A late-glacial – Holocene palaeoecological record from Pye Lake on the eastern shore of Nova Scotia, CanadaGeological Survey of Canada Contribution 20080395.

2009 ◽  
Vol 46 (9) ◽  
pp. 637-650 ◽  
Author(s):  
Robert J. Mott ◽  
Ian R. Walker ◽  
Samantha L. Palmer ◽  
Martin Lavoie
Keyword(s):  
Nova Scotia ◽  
Younger Dryas ◽  
Late Glacial ◽  
Forest Composition ◽  
Eastern Shore ◽  
The North ◽  
Tundra Vegetation ◽  
History Of ◽  
Climatic History ◽  
Recent Sediments

Pollen and chironomid analyses and radiocarbon dating at Pye Lake on the eastern shore of Nova Scotia are used to outline the vegetation and climatic history of the area. The coast was deglaciated prior to ∼12 200 14C BP (14 300 cal BP), and herbaceous tundra vegetation invaded the area. Midge-inferred maximum summer surface-water temperatures in the lake ranged between 9 and 11 °C. Subsequent gradual warming to ∼18 °C by 10 800 14C BP (12 725 cal BP) favoured the migration of a variety of herbaceous and shrub taxa into the region. Rapid cooling to ∼10 °C saw vegetation revert to herbaceous tundra communities. This interval, related to the Younger Dryas cold interval of the North Atlantic and Europe, lasted until ∼10 000 14C BP (11 630 cal BP). The climate then warmed again to conditions similar to those that prevailed immediately before onset of Younger Dryas cooling. Further warming saw successive tree species migrate into the area until, by the mid-Holocene, the forests contained most of the taxa prevalent today. Since ∼3500 years ago, cooling of the climate has favoured conifer species over broad-leaved taxa. Agriculture and logging practices in the last 150 years have altered the forest composition, but pollen analysis of the most recent sediments cannot resolve these changes adequately.

Climatic Change on the Iberian Peninsula Recorded in a 30,000-Yr Pollen Record from Lake Banyoles

1994 ◽  
Vol 41 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Ramon Pèrez-Obiol ◽  
Ramon Julià
Keyword(s):  
Iberian Peninsula ◽  
Younger Dryas ◽  
Late Glacial ◽  
Pollen Record ◽  
Cold Event ◽  
Pollen Diagram ◽  
Climatic Oscillations ◽  
The North ◽  
History Of ◽  
Younger Dryas Event

AbstractThe Banyoles lacustrine sequence shows that the vegetational history of the northeastern Iberian Peninsula during the last 30,000 yr follows the North Atlantic pattern of climatic oscillations. The Banyoles pollen diagram, supported by two calibrated 14C dates and nine U/Th dates, shows a clear interstadial event between 30,000 and 27,000 yr B.P., a Pleniglacial period with minor oscillations that ended abruptly ca. 14,420 ± 410 yr B.P., and a late-glacial sequence that records the classical stages described in Northern Europe: the Bølling-Allerød Interstade, the Younger Dryas event at 12,000 yr B.P. (U-series age), and a short warming phase between the Younger Dryas and the last cold event (dated at 11,000 yr B.P., U-series age).

Late-glacial (Allerød – Younger Dryas) Coleoptera from central Cape Breton Island, Nova Scotia, Canada

1997 ◽  
Vol 34 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Randall F. Miller
Keyword(s):  
Nova Scotia ◽  
Boreal Forest ◽  
Younger Dryas ◽  
Ground Cover ◽  
Late Glacial ◽  
Polar Front ◽  
Climate Data ◽  
Cape Breton Island ◽  
The North ◽  
Cape Breton

Coleoptera from three late-glacial sites on Cape Breton Island, Nova Scotia, Canada, provide proxy climate data from 12 600 to 10 400 BP. Samples older than about 11 800 BP contain tundra to tree-line species. Between 11 800 and about 10 800 BP, beetle assemblages become typical of the modern boreal forest. Beetles younger than 10 800 BP responded to climatic deterioration during the Younger Dryas. Although coleopteran evidence for the Younger Dryas is not as strong as that presented by palynological and stratigraphic studies, the appearance of Olophrum boreale and other species found today in the northern boreal forest and on tundra or coastal tundra corresponds with the decline of shrub birch and the rise in willow and alder pollen. Beetles responded just as likely to changes in vegetation and ground cover as to changes in temperature. The extent to which Coleoptera were affected may lie somewhere between a moderated continental response seen in the Great Lakes region in North America and more extreme changes recorded in Europe. This response is consistent with shifts in the North Atlantic oceanic Polar Front in the Ruddiman and McIntyre model.

