Evolution of the Laurentide and Innuitian ice sheets prior to the Last Glacial Maximum (115 ka to 25 ka)

Dalton, Andrew; Stokes, Chris R.; Batchelor, Christine

doi:10.1016/j.earscirev.2021.103875

Cited by 62 publications

(75 citation statements)

References 181 publications

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“…Using the climate matrix method, only the Laurentide and Cordilleran ice domes develop, which merge around 40 ka. In the glacial index method, This North American ice sheet with few inception regions in the climate matrix method agrees better with studies conducted with geological constraints (e.g., Batchelor et al, 2019, Dalton et al, 2022.…”

Section: Ice Sheet -Climate Feedbackssupporting

confidence: 72%

“…Little evidence exists on the inception phase of the LGC, since later glaciations tend to have removed most geological evidence. Modelling studies based on geological evidence, such as e.g., Bahadory et al (2021) and Dalton et al (2022), suggest that the North American ice sheet incepted at Ellesmere Island and the Canadian Cordillera, which agrees reasonably well for each simulation except for COSMOS forcing.…”

Section: Climate Forcingsupporting

confidence: 55%

“…However, neither the glacial index nor climate matrix method match global eustatic sea level evolution well during the LGM when comparing it to reconstructions (e.g., Gowan et al, 2021). In both the glacial index and climate matrix methods ice volume generally increases gradually, while studies that depend more on geological constrains such as Batchelor et al, 2019 andDalton et al, 2022 suggest a more dynamic change in ice volume and area for the North American ice sheet. Our method is unable to capture the sea level rise during MIS-3, when most of the Eurasian ice sheet is lost.…”

Section: Discussionmentioning

confidence: 99%

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Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Scherrenberg

Berends

Stap

et al. 2022

Preprint

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During the Last Glacial Cycle (LGC), ice sheets covered large parts of Eurasia and North America which resulted in ~120 meters of sea level change. Ice sheet -climate interactions have considerable influence on temperature and precipitation patterns, and therefore need to be included when simulating this time period. Ideally, ice sheet -climate interactions are simulated by a high-resolution earth system model. While these models are capable of simulating climates at a certain point in time, such as the Pre-Industrial (PI) or the Last Glacial Maximum (LGM; 21,000 years ago), a full glacial cycle is currently unfeasible as it requires a too large amount of computation time. Nevertheless, ice-sheet models require forcing that captures the gradual change in climate over time to calculate the accumulation and melt of ice and its effect on ice sheet extent and volume changes.Here we simulate the LGC using an ice sheet model forced by LGM and PI climates. The gradual change in climate is modelled by transiently interpolating between pre-calculated results from a climate model for the LGM and the PI. To assess the influence of ice sheet -climate interactions, we use two different interpolation methods: The climate matrix method, which includes these interactions, and the glacial index method, which does not. To investigate the sensitivity of the results to the prescribed climate forcing, we use the output of several models that are part of the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3). In these simulations, ice volume is prescribed and the climate is reconstructed. Here we test those models by using their climate to drive an ice sheet model over the LGC.We find that the differences caused by the climate forcing exceeds the differences caused by the interpolation method. Some General Circulation Models (GCMs) produced unrealistic LGM volumes and only four resulted in reasonable ice sheets with LGM Northern Hemisphere sea level contribution ranging between 74 -113 meters with respect to the present day. The glacial index and climate matrix methods result in similar ice volumes at LGM but yield a different ice evolution with different ice domes during the inception phase of the glacial cycle, and different sea-level rates during the deglaciation phase. The temperature-albedo feedback is the main cause of differences between the glacial index and climate matrix methods.

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Section: Ice Sheet -Climate Feedbackssupporting

confidence: 72%

Section: Climate Forcingsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

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Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Scherrenberg

Berends

Stap

et al. 2022

Preprint

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“…One of the notable sediment events that captured the imagination of marine geoscientists and paleo-climatologists over the last three decades is the H events and their direct relationship to the dynamics of ice sheets surrounding the North Atlantic during the last glacial cycle (Bond et al, 1993;Hillaire-Marcel et al, 1994;Dalton et al, 2022;and references therein). The rich literature on H events (Cf.…”

Section: Introductionmentioning

confidence: 99%

“…The rich literature on H events (Cf. Dalton et al, 2022;Andrews and Voelker, 2018; and references therein) state that Heinrich (1988) provided the first account of six iceberg rafting events (H events) during the last glaciation from the Dreizac seamounts of the NE Atlantic. Subsequently, Bond et al (1993) correlated H events to broad atmospheric and sea surface temperature changes in the North Atlantic and the surrounding regions and connected H events to global climate changes.…”

Section: Introductionmentioning

confidence: 99%

Contrasting Along-Slope vs. Downslope Sedimentation Style on the High-Latitude Eastern Canadian Continental Margin During the Last 40 ka

Rashid

Patro

et al. 2022

Front. Earth Sci.

