scholarly journals Geochronological reconsiderations for the Eastern European key loess section at Stayky in Ukraine

2013 ◽  
Vol 9 (3) ◽  
pp. 2629-2659 ◽  
Author(s):  
A. Kadereit ◽  
G. A. Wagner
Keyword(s):  
Global Climate ◽  
Ice Core ◽  
Late Glacial ◽  
The Arctic ◽  
Eastern European ◽  
Climate History ◽  
The North ◽  
Event Stratigraphy ◽  
Age Model ◽  
Arctic Ice

Abstract. Event-stratigraphical correlations between local/regional terrestrial sedimentary archives and marine or ice-core records providing the global climate history and time-scale are highly desirable for a deeper understanding of the effects of global climate change on a local/regional (palaeo-)environment. However, such correlations are not trivial, as the terrestrial records tend to be floating and fragmentary and usually show varying sedimentation rates. Therefore, a reliable chronometric framework is a necessary prerequisite for any event-stratigraphy involving terrestrial archives. In this respect, the age-model underlying the event-stratigraphical approach for the Eastern European key loess section at Stayky in Ukraine appears to need revision. Here we explain, why it is highly unlikely that the Middle Pleniglacial Vytachiv Soil developed during Greenland interstadial (GIS) 8, and why the embryonic soils in the upper part of the Upper Pleniglacial part of the loess section most likely post-date Heinrich 2 event. As a consequence, the revised age-model challenges the earlier suggested correlation of the suite of incipient soils above the Vytachiv Soil with Greenland Interstadials, which was supposed to start with GIS7 but for which matching from after GIS5 seems more likely. The revised chronology suggests that the transition from Middle to Upper Pleniglacial environmental conditions at the Eastern European key section occurred during the final phase of marine isotope stage (MIS) 3. Thus, the picture appears to be in accordance with that of the Western European key section at Nussloch in Germany pointing to a common driver of palaeo-environmental change in both regions, such as early Late Glacial Maximum (LGM) advances of the Arctic ice-shield or changes of the North Atlantic circulation and sea-ice distribution leading also to relevant changes of the palaeowind field.

scholarly journals Geochronological reconsideration of the eastern European key loess section at Stayky in Ukraine

2014 ◽  
Vol 10 (2) ◽  
pp. 783-796 ◽  
Author(s):  
A. Kadereit ◽  
G. A. Wagner
Keyword(s):  
Global Climate ◽  
Ice Core ◽  
Soil Formation ◽  
Late Glacial ◽  
The Arctic ◽  
Eastern European ◽  
Climate History ◽  
The North ◽  
Event Stratigraphy ◽  
Age Model

Abstract. Event-stratigraphical correlations between regional terrestrial sedimentary archives and marine or ice-core records that provide climate history are highly desirable for a deeper understanding of the effects of global climate change. However, such correlations are not simple, as the terrestrial records tend to be floating and fragmentary, and usually show varying sedimentation rates. Therefore, a reliable chronometric framework is a prerequisite for any event stratigraphy involving terrestrial archives. We propose that the age model underlying the event-stratigraphical approach for the eastern European key loess section at Stayky in Ukraine needs revision. Here we explore why it is unlikely that the Middle Pleniglacial Vytachiv Soil developed during Greenland interstadial (GIS) 8, and why the embryonic soils in the upper part of the Upper Pleniglacial part of the loess section most likely post-date the Heinrich 2 event. As a consequence, the revised age-model challenges the earlier suggested correlation of the suite of incipient soils above the Vytachiv Soil with Greenland Interstadials, which was supposed to start with GIS7 but for which matching from after GIS5 seems more likely. The revised chronology suggests that the transition from Middle to Upper Pleniglacial environmental conditions at the eastern European key section occurred during the final phase of marine isotope stage (MIS) 3. Thus, the picture appears to be in accordance with that of the western European key section at Nussloch. This points to a common driver of palaeo-environmental change in both regions, such as early late glacial maximum (LGM) advances of the Arctic ice shield or changes of the North Atlantic circulation and sea-ice distribution associated with changes in the palaeowind field relevant to aeolian loess deposition and soil formation. To test and substantiate the alternative age model, more chronologies for well-stratified loess sections throughout the European loess belt are required.

