A multi-disciplinary macrofossil study of late glacial to early Holocene sediments from Søndre Kobberdam, Hareskovene, Denmark

During the early part of the Allerød period, from c. 13 600 to 13 330 years BP, unstable soils with a tundra-like open, treeless vegetation with Betula nana and Dryas octopetala were found around Søndre Kobberdam in Hareskovene. Open Betula pubescens woodland was not established until the middle Allerød about 13 330 years BP. During the Younger Dryas, Betula nana and Dryas octopetala spread again, and Betula pubescens almost disappeared. From the onset of the Holocene warming an open tundra landscape characterised the area. About 11 300 years BP Betula pubescens started to recolonise the region and Populus tremula and Pinus sylvetris arrived at c. 11 000 years BP, replacing the open landscape by woodland. Along the margin of the lake Carex paniculata, Carex riparia and Cladium mariscus were growing. The lake fauna included a rich and diverse fauna of molluscs that thrived in the carbonate-rich waters. We did not find any evidence for the local presence of Pinus sylvestris during the late glacial.

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A major hydrobiological change in Dasht-e Arjan Wetland (southwestern Iran) during the late glacial – early Holocene transition revealed by subfossil chironomids

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2018-0256 ◽

2019 ◽

Vol 56 (8) ◽

pp. 848-856

Author(s):

Cyril Aubert ◽

Morteza Djamali ◽

Matthew Jones ◽

Hamid Lahijani ◽

Nick Marriner ◽

...

Keyword(s):

Lake Level ◽

Regional Scale ◽

Younger Dryas ◽

Late Glacial ◽

Early Holocene ◽

Geochemical Data ◽

The Holocene ◽

Chironomus Plumosus ◽

Subfossil Chironomids ◽

Southwestern Iran

The late glacial – early Holocene transition is a key period in the earth’s history. However, although this transition is well studied in Europe, it is not well constrained in the Middle East and palaeohydrological records with robust chronologies remain scarce from this region. Here we present an interesting hydrobiological record showing a major environmental change occurring in the Dasht-e Arjan Wetland (southwestern Iran, near to Persepolis) during the late glacial – early Holocene transition (ca. 11 650 years cal BP). We use subfossil chironomids (Insecta: Diptera) as a proxy for hydrological changes and to reconstruct lake-level fluctuations. The Arjan wetland was a deep lake during the Younger Dryas marked by a dominance of Chironomus plumosus/anthracinus-type, taxa adapted to anoxic conditions of deep waters. At the beginning of the Holocene, a drastic decrease (more than 80% to less than 10%) of Chironomus plumosus/anthracinus-type, combined with diversification of littoral taxa such as Polypedilum nubeculosum-type, Dicrotendipes nervosus-type, and Glyptotendipes pallens-type, suggests a lake-level decrease and a more vegetalized aquatic environment. We compare and contrast the chironomid record of Arjan with a similar record from northwestern Iran. The palaeoclimatic significance of the record, at a local and regional scale, is subsequently discussed. The increase in Northern Hemisphere temperatures, inferred by geochemical data from NGRIP, at the beginning of the Holocene best explains the change from the Younger Dryas highstand to early Holocene lowstand conditions in the Dasht-e Arjan wetland. However, a contribution of the meltwater inflow from small local glaciers in the catchment basin is not excluded.

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Reconstruction of vegetation in the foothills of the Carpathian Mountains, Gorgany region, in the late glacial (based on pollen data of peat-bog Pidluzhia)

Visnyk of the Lviv University. Series Geography ◽

10.30970/vgg.2015.49.8652 ◽

2015 ◽

pp. 333-340

Author(s):

Natalia Chumak

Keyword(s):