Holocene and latest Pleistocene fluctuations of Stutfield Glacier, Canadian Rockies

2001 ◽  
Vol 38 (8) ◽  
pp. 1141-1155 ◽  
Author(s):  
G D Osborn ◽  
B J Robinson ◽  
B H Luckman
Keyword(s):  
19Th Century ◽  
18Th Century ◽  
Late Glacial ◽  
Ice Age ◽  
Late 19Th Century ◽  
Canadian Rockies ◽  
The Holocene ◽  
The North ◽  
History Of ◽  
Glacier Advance

The Holocene and late glacial history of fluctuations of Stutfield Glacier are reconstructed using moraine stratigraphy, tephrochronology, and dendroglaciology. Stratigraphic sections in the lateral moraines contain tills from at least three glacier advances separated by volcanic tephras and paleosols. The oldest, pre-Mazama till is correlated with the Crowfoot Advance (dated elsewhere to be Younger Dryas equivalent). A Neoglacial till is found between the Mazama tephra and a paleosol developed on the Bridge River tephra. A log dating 2400 BP from the upper part of this till indicates that this glacier advance, correlated with the Peyto Advance, culminated shortly before deposition of the Bridge River tephra. Radiocarbon and tree-ring dates from overridden trees exposed in moraine sections indicate that the initial Cavell (Little Ice Age (LIA)) Advance overrode this paleosol and trees after A.D. 1271. Three subsequent phases of the Cavell Advance were dated by dendrochronology. The maximum glacier extent occurred in the mid-18th century, predating 1743 on the southern lateral, although ice still occupied and tilted a tree on the north lateral in 1758. Subsequent glacier advances occurred ca. 1800–1816 and in the late 19th century. The relative extent of the LIA advances at Stutfield differs from that of other major eastward flowing outlets of the Columbia Icefield, which have maxima in the mid–late 19th century. This is the first study from the Canadian Rockies to demonstrate that the large, morphologically simple, lateral moraines defining the LIA glacier limits are actually composite features, built up progressively (but discontinuously) over the Holocene and contain evidence of multiple Holocene- and Crowfoot-age glacier advances.

Simulating Past and Forecasting Future Climates

1993 ◽  
Vol 20 (4) ◽  
pp. 339-346 ◽  
Author(s):  
Reid A. Bryson
Keyword(s):  
Carbon Dioxide ◽  
Global Climate ◽  
Rapid Change ◽  
Carbon Dioxide Content ◽  
Volcanic Origin ◽  
The North ◽  
The Earth ◽  
History Of ◽  
Climatic History ◽  
Volcanic Aerosols

Climatic change is not a new phenomenon, nor is it random, as most of the variation can be explained in terms of variations in the sunlight reaching the surface of the Earth. The solar energy reaching the surface is modified by the aerosols in the atmosphere, however, and that means primarily aerosols of volcanic origin.The climatic history of the Earth is divided up into episodes with abrupt beginnings and ends. Rapid changes from one climatic state to another are normal. The fluctuations within this century do not appear to be unusual in any respect.To the Author's knowledge there is no evidence that past climatic changes, including those of the last decades, are related to changes in carbon dioxide in the atmosphere—except perhaps for warmer nights in the North American mid-west. It is not possible to simulate past climates using carbon dioxide content as the main variable, but it is possible to do so using calculated solar radiation as modified by volcanic aerosols. This strongly suggests that forecasts of the climatic future based on carbon dioxide increases are suspect.Computerized models of the climate that can simulate decadal and century-long variations of climate as well as variations on the millennium scale, suggest that the climate will not warm dramatically in the next fifty years, but will, rather soon after that, begin a rather rapid change towards the next glacial climate.Changes in our global array of cultures, sufficient to affect the global climate in a way which we perceive as beneficial, probably are not possible within centuries without massive physical conflict. There are both winners and losers when the climate changes in a non-uniform pattern, as it always does. It is a well-known fact that a global change of 0.5°C in mean temperature, such as has happened in recent years, might produce some regions of 10°C change in either direction and some regions with no change at all, and additionally an array of rainfall changes of various magnitudes. Russians would welcome warming of their climate!The problems with attempting to modify the global climate in a particular direction are enormous and would be incredibly costly. This is compounded by our not knowing what the climate would do without intervention. Only one thing is truly clear, and it is that the present knowledge of the climatic effect of changing carbon dioxide content of the atmosphere is totally inadequate as a basis for initiating any global attempt to change the climate.The indicated action would appear to be to engage in some high-quality climatic research based on sound science before taking global risks greater than those that might arise from the putative ‘global warming’.

