A multi-proxy lithostratigraphic record of Late Glacial and Holocene climate variability from Piper Lake, Nova Scotia

2005 ◽  
Vol 42 (11) ◽  
pp. 2039-2049 ◽  
Author(s):  
Ian S Spooner ◽  
Ian MacDonald ◽  
Brandon Beierle ◽  
AJ Timothy Jull
Keyword(s):  
Nova Scotia ◽  
Environmental Variability ◽  
Regional Climate ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Late Glacial ◽  
Low Carbon ◽  
The Holocene ◽  
Late Glacial And Holocene ◽  
The Impact

A multi-proxy lithostratigraphic record from Piper Lake, Nova Scotia reveals environmental variability during the Late Glacial and Holocene. Piper Lake is a small, shallow (3 m), closed dystrophic basin located in the eastern Nova Scotia Highlands. The site was deglaciated about 14.5 cal (calibrated) ka BP and elevated loss on ignition values and relatively low carbon/nitrogen (C/N) isotope ratios indicate the establishment of a productive aquatic environment consistent with Allerød warming. The Late Glacial Lake record is punctuated by two thin, very fine-grained clay layers that are correlative to the Killarney and Younger Dryas (YD) oscillations; they were deposited when perennial ice covered the lake. The post-YD lithostratigraphy indicates the rapid establishment of an increasingly productive and stable landscape. This trend is reversed three times during the Holocene by minerogenic units. A complex 25 cm thick diamicton unique to Piper Lake was deposited ca. 10.8–10.3 cal ka BP by slumping that was associated with periglacial slope processes and (or) lake level changes; a direct correlation to early Holocene (Preboreal) cooling appears unlikely. Two thin minerogenic units deposited at ca. 8.1 and ca. 4.9 cal ka BP were likely the result of regional cooling and are broadly correlative with events noted in the GISP2 (Greenland Ice Sheet Project 2) ice-core record. The Holocene lithostratigraphic record from Piper Lake may be a consequence of unique limnological factors. Alternatively, the strong lithostratigraphic response may be the result of the absence of a strong and persistent regional climate mechanism (North Atlantic oscillation?), which if present might have obscured the impact of hemispheric or larger-scale climate forcing.

Late Holocene thermohaline perturbation of the N-Atlantic Subpolar Gyre linked to exceptional Greenland Ice Sheet melting between 4.4 and 4.0 ka BP

2020 ◽  
Author(s):  
Antoon Kuijpers ◽  
Marit-Solveig Seidenkrantz ◽  
Ralph Schneider ◽  
Camilla S. Andresen ◽  
Signe Hygom Jacobsen ◽  
...  
Keyword(s):  
Late Holocene ◽  
Deep Convection ◽  
Water Discharge ◽  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Subpolar Gyre ◽  
The Holocene ◽  
Master Thesis ◽  
The Impact

