Timing and extent of plio-pleistocene glaciations in north-western canada and east-central alaska

Duk-Rodkin, A; Barendregt, René W.; Froese, Duane G.; Weber, Florence R.; Enkin, R. J.; Smith, I R; Zazula, Grant D.; Waters, Pamela; Klassen, R. A.

doi:10.1016/s1571-0866(04)80206-9

Cited by 44 publications

(48 citation statements)

References 45 publications

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“…1). Nevertheless, parts of the YCP escaped Quaternary glaciations entirely Duk-Rodkin et al, 2004). The LIS extended into the study area slightly west of Herschel Island, across what is now the modern Firth River (Mackay, 1959;Rampton, 1982;Fig.…”

Section: Study Areamentioning

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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Section: Study Areamentioning

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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“…The LIS most likely blocked direct northern drainage into the Beaufort Sea, resulting in a drainage diversion that forced LIS meltwater and local drainage southward up the Babbage River and its confluences. Similarly, in the central Yukon, the LIS impounded the eastward drainage of the paleo-Porcupine River at McDougal Pass (e.g., Duk-Rodkin and Hughes, 1994) and caused westward drainage diversion into the Yukon River (e.g., Duk-Rodkin et al, 2004). The southern slopes of the British Mountains all belonged to the paleo-Porcupine watershed (Duk-Rodkin and Hughes, 1995); therefore, the Babbage River and its tributaries likely served as the major proglacial drainage path to the north along the oscillating LIS margin during the latest part of the full glacial.…”

Section: Late Glacial Drainage Diversion-initial Sedimentationmentioning

confidence: 99%

Late glacial and Holocene sedimentation, vegetation, and climate history from easternmost Beringia (northern Yukon Territory, Canada)

et al. 2012

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Beringian climate and environmental history are poorly characterized at its easternmost edge. Lake sediments from the northern Yukon Territory have recorded sedimentation, vegetation, summer temperature and precipitation changes since ~ 16 cal ka BP. Herb-dominated tundra persisted until ~ 14.7 cal ka BP with mean July air temperatures ≤ 5°C colder and annual precipitation 50 to 120 mm lower than today. Temperatures rapidly increased during the Bølling/Allerød interstadial towards modern conditions, favoring establishment ofBetula-Salixshrub tundra. Pollen-inferred temperature reconstructions recorded a pronounced Younger Dryas stadial in east Beringia with a temperature drop of ~ 1.5°C (~ 2.5 to 3.0°C below modern conditions) and low net precipitation (90 to 170 mm) but show little evidence of an early Holocene thermal maximum in the pollen record. Sustained low net precipitation and increased evaporation during early Holocene warming suggest a moisture-limited spread of vegetation and an obscured summer temperature maximum. Northern Yukon Holocene moisture availability increased in response to a retreating Laurentide Ice Sheet, postglacial sea level rise, and decreasing summer insolation that in turn led to establishment ofAlnus-Betulashrub tundra from ~ 5 cal ka BP until present, and conversion of a continental climate into a coastal-maritime climate near the Beaufort Sea.

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“…White et al 1997;Zhisheng et al 2001;Duk-Rodkin et al 2004;Praeg et al 2005;Stoker et al 2005). Tectonic and glacial activity, sea-level change and bottom currents caused substantial hiatuses at the continental margins (e.g.…”

Section: (A ) the Arctic Basin In The Pliocenementioning

confidence: 99%

“…This implies that sediment supply from the adjacent ice sheets on northeastern Greenland and in the northwestern Barents Sea almost simultaneously increased since 2.3-2.4 Ma. Duk-Rodkin et al (2004) reconstructed regional-scale Cordilleran and local ice caps in northern Alaska and the Beaufort-Mackenzie area between 2.6 and 2.9 Ma. IRD deposition started in the North Pacific at 2.73 Ma (e.g.…”

Section: (B ) Glaciation History Of the Circum-arctic Continentsmentioning

confidence: 99%

Pliocene palaeoceanography of the Arctic Ocean and subarctic seas

Matthießen

Knies

Vogt

et al. 2008

Phil. Trans. R. Soc. A.

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The Pliocene is important in the geological evolution of the high northern latitudes. It marks the transition from restricted local-to extensive regional-scale glaciations on the circum-Arctic continents between 3.6 and 2.4 Ma. Since the Arctic Ocean is an almost land-locked basin, tectonic activity and sea-level fluctuations controlled the geometry of ocean gateways and continental drainage systems, and exerted a major influence on the formation of continental ice sheets, the distribution of river run-off, and the circulation and water mass characteristics in the Arctic Ocean. The effect of a water mass exchange restricted to the Bering and Fram Straits on the oceanography is unknown, but modelling experiments suggest that this must have influenced the Atlantic meridional overturning circulation. Cold conditions associated with perennial sea-ice cover might have prevailed in the central Arctic Ocean throughout the Pliocene, whereas colder periods alternated with warmer seasonally ice-free periods in the marginal areas. The most pronounced oceanographic change occurred in the Mid-Pliocene when the circulation through the Bering Strait reversed and low-salinity waters increasingly flowed from the North Pacific into the Arctic Ocean. The excess freshwater supply might have facilitated sea-ice formation and contributed to a decrease in the Atlantic overturning circulation.

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Timing and extent of plio-pleistocene glaciations in north-western canada and east-central alaska

Cited by 44 publications

References 45 publications

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

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

Late glacial and Holocene sedimentation, vegetation, and climate history from easternmost Beringia (northern Yukon Territory, Canada)

Pliocene palaeoceanography of the Arctic Ocean and subarctic seas

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