Western Siberia experienced rapid shifts in moisture source and summer water balance during the last deglaciation and early Holocene

2021 ◽  
Author(s):  
Owen C. Cowling ◽  
Elizabeth K. Thomas ◽  
John Inge Svendsen ◽  
Jan Mangerud ◽  
Haflidi Haflidason ◽  
...  
Keyword(s):  
Water Balance ◽  
Western Siberia ◽  
Early Holocene ◽  
Last Deglaciation ◽  
Moisture Source ◽  
The Last Deglaciation

scholarly journals Deglacial and Holocene vegetation and climatic changes in the southern Central Mediterranean from a direct land–sea correlation

2013 ◽  
Vol 9 (2) ◽  
pp. 767-787 ◽  
Author(s):  
S. Desprat ◽  
N. Combourieu-Nebout ◽  
L. Essallami ◽  
M. A. Sicre ◽  
I. Dormoy ◽  
...  
Keyword(s):  
Winter Precipitation ◽  
Climatic Changes ◽  
Early Holocene ◽  
Last Deglaciation ◽  
Central Mediterranean ◽  
The Holocene ◽  
Southern Central ◽  
The Last Deglaciation ◽  
The Mediterranean ◽  
Trees And Shrubs

Abstract. Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, including in the southern Central Mediterranean. In this paper, we present a new marine pollen sequence (core MD04-2797CQ) from the Siculo-Tunisian Strait documenting the regional vegetation and climatic changes in the southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the southern Central Mediterranean between 18.2 and 12.3 ka cal BP, indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI)-1. Across the transition Greenland Stadial (GS)-1 – Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 ka cal BP. This record underlines with no chronological ambiguity that even though temperatures increased, deficiency in moisture availability persisted into the early Holocene. Temperate trees and shrubs with heath underbrush or maquis expanded between 10.1 and 6.6 ka, corresponding to Sapropel 1 (S1) interval, while Mediterranean plants only developed from 6.6 ka onwards. These changes in vegetal cover show that the regional climate in southern Central Mediterranean was wetter during S1 and became drier during the mid- to late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modeling experiments, that the early Holocene increased melting of the Laurentide Ice Sheet in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediterranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidence for centennial-scale vegetation and climatic changes in the southern Central Mediterranean. During the wet early Holocene, alkenone-derived cooling episodes are synchronous with herbaceous composition changes that indicate muted changes in precipitation. In contrast, enhanced aridity episodes, as detected by strong reduction in trees and shrubs, are recorded during the mid- to late Holocene. We show that the impact of the Holocene cooling events on the Mediterranean hydroclimate depend on baseline climate states, i.e. insolation and ice sheet extent, shaping the response of the mid-latitude atmospheric circulation.

scholarly journals Holocene thinning of Darwin and Hatherton glaciers, Antarctica, and implications for grounding-line retreat in the Ross Sea

2021 ◽  
Vol 15 (7) ◽  
pp. 3329-3354
Author(s):  
Trevor R. Hillebrand ◽  
John O. Stone ◽  
Michelle Koutnik ◽  
Courtney King ◽  
Howard Conway ◽  
...  
Keyword(s):  
Catchment Area ◽  
Ross Sea ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Early Holocene ◽  
Last Deglaciation ◽  
Grounding Line ◽  
The Last Deglaciation ◽  
Transantarctic Mountains ◽  
Exposure Ages

Abstract. Chronologies of glacier deposits in the Transantarctic Mountains provide important constraints on grounding-line retreat during the last deglaciation in the Ross Sea. However, between Beardmore Glacier and Ross Island – a distance of some 600 km – the existing chronologies are generally sparse and far from the modern grounding line, leaving the past dynamics of this vast region largely unconstrained. We present exposure ages of glacial deposits at three locations alongside the Darwin–Hatherton Glacier System – including within 10 km of the modern grounding line – that record several hundred meters of Late Pleistocene to Early Holocene thickening relative to present. As the ice sheet grounding line in the Ross Sea retreated, Hatherton Glacier thinned steadily from about 9 until about 3 ka. Our data are equivocal about the maximum thickness and Mid-Holocene to Early Holocene history at the mouth of Darwin Glacier, allowing for two conflicting deglaciation scenarios: (1) ∼500 m of thinning from 9 to 3 ka, similar to Hatherton Glacier, or (2) ∼950 m of thinning, with a rapid pulse of ∼600 m thinning at around 5 ka. We test these two scenarios using a 1.5-dimensional flowband model, forced by ice thickness changes at the mouth of Darwin Glacier and evaluated by fit to the chronology of deposits at Hatherton Glacier. The constraints from Hatherton Glacier are consistent with the interpretation that the mouth of Darwin Glacier thinned steadily by ∼500 m from 9 to 3 ka. Rapid pulses of thinning at the mouth of Darwin Glacier are ruled out by the data at Hatherton Glacier. This contrasts with some of the available records from the mouths of other outlet glaciers in the Transantarctic Mountains, many of which thinned by hundreds of meters over roughly a 1000-year period in the Early Holocene. The deglaciation histories of Darwin and Hatherton glaciers are best matched by a steady decrease in catchment area through the Holocene, suggesting that Byrd and/or Mulock glaciers may have captured roughly half of the catchment area of Darwin and Hatherton glaciers during the last deglaciation. An ensemble of three-dimensional ice sheet model simulations suggest that Darwin and Hatherton glaciers are strongly buttressed by convergent flow with ice from neighboring Byrd and Mulock glaciers, and by lateral drag past Minna Bluff, which could have led to a pattern of retreat distinct from other glaciers throughout the Transantarctic Mountains.

