Late Glacial and Holocene Glacier and Vegetation Fluctuations at Little Swift Lake, Southwestern Alaska, U.S.A

Axford, Yarrow; Kaufman, Darrell S.

doi:10.1657/1523-0430(2004)036[0139:lgahga]2.0.co;2

Cited by 18 publications

(17 citation statements)

References 39 publications

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“…Concentrations of chironomid remains, which were low during the YD interval, are *10 times higher in the oldest Holocene sample. The pronounced increase in OM content following the YD is similar to that found in other lake sediments in the Ahklun Mountains, including Nimgun Lake (Hu et al 2002), Arolik Lake , and Little Swift Lake (Axford and Kaufman 2004). Isotopic and paleoecological evidence indicate that the increase in OM content coincides with an increase in regional temperature and moisture (Hu et al 2006).…”

Section: Discussionsupporting

confidence: 77%

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

et al. 2012

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Sediment cores from Lone Spruce Pond (60.007°N, 159.143°W), southwestern Alaska, record paleoenvironmental changes during the global Last Glacial Maximum (LGM), and during the last 14,500 calendar years BP (14.5 cal ka). We analyzed the abundance of organic matter, biogenic silica, carbon, and nitrogen, and the isotope ratios of C and N, magnetic susceptibility, and grain-size distribution of bulk sediment, abundance of alder shrub (Alnus) pollen, and midge (Chironomidae and Chaoboridae) assemblages in a 4.7-m-long sediment sequence from the depocenter at 22 m water depth. The basal unit contains macrofossils dating to 25-21 cal ka (the global LGM), and is interpreted as glacial-lacustrine sediment. The open water requires that the outlet of the Ahklun Mountain ice cap had retreated to within 6 km of the range crest. In addition to cladocerans and diatoms, the glacial-lacustrine mud contains chironomids consistent with deep, oligotrophic conditions; several taxa associated with relatively warm conditions are present, suggestive of relative warmth during the global LGM. The glacial-lacustrine unit is separated from the overlying non-glacial lake sediment by a possible disconformity, which might record a readvance of glacier ice. Non-glacial sediment began accumulating around 14.5 cal ka, with high flux of mineral matter and fluctuating physical and biological properties through the global deglacial period, including a reversal in biogenic-silica (BSi) content during the Younger Dryas (YD). During the global deglacial interval, the d 13 C values of lake sediment were higher relative to other periods, consistent with low C:N ratios (8), and suggesting a dominant atmospheric CO 2 source of C for phytoplankton. Concentrations of This is one of 18 papers published in a special issue edited by Darrell Kaufman, and dedicated to reconstructing Holocene climate and environmental change from Arctic lake sediments. aquatic faunal remains (chironomids and Cladocera) were low throughout the deglacial interval, diversity was low and warm-indicator taxa were absent. Higher production and air temperatures are inferred following the YD, when bulk organic-matter (OM) content (LOI 550°C) increased substantially and permanently, from 10 to 30 %, a trend paralleled by an increase in C and N abundance, an increase in C:N ratio (to about 12), and a decrease in d 13 C of sediment. Post-YD warming is marked by a rapid shift in the midge assemblage. Between 8.9 and 8.5 cal ka, Alnus pollen tripled (25-75 %), followed by the near-tripling of BSi (7-19 %) by 8.2 cal ka, and d 15 N began a steady rise, reflecting the buildup of N and an increase in denitrification in soils. Several chironomid taxa indicative of relatively warm conditions were present throughout the Holocene. Quantitative chironomidbased temperature inferences are complicated by the expansion of Alnus and resulting changes in lake nutrient status and production; these changes were associated with an abrupt increase in cladoceran abundance and persistent shift in the chironomid...

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Section: Discussionsupporting

confidence: 77%

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

et al. 2012

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“…However, recent palaeoclimate research in the Seymour-Belize Inlet Complex (SBIC) of the central mainland coast of British Columbia (BC) documents the transition from an early Holocene xerothermic climate to cooler and moister conditions ca. 1000-1700 a prior to more southern locations, but contemporaneous with sites in the southwestern Yukon, coastal Alaska and parts of northern BC (Cwynar, 1988;Hansen and Engstrom, 1996;Lacourse and Gajewski, 2000;Spooner et al, 1997Spooner et al, , 2002Axford and Kaufman, 2004;Galloway et al, 2007). This pattern of climate asynchrony suggests that early Holocene dynamics in the Aleutian Low (AL) pressure system were an important influence on the climate of this region Galloway et al, 2007).…”

