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).

Precise radiocarbon dating of Late-Glacial cooling in mid-latitude South America

2003 ◽  
Vol 59 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Irka Hajdas ◽  
Georges Bonani ◽  
Patricio I. Moreno ◽  
Daniel Ariztegui
Keyword(s):  
South America ◽  
North Atlantic ◽  
Younger Dryas ◽  
Late Glacial ◽  
Short Term ◽  
Atlantic Region ◽  
Cold Event ◽  
Radiocarbon Age ◽  
The North ◽  
Younger Dryas Event

AbstractVariability of atmospheric 14C content often complicates radiocarbon-based chronologies; however, specific features such as periods of constant 14C age or steep changes in radiocarbon ages can be useful stratigraphic markers. The Younger Dryas event in the Northern Hemisphere is one of those periods, showing conspicuous 14C wiggles. Although the origin of those variations is not fully understood, we can make practical use of them and determine: (i) whether the Younger Dryas was global in extent; if so, (ii) were the initial cooling and the final warming synchronous worldwide; and (iii) what are the implications of these similarities/differences? Here we report high-resolution AMS 14C chronologies from the mid-latitudes of South America that pinpoint a cool episode between 11,400 and 10,20014C yr B.P. The onset of the final cool episode of the Late Glacial in the southern mid-latitudes, i.e., the Huelmo/Mascardi Cold Reversal, preceded the onset of the Younger Dryas cold event by ∼550 calendar years. Both events ended during a radiocarbon-age plateau at ∼10,20014C yr B.P. Thus, the Huelmo/Mascardi Cold Reversal encompasses the Younger Dryas, as well as a couple of short-term cool/warm oscillations that immediately preceded its onset in the North Atlantic region.

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.

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.

Late Glacial and Holocene history of Plešné Lake and its surrounding landscape based on pollen and palaeoalgological analyses

Biologia ◽  
2006 ◽  
Vol 61 (20) ◽  
Author(s):  
Vlasta Jankovská
Keyword(s):  
Late Glacial ◽  
Forest Steppe ◽  
Southern Europe ◽  
Pollen Diagram ◽  
History Of ◽  
The Bohemian Forest ◽  
Surrounding Landscape ◽  
Late Glacial And Holocene ◽  
High Degree ◽  
Biostratigraphic Units

AbstractPollen analysis has been carried out on a 549 cm thick sediment profile from lake Plešné jezero (Plešné Lake) in the Bohemian Forest (Šumava, Czech Republic; 1090 m a.s.l.; 48°47′ N; 13°52′ E). Analyses of 67 samples characterise the development of the lake biotope and the surrounding landscape during the last ca. 14,000 years. The pollen diagram shows a very distinct transition between the Late Glacial and the Holocene biostratigraphic units at a depth of ca. 312 cm. In the surroundings of Plešné Lake the vegetation was treeless during the entire Late Glacial. The alpine tree limit, formed by Betula and Pinus with undergrowth of shrubs, might have been at ca. 500 m a.s.l. Pollen transported from long distances was significant due to the openness of the landscape, coming from southern Europe and even Africa, and including high numbers of Artemisia, Poaceae, Chenopodiaceae, and some other herbs and shrubs from steppe and forest-steppe areas in southern Europe or Africa (likely Ephedra, certainly Lygeum spartum). The expansion of shrubs, particularly Juniperus, preceded the expansion of trees near the end of the Late Glacial. Afforestation of the region by thin stands of Betula and Pinus occurred during the Preboreal. Significant warming in the Boreal resulted in the expansion of Corylus, Quercetum mixtum (QM) trees, and probably also Picea and Alnus. Picea as well as QM trees were further expanding during the Early Atlantic. Picea was the dominant tree during the Late Atlantic and Fagus started to spread towards its end. Abrupt expansion of Abies marks the Subboreal. A high degree of afforestation (Abies, Fagus, Picea) was characteristic for the Early Subatlantic. During Late Subatlantic, pollen of synanthropic plants appears. Phases of the lake biotope development were defined on the basis of coccal green algae and Isoëtes.