<p>Knowledge of the impact of past climate warming on Greenland Ice Sheet stability is an important issue for assessing  thresholds that are critical for a potential ice sheet collapse. For the late Holocene, evidence has recently been found of a so-called 4.2 ka BP event(1) including a prominent warming spike in several ice core records from Greenland and Canada (Agassiz).  Also lake records from both Northwest(2) and South Greenland(3) support pronounced summer warming during that time. After c. 4.0 ka BP NW Greenland July air temperature dropped by about 3<sup>o</sup> C. Coeval with this exceptional atmospheric warming anomaly over northern Canada and parts of Greenland, abrupt cooling and freshening affected  the N-Atlantic subpolar gyre where Labrador Sea deep convection ceased(4). Northern N-Atlantic climate generally deteriorated. With our contribution we present Holocene sub-bottom profiling  and sedimentary shelf and  fjord records from Southwest Greenland and Disko Bay that indicate exceptional Greenland Ice Sheet melting 4.4-4.0 ka BP at a rate and magnitude not recorded since early Holocene deglaciation. Extremely strong melt water discharge resulted in erosion of fjord sediments(5) and local deposition of up to several meters thick meltwater sediment on the shelf(6-8).  Timing of this melting event corresponds to a significant anomaly in hydrographic parameters of the Labrador Current off Newfoundland(9,10), which is concluded to have resulted in thermohaline perturbation of the N-Atlantic Subpolar gyre.   </p><ul><li>(1) Weiss, H. 2019. Clim Past doi:10.5194/cp-2018-162-RC2</li> <li>(2) McFarlin, J.M. et al. 2018. PNAS doi:10.1073/pnas.1720420115</li> <li>(3) Andresen, C.S. et al. 2004. J Quat Sci 19(8) doi:10.1002/jqs.886</li> <li>(4) Klus, A. et al. 2018. Clim Past doi:10.5194/cp-14-1165-2018</li> <li>(5) Ren, J. et al. 2009. Mar Micropal doi:10.1016/j.marmicro.2008.12.003</li> <li>(6) Hygom Jacobsen, S. 2019. Master Thesis Aarhus Univ, Dept. of Geoscience, pp105</li> <li>(7) Schneider, R. 2015. Cruise Rep epic.awi.de/id/eprint/37062/131/msm-44-46-expeditionsheft.pdf</li> <li>(8) Kuijpers, A. et al. 2001. Geol. Greenland Surv Bull 189, 41-47</li> <li>(9) Solignac, S. et al. 2011. The Holocene, doi: 10.1177/0959683610385720</li> <li>(10) Orme, L. et al 2019. The Holocene (submitted)</li> </ul>

Modelled Holocene thinning in Greenland improved by new developed transient past climatologies.

2021 ◽  
Author(s):  
Ilaria Tabone ◽  
Alexander Robinson ◽  
Jorge Alvarez-Solas ◽  
Javier Blasco ◽  
Daniel Moreno ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Model Parameters ◽  
Last Deglaciation ◽  
The Holocene ◽  
Model Mismatch ◽  
Elevation Changes ◽  
The Impact

<p>Reconstructions of Greenland Summit elevation changes indicate at least 150 m of surface thinning since the onset of the Holocene. Even higher thinning values are found at locations closer to the ice-sheet margin, where the influence of higher ablation rates and ocean-induced retreat is greater. Interestingly, the performance of 3D ice-sheet models in representing such elevation changes is generally poor, even though they can reasonably reproduce the state of the ice sheet at different times, such as the last glacial maximum (LGM) or the present day. The reasons behind this data-model mismatch are still unclear. Here we use a recently developed 3D ice-sheet-shelf model to test the impact of different model parameters and of boundary conditions on simulating the Greenland ice sheet evolution through the last deglaciation to today. Specifically, we investigate the role of past climatologies in reproducing the elevation changes at ice core sites when used to force the ice-sheet model. By applying recently developed transient deglacial climatologies we can investigate the ice-sheet deglaciation with exceptional detail. Results support the need of additional transient climatologies to be released to ensure a robust description of the Greenland retreat history throughout the Holocene. </p>

Do Greenland Ice Cores Reflect NW European Interglacial Climate Variations?

1995 ◽  
Vol 43 (2) ◽  
pp. 125-132 ◽  
Author(s):  
Eiliv Larsen ◽  
Hans Petter Sejrup ◽  
Sigfus J. Johnsen ◽  
Karen Luise Knudsen
Keyword(s):  
Western Europe ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
High Amplitude ◽  
Atlantic Water ◽  
Polar Front ◽  
Norwegian Sea ◽  
The Holocene ◽  
Climatic Evolution

AbstractThe climatic evolution during the Eemian and the Holocene in western Europe is compared with the sea-surface conditions in the Norwegian Sea and with the oxygen-isotope-derived paleotemperature signal in the GRIP and Renland ice cores from Greenland. The records show a warm phase (ca. 3000 yr long) early in the Eemian (substage 5e). This suggests that the Greenland ice sheet, in general, recorded the climate in the region during this time. Rapid fluctuations during late stage 6 and late substage 5e in the GRIP ice core apparently are not recorded in the climatic proxies from western Europe and the Norwegian Sea. This may be due to low resolution in the terrestrial and marine records and/or long response time of the biotic changes. The early Holocene climatic optimum recorded in the terrestrial and marine records in the Norwegian Sea-NW European region is not found in the Summit (GRIP and GISP2) ice cores. However, this warm phase is recorded in the Renland ice core. Due to the proximity of Renland to the Norwegian Sea, this area is probably more influenced by changes in polar front positions which may partly explain this discrepancy. A reduction in the elevation at Summit during the Holocene may, however, be just as important. The high-amplitude shifts during substage 5e in the GRIP core could be due to Atlantic water oscillating closer to, and also reaching, the coast of East Greenland. During the Holocene, Atlantic water was generally located farther east in the Norwegian Sea than during the Eemian.