Oriented lake-and-ridge assemblages of the Arctic coastal plains: glacial landforms modified by thermokarst and solifluction

Polar Record ◽  
1999 ◽  
Vol 35 (194) ◽  
pp. 215-230 ◽  
Author(s):  
Mikhail G. Grosswald ◽  
Terence J. Hughes ◽  
Norman P. Lasca
Keyword(s):  
Ice Sheet ◽  
Late Glacial ◽  
The Arctic ◽  
Laurentide Ice Sheet ◽  
Baffin Island ◽  
Mackenzie Delta ◽  
Space Images ◽  
The North ◽  
Arctic Ice ◽  
Glacial Landforms

AbstractOriented assemblages of parallel ridges and elongated lakes are widespread on the coastal lowlands of northeast Eurasia and Arctic North America, in particular, in Alaska, Arctic Canada, and northeast Siberia. So far, only the oriented lakes have been of much scientific interest. They are believed to be formed by thermokarst in perennially frozen ice-rich sediments, while their orientation is accounted for either by impact of modern winds blowing at right angles to long axes of the lakes (when it concerns individual lakes), or by the influence of underlying bedrock structures (in the case of longitudinal and transverse alignment of lake clusters).En masseexamination of space images suggests that oriented lake-and-ridge assemblages, not the oriented lakes alone, occur in the Arctic. Hence any theory about their formation should account for the origin and orientation of the assemblages as a whole. The existing hypotheses appear inadequate for this end, so this paper proposes that the assemblages were initially created by glacial activity, that is, by ice sheets that drumlinized and tectonized their beds, as well as by sub- and proglacial meltwater, and then they were modified by thermokarst, solifluction, and aeolian processes. This assumption opens up an avenue by which all known features of oriented landforms in the Arctic can be explained. The paper suggests that the oriented landforms in Siberia and Alaska are largely signatures of a marine Arctic ice sheet that transgressed from the north, while the Baffin Island and Mackenzie Delta forms were created by the respective sectors of the Laurentide ice sheet. The oriented features discussed belong to the last Late Glacial through the Early Holocene.

scholarly journals The Eemian interglacial in the North European plain and adjacent areas

2000 ◽  
Vol 79 (2-3) ◽  
pp. 217-231 ◽  
Author(s):  
Charles Turner
Keyword(s):  
Deep Sea ◽  
North Atlantic Ocean ◽  
Rapid Development ◽  
Ice Core ◽  
Late Glacial ◽  
Glacial Refugia ◽  
The Arctic ◽  
Massif Central ◽  
The Balkans ◽  
The North

AbstractMany small deposits of Eemian age, including the stratotype, are found right across the North European plain. In adjacent areas, this interglacial is known by local names such as Ipswichian (Britain), Luhe or Ribains (France), Riss-Würm interglacial (Alps) and Mikulinian (Poland and Russia). It correlates primarily with MIS 5e of the deep-sea stratigraphy, though boundaries may not be exactly the same. Basins containing Eemian sediments rest directly on morainic deposits of all three Saalian ice advances, which must all, therefore, fall within MIS 6.Indicator species of both plants and animals suggest that mean July temperatures in the early-temperate part of the interglacial were warmer than during the Holocene. For many years, palynologists have recognised a very uniform succession of temperate tree acme pollen zones and a substantial late-temperate expansion of Carpinus as hallmarks of this interglacial across much of northern Europe. In southern England, however, deposits with a similar pollen signature are being recognised on stratigraphie and palaeontological grounds as characterising not only the Ipswichian but also the previously poorly-defined interglacial stage correlating with MIS 7. High Carpinus values are known from these latter sites and from the Le Bouchet inter-glacial of the French Massif Central, also clearly correlated with MIS 7. Thus stratigraphie confusion and misinterpretations may have occurred at supposedly Eemian/Ipswichian sites unrelated to the glacial stratigraphy or to deep continuous records.The uniformity and rapid development of Eemian vegetational successions may be ascribed to (1) rapid warming and the lack of any late-glacial climatic oscillation on the scale of the Younger Dryas, (2) the development of an open marine connection in the first half of the interglacial from the English Channel across the North and Baltic Seas to the White Sea and the Arctic Ocean, and (3) the occurrence of Saalian per-glacial refugia for Carpinus, not only in the Balkans but also on the Iberian peninsula, permitting much more rapid northward colonisation of Europe during this interglacial.The question of climatic events within the Eemian is far from settled. Not only is the ice-core evidence ambiguous and awaiting further clarification, but the scale and synchroneity of proposed events at different continental sites in both northern and southern Europe show no clear pattern at present; clearly there is a need for more detailed investigation and interpretation. Likewise there is ongoing debate about the duration of this interglacial and its detailed correlation with the deep-sea core record and events within the North Atlantic Ocean.

