scholarly journals Palaeoecological and palaeoclimatic conditions on the Karelian Isthmus (northwestern Russia) during the Holocene

2020 ◽  
Vol 95 ◽  
pp. 65-83 ◽  
Author(s):  
Larisa Nazarova ◽  
Liudmila S. Syrykh ◽  
Roseanna J. Mayfield ◽  
Larisa A. Frolova ◽  
Aisylu G. Ibragimova ◽  
...  
Keyword(s):  
Early Holocene ◽  
Karelian Isthmus ◽  
Holocene Climate ◽  
The West ◽  
The Holocene ◽  
Pleistocene Climate ◽  
Breakpoint Analysis ◽  
Corynocera Ambigua ◽  
July Temperature ◽  
Northwestern Russia

AbstractThe Holocene evolution of climate in easternmost Fennoscandia and adjoining regions is poorly known, compared with regions to the west. To address this, a 224-cm-long sediment core from Lake Medvedevskoe, situated on the Central Upland of the Karelian Isthmus, northwestern Russia, was examined to investigate variations in the Holocene climate. Analyses indicate that the dry and cold late Pleistocene climate was replaced by the warmer and more humid early Holocene climate after ca. 10.5 cal ka BP. During the early Holocene, the lake transitioned from an oligotrophic to a mesotrophic state, characterized by a “Corynocera ambigua/Microtendipes pedellus-type” phase, which has been found in other lakes across Fennoscandia. Taxonomic shifts in the chironomid and cladoceran communities associated with climatic amelioration were identified at ca. 10.6 and 9.17 cal ka BP using breakpoint analysis. Reconstructed July temperatures indicate climatic patterns comparable to those seen in eastern Fennoscandia. The warm period between ca. 9.5 and 5.5 cal ka BP (T July 14.5–15°C) was interrupted by a slight cooling between ca. 8.5 and 8.1 cal ka BP, possibly relating to the 8.2 event, with peak temperature reached at ca. 7.8 cal ka BP. Neoglacial cooling started after ca. 5.5 cal ka BP, the median reconstructed July temperature dropped to 2–3°C cooler than present (mean T July 13.5°C) before recovering in recent time.

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

2013 ◽  
Vol 9 (4) ◽  
pp. 1629-1643 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene thermal maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveals a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from the previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in an ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of the early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere-sea ice-ocean model

2012 ◽  
Vol 8 (5) ◽  
pp. 5263-5291 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene Thermal Maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveal a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from a previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in a ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that the modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

Stability of Holocene Climate Regimes in the Yellowstone Region

1995 ◽  
Vol 43 (3) ◽  
pp. 433-436 ◽  
Author(s):  
Cathy Whitlock ◽  
Patrick J. Bartlein ◽  
Kelli J. Van Norman
Keyword(s):  
Early Holocene ◽  
Summer Drought ◽  
Pollen Record ◽  
Holocene Climate ◽  
Pressure System ◽  
Climate History ◽  
The Holocene ◽  
Mountainous Regions ◽  
History Of ◽  
Wet Climate

AbstractA 12,500-yr pollen record from Loon Lake, Wyoming provides information on the climate history of the southwestern margin of Yellowstone National Park. The environmental reconstruction was used to evaluate hypotheses that address spatial variations in the Holocene climate of mountainous regions. Loon Lake lies within the summer-dry/winter-wet climate regime. An increase in xerophytic pollen taxa suggests drier-than-present conditions between ca. 9500 and 5500 14C yr B.P. This response is consistent with the hypothesis that increased summer radiation and the expansion of the east Pacific subtropical high-pressure system in the early Holocene intensified summer drought at locations within the summer-dry/winter-wet regime. This climate history contrasts with that of nearby sites in the summer-wet/winter-dry region, which were under the influence of stronger summer monsoonal circulation in the early Holocene. The Loon Lake record implies that the location of contrasting climate regimes did not change in the Yellowstone region during the Holocene. The amplitude of the regimes, however, was determined by the intensity of circulation features and these varied with temporal changes in the seasonal distribution of solar radiation.

