| 1. |
- Dalton, April S., et al.
(author)
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Last Interglacial (MIS 5e) sea level proxies in the glaciated Northern Hemisphere
- 2021
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Other publication (other academic/artistic)abstract
- Because global sea level during the last interglacial (LIG; 130–115 ka) was higher than today, the LIG is a useful analogue for improving predictions of future sea level rise. Here, we synthesize sea level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) database. We describe 82 sites from Russia, northern Europe, Greenland and North America from a variety of settings, including boreholes, riverbank exposures and along coastal cliffs. Marine sediments at these sites were constrained to the LIG using a variety of radiometric methods (radiocarbon, U-Series dating, K-Ar dating), non-radiometric methods (amino acid dating, luminescence methods, and electron spin resonance, tephrochronology) as well as various stratigraphic and palaeoenvironmental approaches. As the areas in this database were covered by ice sheets from the penultimate glaciation and were affected by glacial isostatic adjustment (GIA), most of the proxies show that sea level was much higher than present during the LIG. Many of the sites show evidence of regression due sea level fall due to GIA uplift, and some also show fluctuations that may reflect regrowth of continental ice or increased influence of the global sea level signal. The database is available at https://doi.org/10.5281/zenodo.5602212 (Dalton et al., 2021).
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| 2. |
- Dalton, April S., et al.
(author)
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Last interglacial (MIS 5e) sea level proxies in the glaciated Northern Hemisphere
- 2022. - 4
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Other publication (other academic/artistic)abstract
- Because global sea level during the last interglacial (LIG; 130–115 ka) was higher than today, the LIG is a useful analogue for improving predictions of future sea level rise. Here, we synthesize sea level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) database. We describe 82 sites from Russia, northern Europe, Greenland and North America from a variety of settings, including boreholes, riverbank exposures and along coastal cliffs. Marine sediments at these sites were constrained to the LIG using a variety of radiometric methods (radiocarbon, U-Series dating, K-Ar dating), non-radiometric methods (amino acid dating, luminescence methods, and electron spin resonance, tephrochronology) as well as various stratigraphic and palaeoenvironmental approaches. As the areas in this database were covered by ice sheets from the penultimate glaciation and were affected by glacial isostatic adjustment (GIA), most of the proxies show that sea level was much higher than present during the LIG. Many of the sites show evidence of regression due sea level fall due to GIA uplift, and some also show fluctuations that may reflect regrowth of continental ice or increased influence of the global sea level signal. The database is available at https://doi.org/10.5281/zenodo.5602212 (Dalton et al., 2021).
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| 3. |
- Dalton, April S, et al.
(author)
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Last interglacial sea-level proxies in the glaciated Northern Hemisphere
- 2022
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In: Earth System Science Data. - : Copernicus GmbH. - 1866-3516. ; 14:4, s. 1447-1492
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Journal article (peer-reviewed)abstract
- Because global sea level during the last interglacial (LIG; 130–115 ka) was higher than today, the LIG is a useful approximate analogue for improving predictions of future sea-level rise. Here, we synthesize sea-level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) database. We describe 82 sites from Russia, northern Europe, Greenland and North America from a variety of settings, including boreholes, riverbank exposures and along coastal cliffs. Marine sediments at these sites were constrained to the LIG using a variety of radiometric methods (radiocarbon, uranium–thorium, potassium–argon), non-radiometric methods (amino acid dating, luminescence methods, electron spin resonance, tephrochronology) as well as various stratigraphic and palaeo-environmental approaches. In general, the sites reported in this paper do not offer constraint on the global LIG highstand, but rather evidence of glacial isostatic adjustment (GIA)-influenced sea-level positions following the Marine Isotope Stage 6 glaciation (MIS 6; 191–130 ka). Most of the proxies suggest that sea level was much higher during the LIG than at the present time. Moreover, many of the sites show evidence of regression due to sea-level fall (owing to glacial isostatic uplift), and some also show fluctuations that may reflect regrowth of continental ice or increased influence of the global sea-level signal. In addition to documenting LIG sea-level sites in a large swath of the Northern Hemisphere, this compilation is highly relevant for reconstructing the size of MIS 6 ice sheets through GIA modelling. The database is available at https://doi.org/10.5281/zenodo.5602212 (Dalton et al., 2021).
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| 4. |
- Gowan, Evan J., et al.