Key Words ◽

Radiocarbon Dating ◽

Environmental Changes ◽

Younger Dryas ◽

Late Glacial ◽

Peat Bog ◽

Pollen Data ◽

Carpathian Mountains ◽

The Holocene ◽

Short Period

The environmental changes on short-period stages of the Late Glacial were reconstructed based on pollen data of peat-bog Pidluzhia deposits and their radiocarbon dating. There are the Older and Younger Dryas, the Allerod (three phases) are allocated on palynological data in the Late Glacial. Vegetation had evolved from cold meadows to pine forest during this time. The transition from the Late Glacial to the Holocene was identified by the emergence of broad-leaved trees (elm, oak and linden), the spreading of spruce and disappearance of xerophytic elements. Key words: paleovegetation, paleoclimate, palinology, the Late Glacial, the foothills of the Carpathian Mountains.

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12,000–11,700 cal BP

10.1093/oso/9780199329199.003.0002 ◽

2017 ◽

Cited By ~ 1

Author(s):

Ofer Bar-Yosef ◽

Miryam Bar-Matthews ◽

Avner Ayalon

Keyword(s):

Spatial Organization ◽

Younger Dryas ◽

Late Glacial ◽

Glacial Maximum ◽

Food Sources ◽

Climatic Fluctuations ◽

The Holocene ◽

Fertile Crescent ◽

First Millennium ◽

Terminal Pleistocene

We take up the question of “why” cultivation was adopted by the end of the Younger Dryas by reviewing evidence in the Levant, a sub-region of southwestern Asia, from the Late Glacial Maximum through the first millennium of the Holocene. Based on the evidence, we argue that the demographic increase of foraging societies in the Levant at the Terminal Pleistocene formed the backdrop for the collapse of foraging adaptations, compelling several groups within a particular “core area” of the Fertile Crescent to become fully sedentary and introduce cultivation alongside intensified gathering in the Late Glacial Maximum, ca. 12,000–11,700 cal BP. In addition to traditional hunting and gathering, the adoption of stable food sources became the norm. The systematic cultivation of wild cereals begun in the northern Levant resulted in the emergence of complex societies across the entire Fertile Crescent within several millennia. Results of archaeobotanical and archaeozoological investigations provide a basis for reconstructing economic strategies, spatial organization of sites, labor division, and demographic shifts over the first millennium of the Holocene. We draw our conclusion from two kinds of data from the Levant, a sub-region of southwestern Asia, during the Terminal Pleistocene and early Holocene: climatic fluctuations and the variable human reactions to natural and social calamities. The evidence in the Levant for the Younger Dryas, a widely recognized cold period across the northern hemisphere, is recorded in speleothems and other climatic proxies, such as Dead Sea levels and marine pollen records.

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Processing of pine (Pinus sylvestris) and birch (Betula pubescens) leaf material in a small river system in the northern Cairngorms, Scotland

Hydrology and Earth System Sciences ◽

10.5194/hess-8-567-2004 ◽

2004 ◽

Vol 8 (3) ◽

pp. 567-577 ◽

Cited By ~ 15

Author(s):

P. Collen ◽

E. J. Keay ◽

B. R. S. Morrison

Keyword(s):

Pinus Sylvestris ◽

Woody Debris ◽

River System ◽

Betula Pubescens ◽

Pine Needles ◽

Small River ◽

Leaf Packs ◽

Leaf Processing ◽

North Eastern

Abstract. Processing rates, and macroinvertebrate colonisation, of pine needles and birch leaves were studied at eight sites on the river Nethy, a small river system in the Cairngorm region of north-eastern Scotland. Throughout this river system, processing rates were slow for pine (k values 0.0015-0.0034 day-1) and medium to fast for birch (k values 0.0085-0.0331 day-1). Plecopteran shredders dominated both pine and birch leaf packs during the early part of the experiment while chironomids were more important in the latter stages. It is suggested that the slow processing rate of pine needles could adversely affect the productivity of streams, particularly where needles provide the major allochthonous energy source and retentive features are limited. Forest managers should consider this when creating new pinewoods in treeless areas as it will take many years for the trees to reach a size at which they can effectively contribute retentive features, in the form of woody debris, to streams. Keywords: leaf processing, pine needles, shredders, Pinus sylvestris, Betula pubescens, Scotland.