Late Weichselian Environmental History in Southeastern Sweden during the Deglaciation of the Scandinavian Ice Sheet

1987 ◽  
Vol 28 (1) ◽  
pp. 1-37 ◽  
Author(s):  
Svante Björck ◽  
Per Möller
Keyword(s):  
Environmental History ◽  
Vegetation Change ◽  
Time Lag ◽  
Ice Sheet ◽  
Late Glacial ◽  
Climatic Data ◽  
Basal Ice ◽  
Tundra Vegetation ◽  
History Of ◽  
Late Weichselian

AbstractLate Weichselian litho-, bio-, and chronostratigraphy (14C and varves) in southeastern Sweden provide a detailed picture of the deglaciation pattern and dynamics, shore displacement, late-glacial sedimentation, and history of the landscape, vegetation, and climate. Two plausible glacial models were tested against lithologic, chronologic, and climatic data. Permafrost at and outside the ice margin and topographic conditions beneath the ice apparently caused inward spread of frozen glacier-bed conditions. This led to a buildup of a large zone of debris-rich basal ice. A climatic amelioration about 12,700 yr B.P. changed the temperature profile in the ice sheet. Deposition of basal melt-out till began at the previously frozen glacier bed, and a rapid recession of the clean ice set in; thin exposed debris-rich basal ice which was separated from the active ice margin about 150 yr later. In this zone of stagnant ice there followed a 200– 300-yr period marked by subglacial and supraglacial melt-out and resedimentation, forming a large hummocky/transverse moraine. The mild climate favored rapid plant immigration, and a park-tundra was established. The gradual closing of the landscape was interrupted by a 100- to 150-yr period of tundra vegetation and a cool, dry climate, with local vegetational differences caused by differences in soil moisture. About 12,000 yr B.P. a second climatic amelioration set in, and during the next 1000 yr a birch (and pine) woodland gradually developed. Soils stabilized and Empetrum heaths became abundant as the climate gradually deteriorated at the end of this period. By 11,000 yr B.P. the area had become a tundra again with scattered birch stands, dominated by herbs such as Artemisia, Chenopodiaceae, grasses, and sedges. Some 500 yr later a birch/pine woodland again succeeded, and within about 500 yr the vegetation changed to a rather closed woodland as the climate ameliorated further. However, the time lag between climatic and vegetation change was considerable.

Allerød–Younger Dryas Coleoptera from western Cape Breton Island, Nova Scotia, Canada

1996 ◽  
Vol 33 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Randall F. Miller
Keyword(s):  
Nova Scotia ◽  
Younger Dryas ◽  
Late Glacial ◽  
Cold Climate ◽  
Western Cape ◽  
Cape Breton Island ◽  
Cape Breton ◽  
Beetle Assemblages ◽  
Climate Indicator ◽  
Younger Dryas Event

Studies of Coleoptera remains from two late-glacial sites on Cape Breton Island, Nova Scotia, Canada, present a picture of the paleoenvironment and paleoclimate during the Allerød–Younger Dryas transition in the Maritimes region. They provide evidence for the Younger Dryas event in northeastern North America. Between 11 300 and 10 800 BP, the beetle assemblages at the Campbell site are typical of faunas of the modern middle to northern boreal forest. The West Mabou site contains beetle fossils younger than 10 900 BP, possibly as young as 10 500 BP, extending into the time period of the Younger Dryas, dated from 10 800 to 10 000 BP in the Maritimes. A "cold climate" indicator recognizable in the beetle fauna, Olophrum boreale, occurs in relative abundance and provides an interesting comparison with sites in Europe where the same northern boreo-montane species is evident at the beginning of the Younger Dryas.