Late Glacial and Holocene environmental variability, Lago Trasimeno, Italy

2021 ◽  
Author(s):  
Luca Gasperini ◽  
Dorothy Peteet ◽  
Enrico Bonatti ◽  
Ermanno Gambini ◽  
Alina Polonia ◽  
...  
Keyword(s):  
Environmental Variability ◽  
Late Glacial ◽  
Late Glacial And Holocene

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

2013 ◽  
Vol 9 (4) ◽  
pp. 1629-1643 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene thermal maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveals a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from the previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in an ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of the early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

scholarly journals Impact of updated radiative transfer scheme in RACMO2.3p3 on the surface mass and energy budget of the Greenland ice sheet

2020 ◽  
Author(s):  
Christiaan T. van Dalum ◽  
Willem Jan van de Berg ◽  
Michiel R. van den Broeke
Keyword(s):  
Radiative Transfer ◽  
Energy Budget ◽  
Climate Model ◽  
Regional Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Melt ◽  
Transfer Scheme ◽  
Surface Mass ◽  
The Impact

Abstract. This study evaluates the impact of a new snow and ice albedo and radiative transfer scheme on the surface mass and energy budget for the Greenland ice sheet in the latest version of the regional climate model RACMO2, version 2.3p3. We also evaluate the modeled (sub)surface temperature and snow melt, as subsurface heating by radiation penetration now occurs. The results are compared to the previous model version and are evaluated against stake measurements and automatic weather station data of the K-transect and PROMICE projects. In addition, subsurface snow temperature profiles are compared at the K-transect, Summit and southeast Greenland. The surface mass balance is in good agreement with observations, and only changes considerably with respect to the previous RACMO2 version around the ice margins and in the percolation zone. Snow melt and refreezing, on the other hand, are changed more substantially in various regions due to the changed albedo representation, subsurface energy absorption and melt water percolation. Internal heating leads to considerably higher snow temperatures in summer, in agreement with observations, and introduces a shallow layer of subsurface melt.

Climatic, Solar, Oceanic, and Geomagnetic Influences on Late-Glacial and Holocene Atmospheric 14C/12C Change

1991 ◽  
Vol 35 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Minze Stuiver ◽  
Thomas F. Braziunas ◽  
Bernd Becker ◽  
Bernd Kromer
Keyword(s):  
Ocean Circulation ◽  
Time Scale ◽  
Late Glacial ◽  
Minor Role ◽  
Activity Levels ◽  
Data Set ◽  
The Holocene ◽  
Spectral Interpretation ◽  
Late Glacial And Holocene ◽  
A Minor

AbstractLate-glacial and Holocene 14C/12C ratios of atmospheric CO2 vary in magnitude from a few per mil for annual/decadal pertubations to more than 10% for events lasting millennia. A data set illuminating 10- to 104-yr variability refines our understanding of oceanic (climatic) versus geomagnetic or solar forcing of atmospheric 14C/12C ratios. Most of the variance in the Holocene atmospheric 14C/12C record can be attributed to the geomagnetic (millennia time scale) and solar (century time scale) influence on the flux of primary cosmic rays entering the atmosphere. Attributing the observed atmospheric 14C/12C changes to climate alone leads to ocean circulation and/or global wind speed changes incompatible with proxy records. Climate-(ocean-)related 14C redistribution between carbon reservoirs, while evidently playing a minor role during the Holocene, may have perturbed atmospheric 14C/12C ratios measurably during the late-glacial Younger Dryas event. First-order corrections to the radiocarbon time scale (12,000–30,000 14C yr B.P.) are calculated from adjusted lake-sediment and tree-ring records and from geomagnetically defined model 14C histories. Paleosunspot numbers (100–9700 cal yr B.P.) are derived from the relationship of model 14C production rates to sunspot observations. The spectral interpretation of the 14C/12C atmospheric record favors higher than average solar activity levels for the next century. Minimal evidence was found for a sun-weather relationship.