Synchronization of late-glacial vegetation changes at Crystal Lake, Illinois, USA with the North Atlantic Event Stratigraphy

2009 ◽  
Vol 72 (2) ◽  
pp. 234-245 ◽  
Author(s):  
Leila M. Gonzales ◽  
Eric C. Grimm
Keyword(s):  
North Atlantic ◽  
Late Quaternary ◽  
Ice Core ◽  
Late Glacial ◽  
Vegetation Changes ◽  
Pollen Record ◽  
Climate Conditions ◽  
The North ◽  
Event Stratigraphy ◽  
The North Atlantic

AbstractLate-glacial (17–11 cal ka BP) pollen records from midwestern North America show similar vegetation trends; however, poor dating resolution, wide-interval pollen counts, and variable sedimentation rates have prevented the direct correlation with the North Atlantic Event Stratigraphy as represented in the Greenland ice-core records, thus preventing the understanding of the teleconnections and mechanisms of late-Quaternary events in the Northern Hemisphere. The widespread occurrence of late-glacial vegetation and climates with no modern analogs also hinders late-glacial climate reconstructions. A high-resolution pollen record with a well-controlled age model from Crystal Lake in northeastern Illinois reveals vegetation and climate conditions during the late-glacial and early Holocene intervals. Late-glacial Crystal Lake pollen assemblages, dominated by Picea mariana and Fraxinus nigra with lesser amounts of Abies and Larix, suggest relatively wet climate despite fluctuations between colder and warmer temperatures. Vegetation changes at Crystal Lake are coeval with millennial-scale trends in the NGRIP ice-core record, but major shifts in vegetation at Crystal Lake lag the NGRIP record by 300–400 yr. This lag may be due to the proximity of the Laurentide ice sheet, the ice sheet's inherent slowness in response to rapid climate changes, and its effect on frontal boundary conditions and lake-effect temperatures.

Palaeo-oceanography, margin stratigraphy and palaeophysiography of the Tertiary North Atlantic and Norwegian-Greenland seas

1980 ◽  
Vol 294 (1409) ◽  
pp. 177-185 ◽  
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Global Climate ◽  
Circulation Pattern ◽  
The Arctic ◽  
Continental Margins ◽  
Long Distance ◽  
Sea Level Fluctuations ◽  
The North ◽  
Border Zones

The Tertiary was a period of dramatic changes of the palaeo-oceanography of the world’s oceans in general and of the North Atlantic in particular. These changes were caused by (1) the bathymetric evolution of ocean basins and intrabasin pathways (opening of the Norwegian-Greenland Seas and of the pathway to the Arctic Ocean, interruption of the circumglobal equatorial seaway); (2) the geographical development of the oceans and adjacent marginal basins in the context of rapid and intensive eustatic sea level fluctuations; and (3) the deterioration of the global climate throughout the Tertiary (change from a non-glacial to a glacial world, causing major changes in circulation of the surface and deep water). A biostratigraphy of Tertiary sediments deposited close to the continental margins has been developed by using remains of planktonic floras and faunas. Their presence in these sediments and their usefulness for long distance correlations of margin sediments, depend upon the circulation pattern and hydrographic gradients of the oceanic surface and deep water masses, the climatic regime over the continental border zones, and the probability of their post-depositional preservation.