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Fluctuations of Outlet and Valley Glaciers in the Southern Andes (Argentina) during the Past 13,000 Years

Quaternary Research ◽

10.1006/qres.1999.2043 ◽

1999 ◽

Vol 51 (3) ◽

pp. 238-247 ◽

Cited By ~ 62

Author(s):

Gerd Wenzens

Keyword(s):

Younger Dryas ◽

Late Glacial ◽

The South ◽

Southern Andes ◽

Outlet Glacier ◽

The Holocene ◽

The Past ◽

Late Glacial And Holocene ◽

Glacial Time

AbstractIn the southern Argentine Andes, ten advances of valley glaciers were used to reconstruct the late-glacial and Holocene glacier history. The accumulation areas of these glaciers lie in the Precordillera and are thus independent of fluctuations of the South Patagonian Icefield. Like the Viedma outlet glacier, the valley glaciers advanced three times during late-glacial time (14,000–10,000 yr B.P.). The youngest advance correlates with the Younger Dryas Stade, based on two minimum AMS14C dates of 9588 and 9482 yr B.P. The second oldest advance occurred before 11,800 yr B.P. During the first half of the Holocene, (ca. 10,000–5000 yr B.P.), advances culminated about 8500, 8000–7500, and 5800–5500 yr B.P. During the second half of the Holocene, advances occurred between ca. 4500 and 4200 yr B.P., as well as between 3600 and 3300 yr B.P. In the Rı́o Cóndor valley three subsequent advances have been identified.

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Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

Quaternary Research ◽

10.1016/j.yqres.2007.12.002 ◽

2008 ◽

Vol 69 (2) ◽

pp. 263-275 ◽

Cited By ~ 30

Author(s):

R. Scott Anderson ◽

Renata B. Jass ◽

Jaime L. Toney ◽

Craig D. Allen ◽

Luz M. Cisneros-Dozal ◽

...

Keyword(s):

New Mexico ◽

Pinus Ponderosa ◽

Late Glacial ◽

Conifer Forest ◽

Lake Levels ◽

Mixed Conifer ◽

The Holocene ◽

Groundwater Levels ◽

Mixed Conifer Forest ◽

Jemez Mountains

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. AnArtemisiasteppe, then an openPiceawoodland grew around a small pond until ca. 11,700 cal yr BP whenPinus ponderosabecame established. C/N ratios,δ13C andδ15N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

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Die spät- und frühpostglaziale Vegetationsentwicklung im Umkreis der Alpen. Bemerkungen zur Arbeit von H. Zoller: „Pollenanalystische Untersuchungen zur Vegetationsgeschichte der insurbischen Schweiz“, 1960

E&G Quaternary Science Journal ◽

10.3285/eg.12.1.02 ◽

1962 ◽

Vol 12 (1) ◽

pp. 9-17

Author(s):

Gerhard Lang

Keyword(s):

Younger Dryas ◽

Late Glacial ◽

Climatic Oscillation ◽

Northern Border ◽

The Alps ◽

Southern Border

Abstract. Based upon newer papers a brief summary is given on Late-glacial and Pre-boreal vegetational history at the western and northern border of the Alps; the effects of the Bölling- and especially the Alleröd-oscillation are demonstrated. Proceeding of that the different results by H. Zoller (I960) in Southern Switzerland are examined and the arguments for another dating of his two Late-glacial pollen diagramms are discussed. According to that the first afforestation in the lowlands at the southern border of the Alps occured not in the Allerod but already in the Boiling period; the „Piottino-oscillation", associated with the Gschnitz-Stadium, is probably not a new discovered Pre-boreal climatic oscillation, but corresponds to the Alleröd-oscillation. Therefore it seems not necessary to doubt the synchronism of Younger Dryas and Schlußvereisung in the Alps.

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