scholarly journals The effect of precipitation seasonality on Eemian ice core isotope records from Greenland

2013 ◽  
Vol 9 (1) ◽  
pp. 269-296 ◽  
Author(s):  
W. J. van de Berg ◽  
M. R. van den Broeke ◽  
E. van Meijgaard ◽  
F. Kaspar
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Ice Core ◽  
Greenland Ice Sheet ◽  
Ice Cores ◽  
Condensation Temperature ◽  
Temperature Changes ◽  
Mean Temperature ◽  
Precipitation Seasonality ◽  
Climate Proxies

Abstract. The previous interglacial (Eemian, 130–114 kyr BP) had a mean sea level highstand 4 to 7 m above the current level, and, according to climate proxies, a 2 to 6 K warmer Arctic summer climate. Greenland ice cores extending back into the Eemian show a reduced depletion in δ18O of about 3‰ for this period, which suggests a significant warming of several degrees over the Greenland ice sheet. Since the depletion in δ18O depends, among other factors, on the condensation temperature of the precipitation, we analyze climatological processes other than mean temperature changes that influence condensation temperature, using output of the regional climate model RACMO2. This model is driven by ERA-40 reanalysis and ECHO-G GCM boundaries for present-day, preindustrial and Eemian climate. The processes that affect the condensation temperature of the precipitation are analyzed using 6-hourly model output. Our results show that changes in precipitation seasonality can cause significant changes of up to 2 K in the condensation temperature that are unrelated to changes in mean temperature.

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere-sea ice-ocean model

2012 ◽  
Vol 8 (5) ◽  
pp. 5263-5291 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene Thermal Maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveal a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from a previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in a ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that the modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

scholarly journals High-frequency climate variability in the Holocene from a coastal-dome ice core in east-central Greenland

2020 ◽  
Vol 16 (4) ◽  
pp. 1369-1386
Author(s):  
Abigail G. Hughes ◽  
Tyler R. Jones ◽  
Bo M. Vinther ◽  
Vasileios Gkinis ◽  
C. Max Stevens ◽  
...  
Keyword(s):  
Sea Ice ◽  
Regional Climate ◽  
Ice Core ◽  
Sea Surface ◽  
Climate Information ◽  
East Central ◽  
Surface Conditions ◽  
The Holocene ◽  
Isotope Record ◽  
Water Isotope

Abstract. An ice core drilled on the Renland ice cap in east-central Greenland contains a continuous climate record dating through the last glacial period. The Renland record is valuable because the coastal environment is more likely to reflect regional sea surface conditions compared to inland Greenland ice cores that capture synoptic variability. Here we present the δ18O water isotope record for the Holocene, in which decadal-scale climate information is retained for the last 8 kyr, while the annual water isotope signal is preserved throughout the last 2.6 kyr. To investigate regional climate information preserved in the water isotope record, we apply spectral analysis techniques to a 300-year moving window to determine the mean strength of varying frequency bands through time. We find that the strength of 15–20-year δ18O variability exhibits a millennial-scale signal in line with the well-known Bond events. Comparison to other North Atlantic proxy records suggests that the 15–20-year variability may reflect fluctuating sea surface conditions throughout the Holocene, driven by changes in the strength of the Atlantic Meridional Overturning Circulation. Additional analysis of the seasonal signal over the last 2.6 kyr reveals that the winter δ18O signal has experienced a decreasing trend, while the summer signal has predominantly remained stable. The winter trend may correspond to an increase in Arctic sea ice cover, which is driven by a decrease in total annual insolation, and is also likely influenced by regional climate variables such as atmospheric and oceanic circulation. In the context of anthropogenic climate change, the winter trend may have important implications for feedback processes as sea ice retreats in the Arctic.

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