Timing and duration of North American glacial lake discharges and the Younger Dryas climate reversal

2011 ◽  
Vol 75 (3) ◽  
pp. 541-551 ◽  
Author(s):  
John A. Rayburn ◽  
Thomas M. Cronin ◽  
David A. Franzi ◽  
Peter L.K. Knuepfer ◽  
Debra A. Willard
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
North American ◽  
Younger Dryas ◽  
Ice Cores ◽  
Cold Event ◽  
Lawrence Estuary ◽  
The North ◽  
The North Atlantic ◽  
Proglacial Lake

AbstractRadiocarbon-dated sediment cores from the Champlain Valley (northeastern USA) contain stratigraphic and micropaleontologic evidence for multiple, high-magnitude, freshwater discharges from North American proglacial lakes to the North Atlantic. Of particular interest are two large, closely spaced outflows that entered the North Atlantic Ocean via the St. Lawrence estuary about 13,200–12,900 cal yr BP, near the beginning of the Younger Dryas cold event. We estimate from varve chronology, sedimentation rates and proglacial lake volumes that the duration of the first outflow was less than 1 yr and its discharge was approximately 0.1 Sv (1 Sverdrup = 106 m3 s−1). The second outflow lasted about a century with a sustained discharge sufficient to keep the Champlain Sea relatively fresh for its duration. According to climate models, both outflows may have had sufficient discharge, duration and timing to affect meridional ocean circulation and climate. In this report we compare the proglacial lake discharge record in the Champlain and St. Lawrence valleys to paleoclimate records from Greenland Ice cores and Cariaco Basin and discuss the two-step nature of the inception of the Younger Dryas.

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.

Episode of Strengthened Summer Monsoon Climate of Younger Dryas Age on the Loess Plateau of Central China

1993 ◽  
Vol 39 (1) ◽  
pp. 45-54 ◽  
Author(s):  
An Zhisheng ◽  
Stephen C. Porter ◽  
Zhou Weijian ◽  
Lu Yanchou ◽  
Douglas J. Donahue ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
General Circulation ◽  
Younger Dryas ◽  
Circulation Model ◽  
Late Glacial ◽  
Central China ◽  
Monsoon Circulation ◽  
The Tibetan Plateau ◽  
Monsoon Climate ◽  
Younger Dryas Event

AbstractThe Baxie loess section, just east of the Tibetan Plateau, contains evidence showing that the Asian monsoon climate experienced an abrupt reversal near the end of the last glacial age. Rapid deposition of dust under cool, dry full-glacial conditions gave way to an interval of soil development and reduced dust influx attributed to a strengthening of the warm, moist summer monsoon. A subsequent abrupt increase in dust deposition, a response to a weakening of the summer monsoon, was later followed by renewed soil formation as summer monsoon circulation again intensified during the early Holocene. By one interpretation, the thin upper loess is a manifestation of the European Younger Dryas oscillation; however, in this case the available 14C ages require either that (1) onset of loess deposition lagged the beginning of the Younger Dryas event in Europe by as much as 2000 calibrated 14C years or (2) all the 14C ages are too young, possibly due to contamination. Alternatively, the late-glacial paleosol, the top of which is synchronous with the abrupt end of the late-glacial δ18O anomaly in the Dye 3 Greenland ice core, records the Younger Dryas event. Such an interpretation is consistent with general circulation model simulations of Younger Dryas climate that show strong seasonality and a strengthened summer monsoon, and with marine cores from the western Pacific Ocean that contain evidence of pronounced cooling of surface waters during Younger Dryas 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.

ELIZABETH SAVAGE, A Gateway to Hell, a Gateway to Paradise: The North African Response to the Arab Conquest, Studies in Late Antiquity and Early Islam, no. 7 (Princeton, N.J.: Darwin Press, 1997). $35 cloth.

2000 ◽  
Vol 32 (2) ◽  
pp. 282-284
Author(s):  
Mahmood Ibrahim
Keyword(s):  
Iberian Peninsula ◽  
Late Antiquity ◽  
North African ◽  
The North ◽  
Early Islam ◽  
History Of ◽  
In The Beginning ◽  
Umayyad Caliphate ◽  
The Way

It was only after Abd al-Malik ibn Marwan regained the Umayyad caliphate that concerted efforts were made to extend Umayyad sway into the Maghrib. These efforts turned into a wave of expansion that extended all the way into the 2nd century A.H./8th century A.D. and reached far into the Iberian Peninsula and across the Pyrenees. These efforts also constitute the history of the Maghrib, a history aptly described by the title of the book under review: A Gateway to Hell, a Gateway to Paradise. This title reflects the conflicted attitudes held by early Muslims regarding the region and its history. In the beginning, Umayyad policies were indeed contradictory. For example, Tariq ibn Ziyad, a Berber, could lead Muslims into the Iberian Peninsula, while up to a time Damascus considered Berbers legal booty.

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