Plant and Insect Fossils from the Mayo Indian Village Section (Central Yukon): New Data on Middle Wisconsinan Environments and Glaciation

Matthews, John V.; Schweger, Charles E.; Hughes, O L

doi:10.7202/032794ar

Cited by 36 publications

(15 citation statements)

References 29 publications

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“…Imuruk Lake pollen data from Colinvaux (1964); Koyukuk-11 data from Schweger (1982); Bluefish Basin pollen data from Lichti-Federovich (1974) and Schweger and Matthews (1985); Bluefish Basin insect data from Matthews etal., (1990). Colinvaux (1964); données de Koyukuk-11 de Schweger (1982); données polliniques de Bluefish Basin de Lichti-Federovich (1974) et de Schweger and Matthews (1985); données sur les insectes de Bluefish Basin de Matthews et al, (1990).…”

Section: Insect Paleoecologyunclassified

Paleoecology of an Interglacial Peat Deposit, Nuyakuk, Southwestern Alaska, U.S.A.

Elias¹,

Short²

2007

gpq

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This paper reports the presence of interglacial beetle and pollen assemblages within a Pleistocene peat deposit exposed along the Nuyakuk River of southwestern Alaska. The fossil beetle assemblages contain a number of species not previously identified from eastern Beringian fossil assemblages. The Nuyakuk interglacial deposits are exposed within a 6-m-high terrace along the river, about 4 km beyond the moraine of the penultimate glaciation. Interglacial peat lies within the lowermost meter of the bluff and is overlain by fluvial gravel and loess. Insect fossils were extracted from five peat samples, yielding sixty-seven identified beetle taxa. The insect faunal diversity of the Nuyakuk assemblages is comparable to that found in regional Holocene peat samples. In contrast to assemblages of similar age from interior eastern Beringia, the Nuyakuk fauna contains significant numbers of aquatic, hygrophilous and riparian taxa. Four pollen samples from the Nuyakuk site were analyzed, providing spectra dominated by a few taxa, notably Alnus, Betula, Picea, Gramineae, Cyperaceae, Filicales, and Sphagnum, suggesting a rich alder-birch shrub tundra not much different from the modern regional vegetation. The pollen and insect fossil records also suggest climatic conditions similar to modern.

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Section: Insect Paleoecologyunclassified

Paleoecology of an Interglacial Peat Deposit, Nuyakuk, Southwestern Alaska, U.S.A.

Elias¹,

Short²

2007

gpq

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“…Eisner, 1991;Vardy et al, 1997Vardy et al, , 1998Vardy et al, , 2000Eisner et al, 2003), and vertebrate and invertebrate palaeoecology (e.g. Matthews, 1975;Delorme et al, 1977;Nelson and Carter, 1987;Matthews et al, 1990;Zazula et al, 2009). However, most of these studies have been conducted at sites ( Fig.…”

Section: Introductionmentioning

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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“…The McConnell glaciation is firmly dated to OIS 2 (Late Wisconsin). Radiocarbon ages from wood and fossils underlying McConnell till indicate that the McConnell glaciation began after 29,600±300 14 C yr BP (Matthews et al, 1990), but glaciers did not advance into major valleys before 26,350±280 14 C yr BP (Jackson and Harington, 1991), and a fully developed CIS did not exist until after 23,900±1140 14 C yr BP (Lowdon and Blake, 1981). Published radiocarbon ages indicate that the St. Elias lobe of the CIS was in retreat by 13,660±180 14 C yr BP (Rampton, 1971) and the Selwyn lobe by 12,590±120 14 C yr BP (Ward, 1989) (Fig.…”

Section: The Cordilleran Ice Sheetmentioning

confidence: 99%

Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz

Stroeven

Fabel

Codilean

et al. 2010

Quaternary Science Reviews

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Plant and Insect Fossils from the Mayo Indian Village Section (Central Yukon): New Data on Middle Wisconsinan Environments and Glaciation

Cited by 36 publications

References 29 publications

Paleoecology of an Interglacial Peat Deposit, Nuyakuk, Southwestern Alaska, U.S.A.

Paleoecology of an Interglacial Peat Deposit, Nuyakuk, Southwestern Alaska, U.S.A.

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

Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz

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