Pollen and Oxygen Isotope Analyses on Late- and Post-Glacial Sediments of the Tourbière de Chirens (Dauphiné, France)

1981 ◽  
Vol 15 (2) ◽  
pp. 160-170 ◽  
Author(s):  
U. Eicher ◽  
U. Siegenthaler ◽  
S. Wegmüller
Keyword(s):  
Pollen Analysis ◽  
Younger Dryas ◽  
Late Glacial ◽  
Glacial Sediments ◽  
Abrupt Changes ◽  
Climatic Transition ◽  
Climatic History ◽  
The Alps ◽  
Short Time ◽  
Isotope Analyses

AbstractThe sequence of vegetation phases in the late Glacial was studied in a sediment section from the bog Tourbière de Chirens by means of pollen analysis. 18O/16O ratios of samples of lacustrine marl, obtained from the same profile, reflect variations of 18O/16O in precipitation and thus provide an additional, independent paleoclimatic record. The observed 18O/16O variations agree well with the climatic history as deduced from pollen analysis. The climatic transition from the Oldest Dryas to the Bølling period sensu lato, as well as the beginning and end of the Younger Dryas cold phase, is marked by abrupt changes in the 18O/16O ratio which were observed also in other regions of the Alps. These drastic climatic changes probably took place simultaneously over large areas of Central Europe and occurred within short time spans.

Late Pleistocene and early Holocene environmental history of southwestern Washington State, U.S.A.

1984 ◽  
Vol 21 (6) ◽  
pp. 619-629 ◽  
Author(s):  
Cathy W. Barnosky
Keyword(s):  
Environmental History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Cascade Range ◽  
Early Holocene ◽  
Olympic Mountains ◽  
Tundra Vegetation ◽  
Plant Remains ◽  
History Of ◽  
Glacial Time

A comparison of pollen records and associated plant remains from sites along a major precipitation gradient in southwestern Washington enables reconstruction of the late Quaternary environment during glacial and early Holocene time. During the Evans Creek Stade (25 000 – 17 000 years BP) little moisture reached lowlands east of the Olympic Mountains and as a result both the Puget Trough and the Columbia Basin featured a cold dry climate and parkland–tundra vegetation In glacial time, greatest aridity seems to have occurred between 19 000 and 17 000 years BP. After 17 000 years BP the development of mesophytic subalpine parkland suggests that maritime conditions extended farther east into the Puget Trough, and the Cascade Range became an important precipitation divide. Conditions warmer and (or) drier than today developed throughout western Washington between 10 000 and 8000–6000 years BP. Vegetation on opposite sides of the Cascade Range became dissimilar as early as 17 000 years BP, but this trend was accentuated in late glacial and early Holocene time.

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 Palynology and Archaeology of Late Vistulian and Early Holocene Sites in Lubuskie Lake District, Western Poland

2014 ◽  
Vol 31 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Iwona Okuniewska-Nowaczyk ◽  
Iwona Sobkowiak-Tabaka
Keyword(s):  
Small Area ◽  
Younger Dryas ◽  
Late Glacial ◽  
Early Holocene ◽  
Lake District ◽  
Multidisciplinary Research ◽  
Late Vistulian ◽  
Palynological Spectrum ◽  
History Of ◽  
Palynological Records

Abstract The Lubuskie Lake District played an important part in recolonisation of the Polish Plain due to its location and the character of the terrain. Despite that, it is and especially its northern part, poorly explored regarding both history of Late Glacial and early Holocene settlements, and the natural environment. The paper presents results of multidisciplinary research in this area. The most spectacular discoveries were connected with remains of settlements of the Hamburgian culture societies at Myszęcin - currently the richest site of this culture over the entire North European Plain. In the vicinity of this site several Late Palaeolithic and Mesolithic settlements of varied functions were recorded. First palynological records came from the Younger Dryas sediments in this area. In a log with a palynological spectrum comprising Younger Dryas and the beginning of the Holocene, a charcoal dust was found and it could indicate human activity as humans lived at a lake shore. An important complement to the image of the Late Glacial settlement at the Lubuskie Lake District was provided by the research near Lubrza that resulted in data regarding settlements of the Federmesser and Świderian culture societies. This region was not typical in a palynological spectrum of deposits during Allerød but also indicated highly diversified thickness of basal peat in a small area.

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