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Late Pleistocene Labrador Sea depositional systems developed in front of ice streams and glacier outlets from the Laurentide Ice Sheet (LIS) are documented by Huntec and 3.5 kHz seismic profiles and piston cores. Due to efficient grinding by the LIS, massive amounts of fine-grained sediments and meltwater in addition to the icebergs linked to the Heinrich events (H events) of the last glaciation were delivered to the neighboring Labrador Sea. The position of the Hudson Strait ice stream during the periodic expansion and contraction on the Labrador margin allowed fine-grained sediments and meltwater direct delivery on the lower shelf and upper slope. These discharges were then transported southward by the Labrador Current and western boundary current. In contrast to the lower shelf and upper slope, sediments delivered on the mid to the lower Labrador Slope were transported by the Northwest Atlantic Mid-Ocean Channel to distal sites. The nepheloid flow layer at or near the sea bottom or at mid-water depths developed from meltwater loaded with an excessive charge of fine-grained sediments. Contrastingly, the non-discriminatory ice rafting process delivered detritus of all sizes, but its total contribution to the sediment column was only minor, notwithstanding its paleoclimatic significance during H events. Heinrich H1, H2, and H4 layers were identified by their characteristic nepheloid flow layer deposits, that is, alternating coarse silt and clay-sized laminae with thin ice-rafted debris interspersed by coarse- to fine-grained dropstone. Furthermore, the progressive thinning and eventual disappearance of the fine-laminae (i.e., coarse and fine silt/clay) in H layers at the distal sites suggest the exhaustion and raining out of fines due to long-distance transport. However, the H3 layer was identified by a combination of nepheloid flow layer deposits (upper slope) and finely laminated mud turbidites (lower slope and deep basin) at proximal sites. In the lower Labrador Slope and Basin, the H3 stratigraphic equivalent layer was identified by exorbitantly thick finely laminated carbonate-rich mud turbidites. The divergent sedimentation style (i.e., reflected by the sediment facies) and the thickness of the H3 layer compared to other H events suggest that the Hudson Strait ice stream position was different from other H events. Therefore, our data imply that the divergence in the H3 layer between the eastern and western North Atlantic might lie with the position of the Hudson Strait ice stream on the Labrador continental margin.

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Neutral markers reveal complex population structure across the range of a widespread songbird

Veale,

Reudink,

Burg

2024

Ecology and Evolution

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Understanding how both contemporary and historical physical barriers influence gene flow is key to reconstructing evolutionary histories and can allow us to predict species' resilience to changing environmental conditions. During the last glacial maximum (LGM), many high latitude North American bird species were forced into glacial refugia, including mountain bluebirds (Silia currucoides). Within their current breeding range, mountain bluebirds still experience a wide variety of environmental conditions and barriers that may disrupt gene flow and isolate populations. Using single nucleotide polymorphisms (SNPs) obtained through restriction site‐associated DNA sequencing, we detected at least four genetically distinct mountain bluebird populations. Based on this structure, we determined that isolation‐by‐distance, the northern Rocky Mountains, and discontinuous habitat are responsible for the low connectivity and the overall history of each population going back to the last glacial maximum. Finally, we identified five candidate genes under balancing selection and three loci under diversifying selection. This study provides the first look at connectivity and gene flow across the range of these high‐altitude and high latitude songbirds.

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Evolution of the Laurentide and Innuitian ice sheets prior to the Last Glacial Maximum (115 ka to 25 ka)

Cited by 62 publications

References 181 publications

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Interactions between the Northern-Hemisphere ice sheets and climate during the Last Glacial Cycle

Contrasting Along-Slope vs. Downslope Sedimentation Style on the High-Latitude Eastern Canadian Continental Margin During the Last 40 ka

Neutral markers reveal complex population structure across the range of a widespread songbird

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