Deglaciation of the Colorado Rocky Mountains following the Last Glacial Maximum

Leonard, Eric M.; Laabs, Benjamin J.C.; Schweinsberg, Avriel D.; Russell, C.; Briner, Jason P.; Young, Nicolás E.

doi:10.18172/cig.3234

Cited by 16 publications

(45 citation statements)

References 72 publications

(189 reference statements)

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“…Thus, we argue that the last glaciation in the Mosquito Range culminated at $20-21 ka during the latter part of the global LGM (26.5-19.0 ka; Clark et al, 2009). This timing is consistent with the conclusions of a recent review of available cosmogenic exposure ages in Colorado by Leonard et al (2017b) wherein they showed that individual valley glacier maxima generally occurred before $19.5 ka. Leonard et al (2017b) also concluded that retreat or abandonment of terminal moraines in Colorado was asynchronous, possibly well underway at $17-16 ka in the San Juan Mountains and Front Range, while glaciers remained at or near their maximum extents in the Sawatch Range and Sangre de Cristo Mountains at that time.…”

Section: Chronology Of Glacial Depositssupporting

confidence: 91%

“…This timing is consistent with the conclusions of a recent review of available cosmogenic exposure ages in Colorado by Leonard et al . () wherein they showed that individual valley glacier maxima generally occurred before ∼19.5 ka.…”

Section: Discussionmentioning

confidence: 97%

“…Leonard et al . () also concluded that retreat or abandonment of terminal moraines in Colorado was asynchronous, possibly well underway at ∼17–16 ka in the San Juan Mountains and Front Range, while glaciers remained at or near their maximum extents in the Sawatch Range and Sangre de Cristo Mountains at that time. The younger 10 Be ages on the recessional moraine in Union Canyon (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Several authors (e.g. Applegate et al, 2010;Heyman et al, 2011;Leonard et al, 2017b) have pointed out that the ages (mean, distribution, etc.) of moraine boulders can be interpreted differently.…”

Section: Chronology Of Glacial Depositsmentioning

confidence: 99%

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Late Pleistocene glaciation in the Mosquito Range, Colorado, USA: chronology and climate

Brugger

Laabs

Reimers

et al. 2019

J Quaternary Science

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New cosmogenic 10Be surface exposure ages from 17 moraine boulders in the Mosquito Range of Colorado suggest that glaciers were at their late Pleistocene (Pinedale) maximum extent at ∼21–20 ka, and that ice recession commenced before ∼17 ka. These age limits suggest that the Pinedale Glaciation was synchronous within the Colorado Rocky Mountain region. Locally, the previous (Bull Lake) glaciation appears to have occurred no later than 117 ka, possibly ∼130 ka allowing for reasonable rock weathering rates. Temperature‐index modeling is used to determine the magnitude of temperature depression required to maintain steady‐state mass balances of seven reconstructed glaciers at their maximum extent. Assuming no significant differences in precipitation compared to modern values, mean annual temperatures were ∼8.1 and 7.5 °C lower, respectively, on the eastern and western slopes of the range with quantifiable uncertainties of + 0.8/−0.9 °C. If an average temperature depression of 7.8 °C is assumed for the entire range, precipitation differences − that today are 15–30% greater on the eastern slope due to the influence of winter/early spring snowfall − might have been enhanced. The temperature depressions inferred here are consistent with similarly derived values elsewhere in the Colorado Rockies and those inferred from regional‐scale climate modeling.

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Section: Chronology Of Glacial Depositssupporting

confidence: 91%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Chronology Of Glacial Depositsmentioning

confidence: 99%

See 2 more Smart Citations

Late Pleistocene glaciation in the Mosquito Range, Colorado, USA: chronology and climate

Brugger

Laabs

Reimers

et al. 2019

J Quaternary Science

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“…Exposure ages on these moraines mark the earliest stillstands or readvances during retreat and range from 20.4 to 14.1 ka [9]. Glaciers in several valleys remained near their maximum extents well after abandoning the terminal moraines while at the same time in others, glaciers had retreated significantly [10].…”

Section: Introductionmentioning

confidence: 99%

Climate during the Last Glacial Maximum in the Northern Sawatch Range, Colorado, USA

et al. 2019

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Temperature-index modeling is used to determine the magnitude of temperature depression in the northern Sawatch Range required to maintain steady-state mass balances of six reconstructed glaciers at their extent during the local Last Glacial Maximum (LLGM), dated at ~21 ka. Assuming no significant differences in precipitation compared to modern values, mean annual temperatures in the region were on average 8.8 + 0.5/– 0.8 °C cooler than they are today. Allowing for modest (± 10 cm) increases or decreases in precipitation, required temperature depressions only differ by ±0.2 °C. Temperature depression in the northern Sawatch Range is consistent, although slightly greater, with those determined in other ranges in Colorado using similar approaches. The estimates presented here are, however, substantially less than those suggested by several downscaled simulations of global Last Glacial Maximum (LGM) climate, that might be due to the need for improved calibration of such downscaled simulations, or the models from which they are derived. Our estimates of LGM temperature depression are considerably greater than that previously determined in the study area and those in two other ranges in Colorado derived using different methodologies, the latter being most likely responsible for the discrepancies.

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Mapping paleo-lacustrine environments and long-term climate trends using groundwater chemistry

Mayo¹

2020

Hydrogeol J

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Deglaciation of the Colorado Rocky Mountains following the Last Glacial Maximum

Cited by 16 publications

References 72 publications

Late Pleistocene glaciation in the Mosquito Range, Colorado, USA: chronology and climate

Late Pleistocene glaciation in the Mosquito Range, Colorado, USA: chronology and climate

Climate during the Last Glacial Maximum in the Northern Sawatch Range, Colorado, USA

Mapping paleo-lacustrine environments and long-term climate trends using groundwater chemistry

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