Abrupt cooling repeatedly punctuated early-Holocene climate in eastern North America

The Holocene ◽  
2011 ◽  
Vol 22 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Juzhi Hou ◽  
Yongsong Huang ◽  
Bryan N Shuman ◽  
W Wyatt Oswald ◽  
David R Foster
Keyword(s):  
North America ◽  
Early Holocene ◽  
Eastern North America ◽  
Holocene Climate

Small-mammal diversity in Spain during the late Pleistocene to early Holocene: Climate, landscape, and human impact

Geology ◽  
2012 ◽  
Vol 41 (2) ◽  
pp. 267-270 ◽  
Author(s):  
J. M. Lopez-Garcia ◽  
H.-A. Blain ◽  
J. I. Morales ◽  
C. Lorenzo ◽  
S. Banuls-Cardona ◽  
...  
Keyword(s):  
Human Impact ◽  
Late Pleistocene ◽  
Small Mammal ◽  
Early Holocene ◽  
Holocene Climate ◽  
Mammal Diversity

The dynamics of Holocene monsoon based on meteoric 10Be at Kunlun Pass on the northeastern Qinghai-Tibet Plateau

2021 ◽  
Author(s):  
Peng Chen ◽  
Zhongbo Yu ◽  
Markus Czymzik ◽  
Ala Aldahan ◽  
Jinguo Wang ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Early Holocene ◽  
Tibet Plateau ◽  
The Holocene ◽  
Proxy Records ◽  
Low Levels ◽  
High Level ◽  
Qinghai Tibet Plateau

<p>Multiple proxy records have been used for the understanding of environmental and climate changes during the Holocene. For the first time, we here measure meteoric <sup>10</sup>Be isotope of sediments from a drill core collected at the Kunlun Pass (KP) on the northeastern Qinghai-Tibet Plateau (NETP) to investigate mositure and atmospheric circulation changes during the Holocene. The <sup>10</sup>Be flux suggests relative low levels in the Early Holocene, followed by a sharp increase to high values at around 4 ka BP (4 ka BP = 4000 years before present). Afterwards, the <sup>10</sup>Be flux remains on a high level during the Late Holocene, but decreases slightly towards today. These <sup>10</sup>Be deposition patterns are compared to moisture changes in regions dominated by the Indian Summer Monsoon (ISM), East Asian Summer Monsoon (EASM), and the Westerlies. Different from the gradual changes in monsoon patterns, the <sup>10</sup>Be data reveal low levels during the Early Holocene until ~4 ka BP when an obvious increase was indicated and a relative high level continues to this day, which is relatively more in agreement with patterns of the Westerlies. This finding provides a new evidence for a shift in the dominant pattern of atmospheric circulation at the KP region from a more monsoonal one to one dominated by the Westerlies. Our results improve the understanding of non-stationary interactions and spatial relevance of the EASM, the ISM and the Westerlies on the Qinghai-Tibet Plateau.</p>

A radiocarbon chronology of Holocene climate change and sea-level rise at the Delmarva Peninsula, US Mid-Atlantic Coast

The Holocene ◽  
2021 ◽  
pp. 095968362110482
Author(s):  
Kelvin W Ramsey ◽  
Jaime L. Tomlinson ◽  
C. Robin Mattheus
Keyword(s):  
Climate Change ◽  
North America ◽  
Sea Level Rise ◽  
Sea Level ◽  
Early Holocene ◽  
Eastern North America ◽  
Delmarva Peninsula ◽  
The Holocene ◽  
Cool Climate ◽  
And Sea Level

Radiocarbon dates from 176 sites along the Delmarva Peninsula record the timing of deposition and sea-level rise, and non-marine wetland deposition. The dates provide confirmation of the boundaries of the Holocene subepochs (e.g. “early-middle-late” of Walker et al.) in the mid-Atlantic of eastern North America. These data record initial sea-level rise in the early Holocene, followed by a high rate of rise at the transition to the middle Holocene at 8.2 ka, and a leveling off and decrease in the late-Holocene. The dates, coupled to local and regional climate (pollen) records and fluvial activity, allow regional subdivision of the Holocene into six depositional and climate phases. Phase A (>10 ka) is the end of periglacial activity and transition of cold/cool climate to a warmer early Holocene. Phase B (10.2–8.2 ka) records rise of sea level in the region, a transition to Pinus-dominated forest, and decreased non-marine deposition on the uplands. Phase C (8.2–5.6 ka) shows rapid rates of sea-level rise, expansion of estuaries, and a decrease in non-marine deposition with cool and dry climate. Phase D (5.6–4.2 ka) is a time of high rates of sea-level rise, expanding estuaries, and dry and cool climate; the Atlantic shoreline transgressed rapidly and there was little to no deposition on the uplands. Phase E (4.2–1.1 ka) is a time of lowering sea-level rise rates, Atlantic shorelines nearing their present position, and marine shoal deposition; widespread non-marine deposition resumed with a wetter and warmer climate. Phase F (1.1 ka-present) incorporates the Medieval Climate Anomaly and European settlement on the Delmarva Peninsula. Chronology of depositional phases and coastal changes related to sea-level rise is useful for archeological studies of human occupation in relation to climate change in eastern North America, and provides an important dataset for future regional and global sea-level reconstructions.

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