Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas

Jürgen Mey; Mitch K. D'Arcy; Taylor F. Schildgen; David L. Egholm; Hella Wittmann; Manfred R. Strecker

doi:10.1016/j.quascirev.2020.106592

Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas

Jürgen Mey^*, Mitch K. D'Arcy, Taylor F. Schildgen, David L. Egholm, Hella Wittmann, Manfred R. Strecker

^*Corresponding author for this work

Department of Geoscience

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

6 Citations (Scopus)

Abstract

Recent developments in terrestrial cosmogenic nuclide (TCN) exposure dating and the reinterpretation of TCN boulder ages from moraines have improved our understanding of the glacial chronology in the Central Andes. According to these records, glacial advances throughout the region correlate with insolation-driven changes in the intensity of the South American Summer Monsoon and millennial-scale climate events such as Heinrich Stadials and the Younger Dryas. Quantifying the temperature and precipitation shifts during these events helps to constrain past moisture pathways and associated changes in atmospheric circulation patterns. Yet, particularly in the southern Central Andes, where a wealth of glacigenic landforms attests to formerly cooler and/or wetter conditions, the magnitudes of past temperature and precipitation changes are only loosely constrained at a few sites. Here, we present results from TCN-dated moraines combined with the reconstruction of former glaciers and paleolakes within the eastern sector of the southern Central Andes (24°–27°S) for the Last Glacial Maximum (LGM), Heinrich Stadial 1 (HS1), and the Younger Dryas (YD). We performed Monte-Carlo simulations with 2-dimensional models of ice flow and lake hydrology that are forced by a spatially-distributed surface energy balance model. Our results indicate that temperatures were 3.0–4.2 °C, 2.0–3.3 °C and 1.3–2.5 °C cooler during the LGM, HS1 and YD, respectively, in agreement with previous estimates elsewhere in the Central Andes. We find that temperature changes during the late glacial are compatible with sea-surface temperature anomalies derived from the tropical Atlantic. Precipitation was only 5–27% greater than today, which contrasts with larger anomalies reconstructed for the Bolivian part of the Andean Plateau (Altiplano). We attribute this discrepancy to the southerly position of our study region with respect to the Bolivian High, supporting the hypothesis that this atmospheric pressure system played a prominent role for South American Summer Monsoon dynamics during glacial episodes.

Original language	English
Article number	106592
Journal	Quaternary Science Reviews
Volume	248
ISSN	0277-3791
DOIs	https://doi.org/10.1016/j.quascirev.2020.106592
Publication status	Published - Nov 2020

Keywords

Bolivian high
Central andes
Exposure age dating
Glaciation
Heinrich stadial 1
Landslidedammed lake
Last glacial maximum
Monsoon
Moraines
Paleoclimatology
South America
Younger dryas

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10.1016/j.quascirev.2020.106592

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@article{7107ddf7cb794d42b5faca54a46f8400,

title = "Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas",

abstract = "Recent developments in terrestrial cosmogenic nuclide (TCN) exposure dating and the reinterpretation of TCN boulder ages from moraines have improved our understanding of the glacial chronology in the Central Andes. According to these records, glacial advances throughout the region correlate with insolation-driven changes in the intensity of the South American Summer Monsoon and millennial-scale climate events such as Heinrich Stadials and the Younger Dryas. Quantifying the temperature and precipitation shifts during these events helps to constrain past moisture pathways and associated changes in atmospheric circulation patterns. Yet, particularly in the southern Central Andes, where a wealth of glacigenic landforms attests to formerly cooler and/or wetter conditions, the magnitudes of past temperature and precipitation changes are only loosely constrained at a few sites. Here, we present results from TCN-dated moraines combined with the reconstruction of former glaciers and paleolakes within the eastern sector of the southern Central Andes (24°–27°S) for the Last Glacial Maximum (LGM), Heinrich Stadial 1 (HS1), and the Younger Dryas (YD). We performed Monte-Carlo simulations with 2-dimensional models of ice flow and lake hydrology that are forced by a spatially-distributed surface energy balance model. Our results indicate that temperatures were 3.0–4.2 °C, 2.0–3.3 °C and 1.3–2.5 °C cooler during the LGM, HS1 and YD, respectively, in agreement with previous estimates elsewhere in the Central Andes. We find that temperature changes during the late glacial are compatible with sea-surface temperature anomalies derived from the tropical Atlantic. Precipitation was only 5–27% greater than today, which contrasts with larger anomalies reconstructed for the Bolivian part of the Andean Plateau (Altiplano). We attribute this discrepancy to the southerly position of our study region with respect to the Bolivian High, supporting the hypothesis that this atmospheric pressure system played a prominent role for South American Summer Monsoon dynamics during glacial episodes.",

keywords = "Bolivian high, Central andes, Exposure age dating, Glaciation, Heinrich stadial 1, Landslidedammed lake, Last glacial maximum, Monsoon, Moraines, Paleoclimatology, South America, Younger dryas",

author = "J{\"u}rgen Mey and D'Arcy, {Mitch K.} and Schildgen, {Taylor F.} and Egholm, {David L.} and Hella Wittmann and Strecker, {Manfred R.}",

year = "2020",

month = nov,

doi = "10.1016/j.quascirev.2020.106592",

language = "English",

volume = "248",

journal = "Quaternary Science Reviews",

issn = "0277-3791",

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Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas. / Mey, Jürgen; D'Arcy, Mitch K.; Schildgen, Taylor F. et al.
In: Quaternary Science Reviews, Vol. 248, 106592, 11.2020.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas

AU - Mey, Jürgen

AU - D'Arcy, Mitch K.

