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

Darrell S Kaufman, Yarrow Axford, Scott R Anderson, Scott F. Lamoureux, Daniel E. Schindler, Ian R. Walker, Al Werner

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

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 δ 13C 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 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 δ 13C 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 δ 15N 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 chironomid-based 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 assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.

Original languageEnglish (US)
Pages (from-to)9-26
Number of pages18
JournalJournal of Paleolimnology
Volume48
Issue number1
DOIs
StatePublished - Jun 2012

Fingerprint

Last Glacial Maximum
Chironomidae
Picea
Younger Dryas
pond
silica
Alnus
lacustrine deposit
sediments
organic matter
sediment
pollen
Holocene
midges
eighteenth century
depocenter
ice cap
lakes
carbon nitrogen ratio
glacial deposit

Keywords

  • Alaska
  • Biogenic silica
  • Carbon and nitrogen isotopes
  • Lake Sediment
  • Magnetic susceptibility
  • Midges
  • Pollen
  • Quaternary paleoenvironments

ASJC Scopus subject areas

  • Aquatic Science
  • Earth-Surface Processes

Cite this

A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska. / Kaufman, Darrell S; Axford, Yarrow; Anderson, Scott R; Lamoureux, Scott F.; Schindler, Daniel E.; Walker, Ian R.; Werner, Al.

In: Journal of Paleolimnology, Vol. 48, No. 1, 06.2012, p. 9-26.

Research output: Contribution to journalArticle

Kaufman, Darrell S ; Axford, Yarrow ; Anderson, Scott R ; Lamoureux, Scott F. ; Schindler, Daniel E. ; Walker, Ian R. ; Werner, Al. / A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska. In: Journal of Paleolimnology. 2012 ; Vol. 48, No. 1. pp. 9-26.
@article{527cbf37191b41bba8d208cb2443ba53,
title = "A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska",
abstract = "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 δ 13C 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 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 δ 13C 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 δ 15N 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 chironomid-based 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 assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.",
keywords = "Alaska, Biogenic silica, Carbon and nitrogen isotopes, Lake Sediment, Magnetic susceptibility, Midges, Pollen, Quaternary paleoenvironments",
author = "Kaufman, {Darrell S} and Yarrow Axford and Anderson, {Scott R} and Lamoureux, {Scott F.} and Schindler, {Daniel E.} and Walker, {Ian R.} and Al Werner",
year = "2012",
month = "6",
doi = "10.1007/s10933-012-9607-4",
language = "English (US)",
volume = "48",
pages = "9--26",
journal = "Journal of Paleolimnology",
issn = "0921-2728",
publisher = "Springer Netherlands",
number = "1",

}

TY - JOUR

T1 - A multi-proxy record of the Last Glacial Maximum and last 14,500 years of paleoenvironmental change at Lone Spruce Pond, southwestern Alaska

AU - Kaufman, Darrell S

AU - Axford, Yarrow

AU - Anderson, Scott R

AU - Lamoureux, Scott F.

AU - Schindler, Daniel E.

AU - Walker, Ian R.

AU - Werner, Al

PY - 2012/6

Y1 - 2012/6

N2 - 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 δ 13C 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 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 δ 13C 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 δ 15N 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 chironomid-based 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 assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.

AB - 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 δ 13C 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 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 δ 13C 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 δ 15N 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 chironomid-based 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 assemblage. During the last 2,000 years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.

KW - Alaska

KW - Biogenic silica

KW - Carbon and nitrogen isotopes

KW - Lake Sediment

KW - Magnetic susceptibility

KW - Midges

KW - Pollen

KW - Quaternary paleoenvironments

UR - http://www.scopus.com/inward/record.url?scp=84861588108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84861588108&partnerID=8YFLogxK

U2 - 10.1007/s10933-012-9607-4

DO - 10.1007/s10933-012-9607-4

M3 - Article

VL - 48

SP - 9

EP - 26

JO - Journal of Paleolimnology

JF - Journal of Paleolimnology

SN - 0921-2728

IS - 1

ER -