Challenges and opportunities extending the INTIMATE tephra event stratigraphy into the Levant and Arabia.

2020 ◽  
Author(s):  
Simon Blockley ◽  
Dustin White ◽  
Rhys Timms ◽  
Paul Lincoln ◽  
Simon Armitage ◽  
...  
Keyword(s):  
North Atlantic ◽  
Eastern Mediterranean ◽  
Ice Core ◽  
Limited Range ◽  
Geochemical Data ◽  
Interglacial Period ◽  
The North ◽  
Event Stratigraphy ◽  
The North Atlantic ◽  
The Mediterranean

<p>The nature and expression of climate change in the Eastern Mediterranean, the Levant and further into Arabia is of considerable interest across a range of communities. This is in part due to the need to understand the potential for future climate forcing on environments given the complex range of climatic forcing factors that play out in the region. These include the role of prevailing winds across the Mediterranean, Northerly winds pushing down into the region during cold glacial conditions, and the influence of the Afro-Arabian Monsoon. The last glacial to interglacial period is a critical window to examine such processes, as a range of climatic signals are recorded, many of which have been proposed as correlatives of events seen in the North Atlantic. Dating issues are as ever an issue when trying to precisely compare different climate archives. To address such, the INTIMATE event stratigraphy has been developed for the North Atlantic region, with recent extensions into parts of the Mediterranean. This couples the stratigraphic framework of the Greenland Ice core records as a regional stratotype, with  a number of tephra horizons in the North Atlantic and Europe, aiding the process of correlation. The last INTIMATE event stratigraphy coupled the extended GICC05 timescale for Greenland back to 128 b2k (Blockley et al., 2014). This paper reports on attempts to test the potential for tephrochronology to be extended into the Levant and potentially Arabia, through the identification of tephra layers in sediment focussing archives, such as archaeological cave sequences. We have examined tephra presence in archaeological sites, principally in Israel, that record sediment deposition from ~30ka BP through to >100ka BP. Analyses of these records show that tephra is present in almost all of the studied sites (e.g., Kebara, Tabun, Amud, Shovakh). Moreover, tephra in these sequences can be chemically correlated to known volcanic systems, demonstrating the potential going forward to analyse long lake and marine records around the region for cryptotephra. At the same time clear challenges are emerging. Firstly, there is a range of chemistry in many of the layers and careful analyses is needed to pick apart the geochemical signal and to identify reworking, as opposed to chemically heterogeneous ash layers from a single volcano. This process is complicated by the relatively limited range of published geochemical data from some volcanic centres. This presentation will outline the current state of knowledge of key volcanic centres, particularly in the Aegean and Turkey, alongside the new Levantine data, to consider the steps needed to establish a secure extension of the INTIMATE approach into this region.</p><p>Blockley, S., et al., 2014. Quaternary Science Reviews. 106, 88-100. doi:10.1016/j.quascirev.2014.11.002.</p>

scholarly journals Whales and Men: genetic inferences uncover a detailed history of hunting in bowhead whale

2020 ◽  
Author(s):  
TB Hoareau
Keyword(s):  
Population Change ◽  
Natural Populations ◽  
Late Glacial ◽  
Population History ◽  
Bowhead Whale ◽  
The Arctic ◽  
Arctic Seas ◽  
The North ◽  
Time Calibration ◽  
History Of

AbstractAfter millennia of hunting and a population collapse, it is still challenging to understand the genetic consequences of whaling on the circumarctic bowhead whale. Here I use published modern mtDNA sequences from the Bering-Chukchi-Beaufort population and a new time calibration to show that late–glacial climate changes and whaling have been the major drivers of population change. Cultures that hunted in the Arctic Seas from as early as 5000 years ago appear to be responsible for successive declines of the population growth, bringing the effective size down to 38% of its pristine population size. The Thules and the Basques (year 1000–1730) who only hunted in the North Atlantic had a major impact on this North Pacific population, indicating that bowhead whale stocks respond to harvesting as a single population unit. Recent positive growth is inferred only after the end of commercial whaling in 1915, and for levels of harvesting that are close to the current annual quota of 67 whales. By unfolding the population history of the bowhead whale, I provide compelling evidence that mtDNA yields critical yet undervalued information for management and conservation of natural populations.

scholarly journals How does the Arctic affect North Atlantic climate? Fresh perspectives on a long-standing question.