A Speleothem Record of Younger Dryas Cooling, Klamath Mountains, Oregon, USA

2005 ◽  
Vol 64 (2) ◽  
pp. 249-256 ◽  
Author(s):  
David A. Vacco ◽  
Peter U. Clark ◽  
Alan C. Mix ◽  
Hai Cheng ◽  
R. Lawrence Edwards
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
Younger Dryas ◽  
Sampling Interval ◽  
Temperature Variability ◽  
Early Holocene ◽  
Last Deglaciation ◽  
Klamath Mountains ◽  
Scale Temperature ◽  
The Last Deglaciation

AbstractA well-dated δ18O record in a stalagmite from a cave in the Klamath Mountains, Oregon, with a sampling interval of 50 yr, indicates that the climate of this region cooled essentially synchronously with Younger Dryas climate change elsewhere in the Northern Hemisphere. The δ18O record also indicates significant century-scale temperature variability during the early Holocene. The δ13C record suggests increasing biomass over the cave through the last deglaciation, with century-scale variability but with little detectable response of vegetation to Younger Dryas cooling.

Long-chain alkenone-inferred temperatures from the last deglaciation to the early Holocene recorded by annually laminated sediments of the maar lake Sihailongwan, northeastern China

The Holocene ◽  
2018 ◽  
Vol 28 (7) ◽  
pp. 1173-1180 ◽  
Author(s):  
Qing Sun ◽  
Guoqiang Chu ◽  
Manman Xie ◽  
Yuan Ling ◽  
Youliang Su ◽  
...  
Keyword(s):  
Temperature Increase ◽  
Growing Season ◽  
Northeastern China ◽  
Early Holocene ◽  
Laminated Sediments ◽  
Last Deglaciation ◽  
Temperature Changes ◽  
Maar Lake ◽  
The Last Deglaciation ◽  
Annually Laminated Sediments

Abrupt temperature changes during the last deglaciation are well recognized in Greenland ice cores and in deep-sea sediment records. On the continent of monsoonal Asia, however, only a few terrestrial temperature reconstructions extend to the Younger Dryas (YD). This hampers the understanding of how the Asian monsoon system responded to large-scale boundary changes in ice-sheet dynamics and reorganizations of atmospheric–oceanic circulation between the last deglaciation and the Holocene. Here, we report an alkenone-inferred temperature record from varved sediments of the maar lake Sihailongwan, northeastern China. Alkenone provides temperatures that represent the water temperature during the growing season when the lake is ice-free. Annually laminated sediments provide a reliable time control. Reconstructed temperatures reveal a distinctive pattern of variations during the last deglaciation: a temperature increase of 6°C at the onset of the Bølling–Allerød, two cold intervals (during the Older Dryas and the intra-Allerød cold period), a relatively minor temperature decrease of 1–3°C during the YD, and a rapid temperature increase of 4–5°C at the early Holocene. The reconstructed temperature records from Lake Sihailongwan and adjacent regions indicate that summer (or growing season) temperature changes were smaller than is evident in Greenland ice core records that are weighted toward winter.

Environmental change in Yellow Sea during the last deglaciation to the early Holocene (15,000–8,000 BP)

2016 ◽  
Vol 392 ◽  
pp. 112-124 ◽  
Author(s):  
Adegoke Olugboyega Badejo ◽  
Bo-Hyung Choi ◽  
Hyen-Goo Cho ◽  
Hi-Il Yi ◽  
Kyung-Hoon Shin
Keyword(s):  
Environmental Change ◽  
Yellow Sea ◽  
Early Holocene ◽  
Last Deglaciation ◽  
The Last Deglaciation
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