan and Holocene landscape dynamics along the Yukon Coastal Plain, Canada

Holocene ice-wedge polygon development in northern Yukon permafrost peatlands (Canada)

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