2021 ◽  
Author(s):  
Marilena Oltmanns ◽  
N. Penny Holliday ◽  
James Screen ◽  
D. Gwyn Evans ◽  
Simon A. Josey ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Heat Waves ◽  
Rapid Change ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Weather Extremes ◽  
Arctic Warming ◽  
The North ◽  
Arctic Ice

<p>Recent decades have been characterised by amplified Arctic warming and increased occurrence of extreme weather events in the North Atlantic region. While earlier studies noticed statistical links between high-latitude warming and mid-latitude weather extremes, the underlying dynamical connections remained elusive. Combining different data products, I will demonstrate a new mechanism linking Arctic ice losses with cold anomalies and storms in the subpolar region in winter, and with heat waves and droughts over Europe summer. Considering feedbacks of the identified mechanism on the Arctic Ocean circulation, I will further present new support for the potential of Arctic warming to trigger a rapid change in climate.</p>

Monitoring and Assessing Arctic Climate Change

2020 ◽  
Author(s):  
Lars-Otto Reiersen ◽  
Robert W. Corell
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Global Climate ◽  
Arctic Region ◽  
The Arctic ◽  
Sea Ice Extent ◽  
The North ◽  
Meteorological Observations ◽  
Arctic Climate Change ◽  
Global Systems

This overview of climate observation, monitoring, and research for the Arctic region outlines the key elements essential to an enhanced understanding of the unprecedented climate change in the region and its global influences. The first recorded observation of sea ice extent around Svalbard date back to the whaling activities around 1600. Over the following 300 years there are periodic and inadequate observations of climate and sea ice from explorers seeking a northern sea route for sailing to Asia or reaching the North Pole. Around 1900 there were few fixed meteorological stations in the circumpolar North. During the Second World War and the following Cold War, the observation network increased significantly due to military interest. Since the 1970s the use of satellites has improved the climate and meteorological observations of Arctic areas, and advancements in marine observations (beneath the sea surface and within oceanic sediments) have contributed to a much improved network of climate and meteorological variables. Climate change in the Arctic and its possible effects within the Arctic and on global climate such as extreme weather and sea level rise were first reported in the ACIA 2005 report. Since then there has been a lot of climate-related assessments based on data from the Arctic and ongoing processes within the Arctic that are linked to global systems.

Counting Harp Seals with ultra-violet photography

Polar Record ◽  
1976 ◽  
Vol 18 (114) ◽  
pp. 269-277 ◽  
Author(s):  
D. M. Lavigne
Keyword(s):  
North Atlantic ◽  
White Sea ◽  
North Atlantic Ocean ◽  
Ultra Violet ◽  
The Arctic ◽  
Hudson Bay ◽  
The North ◽  
Breeding Populations ◽  
Pagophilus Groenlandicus ◽  
Arctic Ice

The Harp Seal Pagophilus groenlandicus is a gregarious, migratory seal inhabiting Arctic and sub-Arctic waters of the North Atlantic Ocean. In spring, asthe ice recedes, the largest of three known breeding populations migrates up the east coas of Canada from the Gulf of St Lawrence, along the coast of Labrador, to the Canadian Archipelago, Hudson Bay, and the west coast of Greenland. After spending the summer feeding in Arctic waters, the seals move southward ahead of the Arctic ice pack, reaching the coast of Labrador and the Gulf of St Lawrence sometime in late December or early January. They reappear at the end of February and in early March in whelping ‘patches’ or concentrations on ice inthe Gulf of St Lawrence west of the Magdalen Islands, and off the coast of Labrador in an areaknown as the ‘Front’. One of the two smaller and probably distinct breeding populations is to be found in the White Sea, the other in the Vestisen [West Ice] between Jan Mayen and Svalbard.

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