AU - Schildgen, Taylor F.

AU - Egholm, David L.

AU - Wittmann, Hella

AU - Strecker, Manfred R.

PY - 2020/11

Y1 - 2020/11

N2 - Recent developments in terrestrial cosmogenic nuclide (TCN) exposure dating and the reinterpretation of TCN boulder ages from moraines have improved our understanding of the glacial chronology in the Central Andes. According to these records, glacial advances throughout the region correlate with insolation-driven changes in the intensity of the South American Summer Monsoon and millennial-scale climate events such as Heinrich Stadials and the Younger Dryas. Quantifying the temperature and precipitation shifts during these events helps to constrain past moisture pathways and associated changes in atmospheric circulation patterns. Yet, particularly in the southern Central Andes, where a wealth of glacigenic landforms attests to formerly cooler and/or wetter conditions, the magnitudes of past temperature and precipitation changes are only loosely constrained at a few sites. Here, we present results from TCN-dated moraines combined with the reconstruction of former glaciers and paleolakes within the eastern sector of the southern Central Andes (24°–27°S) for the Last Glacial Maximum (LGM), Heinrich Stadial 1 (HS1), and the Younger Dryas (YD). We performed Monte-Carlo simulations with 2-dimensional models of ice flow and lake hydrology that are forced by a spatially-distributed surface energy balance model. Our results indicate that temperatures were 3.0–4.2 °C, 2.0–3.3 °C and 1.3–2.5 °C cooler during the LGM, HS1 and YD, respectively, in agreement with previous estimates elsewhere in the Central Andes. We find that temperature changes during the late glacial are compatible with sea-surface temperature anomalies derived from the tropical Atlantic. Precipitation was only 5–27% greater than today, which contrasts with larger anomalies reconstructed for the Bolivian part of the Andean Plateau (Altiplano). We attribute this discrepancy to the southerly position of our study region with respect to the Bolivian High, supporting the hypothesis that this atmospheric pressure system played a prominent role for South American Summer Monsoon dynamics during glacial episodes.

AB - Recent developments in terrestrial cosmogenic nuclide (TCN) exposure dating and the reinterpretation of TCN boulder ages from moraines have improved our understanding of the glacial chronology in the Central Andes. According to these records, glacial advances throughout the region correlate with insolation-driven changes in the intensity of the South American Summer Monsoon and millennial-scale climate events such as Heinrich Stadials and the Younger Dryas. Quantifying the temperature and precipitation shifts during these events helps to constrain past moisture pathways and associated changes in atmospheric circulation patterns. Yet, particularly in the southern Central Andes, where a wealth of glacigenic landforms attests to formerly cooler and/or wetter conditions, the magnitudes of past temperature and precipitation changes are only loosely constrained at a few sites. Here, we present results from TCN-dated moraines combined with the reconstruction of former glaciers and paleolakes within the eastern sector of the southern Central Andes (24°–27°S) for the Last Glacial Maximum (LGM), Heinrich Stadial 1 (HS1), and the Younger Dryas (YD). We performed Monte-Carlo simulations with 2-dimensional models of ice flow and lake hydrology that are forced by a spatially-distributed surface energy balance model. Our results indicate that temperatures were 3.0–4.2 °C, 2.0–3.3 °C and 1.3–2.5 °C cooler during the LGM, HS1 and YD, respectively, in agreement with previous estimates elsewhere in the Central Andes. We find that temperature changes during the late glacial are compatible with sea-surface temperature anomalies derived from the tropical Atlantic. Precipitation was only 5–27% greater than today, which contrasts with larger anomalies reconstructed for the Bolivian part of the Andean Plateau (Altiplano). We attribute this discrepancy to the southerly position of our study region with respect to the Bolivian High, supporting the hypothesis that this atmospheric pressure system played a prominent role for South American Summer Monsoon dynamics during glacial episodes.

KW - Bolivian high

KW - Central andes

KW - Exposure age dating

KW - Glaciation

KW - Heinrich stadial 1

KW - Landslidedammed lake

KW - Last glacial maximum

KW - Monsoon

KW - Moraines

KW - Paleoclimatology

KW - South America

KW - Younger dryas

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U2 - 10.1016/j.quascirev.2020.106592

DO - 10.1016/j.quascirev.2020.106592

M3 - Journal article

AN - SCOPUS:85091571986

SN - 0277-3791

VL - 248

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

M1 - 106592

ER -

Temperature and precipitation in the southern Central Andes during the last glacial maximum, Heinrich Stadial 1, and the Younger Dryas

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