Section: Introductionmentioning

confidence: 91%

“…When the AL is on average more eastward and/or stronger than usual, a climate characterised by relatively cool summers and mild winters with high precipitation is experienced in coastal BC. This is in part because (Barnosky, 1981); (2) Lake Washington (Leopold et al, 1982); (3) Crocker Lake and Cedar Swamp (McLachlan and Brubaker, 1995); (4) Kirk Lake (Cwynar, 1987); (5) East Sooke Fen (Brown and Hebda, 2002); (6) Pixie Lake (Brown and Hebda, 2002); (7) Walker Lake (Brown and Hebda, 2003); (8) Whyac Lake (Brown and Hebda, 2002); (9) Saanich Inlet (Pellatt et al, 2001); (10) Porphory Lake (Brown and Hebda, 2003); (11) Marion and Surprise Lakes (Mathewes, 1973;Mathewes and Heusser, 1981); (12) Pinecrest and Squeah Lakes (Mathewes and Rouse, 1975); (13) Brooks Peninsula (Hebda, 1997); (14) Misty Lake (Lacourse, 2005); (15) Bear Cove Bog (Hebda, 1983); (16) (Quickfall, 1987); (17) West Side Pond ; (18) SC1 Pond (Pellatt and Mathewes, 1997); (19) Louise Pond (Pellatt and Mathewes, 1994); (20) Shangri-La Bog (Pellatt and Mathewes, 1997);(21, 22) (Warner, 1984);(23, 24) (Quickfall, 1987); (25) Dogfish Bank ; (26) (Banner et al, 1983); (27) Diana Lake Bog (Turunen and Turunen, 2003); (28) Skinny Lake (Spooner et al, 2002); (29) Susie Lake (Spooner et al, 1997); (30) Pyramid Lake ; (31) Pleasant Island (Hansen and Engstrom, 1996); (32) Waterdevil Lake (Spear and Cwynar, 1997); (33) Kettlehole Pond (Cwynar, 1988); (34) Icy Cape (Peteet, 1986); (35) Little Swift Lake …”

Section: Climatementioning

confidence: 99%

Postglacial vegetation and climate dynamics in the Seymour‐Belize Inlet Complex, central coastal British Columbia, Canada: palynological evidence from Tiny Lake

Galloway

Doherty

Patterson

et al. 2009

J Quaternary Science

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A pollen-based study from Tiny Lake in the Seymour-Belize Inlet Complex of central coastal British Columbia, Canada, permits an evaluation of the dynamic response of coastal temperate rainforests to postglacial climate change. Open Pinus parklands grew at the site during the early Lateglacial when the climate was cool and dry, but more humid conditions in the later phases of the Lateglacial permitted mesophytic conifers to colonise the region. Early Holocene conditions were warmer than present and a successional mosaic of Tsuga heterophylla and Alnus occurred at Tiny Lake. Climate cooling and moistening at 8740 AE 70 14 C a BP initiated the development of closed, late successional T. heterophylla-Cupressaceae forests, which achieved modern character after 6860 AE 50 14 C a BP, when a temperate and very wet climate became established. The onset of early Holocene climate cooling and moistening at Tiny Lake may have preceded change at more southern locations, including within the Seymour-Belize Inlet Complex, on a meso-to synoptic scale. This would suggest that an early Holocene intensification of the Aleutian Low pressure system was an important influence on forest dynamics in the Seymour-Belize Inlet Complex and that the study region was located near the southern extent of immediate influence of this semi-permanent air mass.

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“…1), were covered by the largest ice mass in western Alaska. The range has been the focus of Quaternary research in the last decade, and a detailed mid and late Quaternary glacial history has emerged through surficial mapping, and stratigraphic and lake core studies, coupled with a suite of geochronological methods Briner and Kaufman, 2000;Briner et al, 2001;Manley et al, 2001;Kaufman et al, 2001a,b;Briner et al, 2002;Kaufman et al, 2003;Axford and Kaufman, 2004;Levy et al, 2004). During the Late Pleistocene, the Ahklun Mountains hosted an ice cap over its east-central spine that expanded radially, extending farther to the south and west than to the north and east (Fig.…”

Section: Ahklun Mountainsmentioning

confidence: 99%

Late Pleistocene mountain glaciation in Alaska: key chronologies

Briner

Kaufman

2008

J Quaternary Science

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Moraine sequences of mountain glaciers can be used to infer spatial and temporal patterns of climate change across the globe. Alaska is an accessible high-latitude location in the Northern Hemisphere and contains a rich record of alpine glaciation. Here, we highlight the key chronologies from three mountain ranges in Alaska that reveal the timing and spatial extent of Late Pleistocene glaciation, and pay particular attention to age of the penultimate glaciation. The most extensive glacier advance of the last glaciation occurred prior to the last global glacial maximum. Cosmogenic exposure ages from moraine boulders in three sites spanning 800 km indicate that this penultimate advance most likely culminated during marine isotope stage (MIS) 4 or early MIS 3. During MIS 2, more limited glacier expansion generated multiple moraines that span from prior to the global Last Glacial Maximum (LGM) through the Lateglacial period. Glaciers retreated from their terminal positions ca. 27-25 ka in arctic Alaska and ca. 22-19 ka in southern Alaska. Moraines in at least two ranges date to 12-11 ka, indicating a glacial advance during the Younger Dryas period. Reconstructed equilibrium-line altitudes of both penultimate and MIS 2 glaciers were lowered only 300-600 mmuch less than elsewhere in the Americas. Alaska is documented to have been more arid during MIS 2, perhaps due in large part to the exposure of the Bering-Chukchi platform during eustatic sea-level lowering. The restricted ice extent is also consistent with the output of climate models that simulate a lack of significant summer cooling.

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Late Glacial and Holocene Glacier and Vegetation Fluctuations at Little Swift Lake, Southwestern Alaska, U.S.A

Cited by 18 publications

References 39 publications

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

Postglacial vegetation and climate dynamics in the Seymour‐Belize Inlet Complex, central coastal British Columbia, Canada: palynological evidence from Tiny Lake

Late Pleistocene mountain glaciation in Alaska: key chronologies

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