(author)
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A new global ice sheet reconstruction for the past 80000 years
- 2021
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Journal article (peer-reviewed)abstract
- The evolution of past global ice sheets is highly uncertain. One example is the missing ice problem during the Last Glacial Maximum (LGM, 26000-19000 years before present) - an apparent 8-28 m discrepancy between far-field sea level indicators and modelled sea level from ice sheet reconstructions. In the absence of ice sheet reconstructions, researchers often use marine delta O-18 proxy records to infer ice volume prior to the LGM. We present a global ice sheet reconstruction for the past 80000 years, called PaleoMIST 1.0, constructed independently of far-field sea level and delta O-18 proxy records. Our reconstruction is compatible with LGM far-field sea-level records without requiring extra ice volume, thus solving the missing ice problem. However, for Marine Isotope Stage 3 (57000-29000 years before present) - a pre-LGM period - our reconstruction does not match proxy-based sea level reconstructions, indicating the relationship between marine delta O-18 and sea level may be more complex than assumed. The configuration of past ice sheets, and therefore sea level, is highly uncertain. Here, the authors provide a global reconstruction of ice sheets for the past 80,000 years that allows to test proxy based sea level reconstructions and helps to reconcile disagreements with sea level changes inferred from models.
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| 5. |
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| 6. |
- Jan, Mangerud, et al.
(author)
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The Fennoscandian Ice Sheet during the Younger Dryas Stadial
- 2022
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In: European Glacial Landscapes: The Last Deglaciation. - 9780323918992 ; , s. 437-452
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Book chapter (other academic/artistic)abstract
- The Younger Dryas (YD) moraines have been mapped almost continuously around the Fennoscandian ice sheet. Segments of the moraine have individual names, best known are the Salpausselkä in Finland, the Middle Swedish moraines in Sweden and the Ra and the Herdla-Halsnøy moraines in Norway. The outline of the ice margin was very different around the ice sheet, with narrow fjord glaciers in western Norway and smoother margins and wide lobes in the lowlands of Sweden and Finland. The form and composition of the ice-marginal deposits also vary from narrow till ridges to large deltas and sandurs. Along many stretches there are two or more parallel ice-marginal deposits, notably in Finland and Sweden, whereas there is often only one ridge in western Norway. Most of the moraines are confidently dated to the YD, but with some variation in precise timing; the Herdla-Halsnøy moraines were formed at the very end of the YD, the outermost Salpausselkä and Middle Swedish moraines were formed earlier during the YD. In a few places it is unclear if all parallel ridges are of YD age.
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| 7. |
- Wang, Yucheng, et al.
(author)
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Late Quaternary Dynamics of Arctic Biota from Ancient Environmental Genomics
- 2021
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 600:7887, s. 86-92
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Journal article (peer-reviewed)abstract
- During the last glacial–interglacial cycle, Arctic biotas experienced substantial climatic changes, yet the nature, extent and rate of their responses are not fully understood1–8. Here we report a large-scale environmental DNA metagenomic study of ancient plant and mammal communities, analysing 535 permafrost and lake sediment samples from across the Arctic spanning the past 50,000 years. Furthermore, we present 1,541 contemporary plant genome assemblies that were generated as reference sequences. Our study provides several insights into the long-term dynamics of the Arctic biota at the circumpolar and regional scales. Our key fndings include: (1) a relatively homogeneous steppe–tundra fora dominated the Arctic during the Last Glacial Maximum, followed by regional divergence of vegetation during the Holocene epoch; (2) certain grazing animals consistently co-occurred in space and time; (3) humans appear to have been a minor factor in driving animal distributions; (4) higher efective precipitation, as well as an increase in the proportion of wetland plants, show negative efects on animal diversity; (5) the persistence of the steppe–tundra vegetation in northern Siberia enabled the late survival of several now-extinct megafauna species, including the woolly mammoth until 3.9 ± 0.2 thousand years ago (ka) and the woolly rhinoceros until 9.8 ± 0.2 ka; and (6) phylogenetic analysis of mammoth environmental DNA reveals a previously unsampled mitochondrial lineage. Our fndings highlight the power of ancient environmental metagenomics analyses to advance understanding of population histories and long-term ecological dynamics
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| 8. |
- Wang, Yucheng, et al.
(author)
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Reply to: When did mammoths go extinct?
- 2022
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 612:7938, s. 4-6
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Journal article (peer-reviewed)
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