Late Holocene beetle assemblages and environmental change in Gammelhemmet, northern Sweden

Boreas ◽  
2014 ◽  
Vol 44 (2) ◽  
pp. 368-382 ◽  
Author(s):  
Sara Khorasani ◽  
Eva Panagiotakopulu ◽  
Roger Engelmark ◽  
Ian Ralston
Keyword(s):  
Environmental Change ◽  
Late Holocene ◽  
Northern Sweden ◽  
Beetle Assemblages

Holocene dune activity and environmental change in the prairie parki and and boreal forest, central Saskatchewan, Canada

The Holocene ◽  
2006 ◽  
Vol 16 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Stephen A. Wolfe ◽  
Jeff Ollerhead ◽  
David J. Huntley ◽  
Olav B. Lian
Keyword(s):  
Environmental Change ◽  
Boreal Forest ◽  
Great Plains ◽  
Late Holocene ◽  
Early Holocene ◽  
Aeolian Activity ◽  
Landscape Response ◽  
Response To Environmental Change ◽  
Holocene Activity ◽  
Dune Activity

Past aeolian activity was reconstructed at four dunefields in the prairie parkland and boreal forest of central Saskatchewan to elucidate landscape response to environmental change. Optical ages from stabilized dunes in the boreal transition ecoregion indicate two episodes of activity. The first, at about 11 ka, corresponds to a period of early-Holocene parkland and grassland cover following deglaciation and drainage after about 13.0 ka, and brief establishment of boreal forest. The second, between about 7.5 and 5 ka, corresponds to a period of mid-Holocene parkland-grassland cover. Optical ages from dunefields in the prairie parkland primarily record mid-Holocene activity, between about 7.5 and 4.7 ka, corresponding to a period of grassland cover, with some reworking continuing into the late Holocene. Although this area was deglaciated by about 13.5 ka, there is no evidence of early-Holocene dune activity, suggesting that mid-Holocene activity may have reworked earlier deposits here. Consequently, much of the morphology and stratigraphy observed in these dunefields are associated with mid-Holocene activity, likely associated with increased aridity and reduced vegetation cover at that time. This study provides the most northerly evidence of mid-Holocene dune reactivation on the Great Plains, lending support to the assertion that aeolian activity was widespread at that time.

Geochemical time series from lake sediments of the Central Asia as chronologic evidence of environmental change over the Late Holocene

2006 ◽  
Vol 25 (S1) ◽  
pp. 6-6
Author(s):  
Andrey V. Daryin ◽  
Ivan A. Kalugin ◽  
Lubov G. Smolyaninova ◽  
Konstantin V. Zolotarev ◽  
Elena G. Vologina ◽  
...  
Keyword(s):  
Time Series ◽  
Environmental Change ◽  
Central Asia ◽  
Lake Sediments ◽  
Late Holocene

Late Holocene glacier and climate reconstruction from proglacial records in Vatnsdalur, northern Iceland.

2020 ◽  
Author(s):  
Konstantin Nebel ◽  
Timothy Lane ◽  
Kathryn Adamson ◽  
Iestyn Barr ◽  
Willem van der Bilt ◽  
...  
Keyword(s):  
High Resolution ◽  
Environmental Change ◽  
North Atlantic ◽  
Late Holocene ◽  
Sediment Cores ◽  
Arctic Region ◽  
Arctic Climate ◽  
The Arctic ◽  
Air Masses ◽  
Proglacial Lake

<p>The Arctic region is experiencing surface air temperature increase of twice the global average. To better understand Holocene Arctic climate variability, there is the need for continuous, high-resolution palaeoclimate archives. Sediment cores from proglacial lakes can provide such climate archives, and have the potential to record past environmental change in detail.       </p><p>Vatnsdalur, a valley in northern Iceland, hosts small, climatically sensitive cirque glaciers that became independent from the Iceland Ice Sheet after its retreat following the Last Glacial Maximum (c. 15 ka BP). Importantly, this region is located at the confluence of warm water and air masses from the south and cold polar water and air masses from the north, making it highly sensitive to North Atlantic and Arctic climate change. However, at present the region is highly understudied, lacking any high-resolution climate reconstructions.           </p><p>To address this, we combine geomorphological mapping with the first high-resolution analysis of proglacial lake sediments, to thoroughly examine northern Iceland Late Holocene environmental change.</p><p>Field mapping supplemented by high-resolution drone data was used to characterise catchment geomorphology, including seven Holocene moraines. A sediment core (SKD-P1-18) from proglacial lake Skeiðsvatn, Vatnsdalur, was analysed for sedimentological (dry bulk density, loss-on-ignition, grain size), geophysical (magnetic susceptibility) and geochemical (X-ray fluorescence core scan, 2 mm resolution) parameters.             <br>We identify three main sedimentary facies from these analyses, indicating variations in glacial input and catchment environmental conditions. Radiocarbon dating of lake macrofossils, supplemented by tephrochronology, provides a chronological framework. Catchment point samples, also analysed using the above analytical techniques, were used for sediment fingerprinting to disentangle non-glacial from glacial end-members.</p><p>Our results indicate the disappearance and reformation of small, climatically sensitive cirque glaciers in Vatnsdalur during the Holocene. We interpret the data to show an abrupt return to a glaciated catchment. Our results fill a geographical gap of high-resolution proglacial sediment studies in the Arctic-North Atlantic region.</p>

Holocene Environmental Change, Artiodactyl Abundances, and Human Hunting Strategies in the Great Basin

2004 ◽  
Vol 69 (2) ◽  
pp. 235-255 ◽  
Author(s):  
David A. Byers ◽  
Jack M. Broughton
Keyword(s):  
Environmental Change ◽  
Great Basin ◽  
Late Holocene ◽  
Coarse Grained ◽  
Population Increase ◽  
Hunting Behavior ◽  
Fine Grained ◽  
Hunting Strategies ◽  
Bonneville Basin ◽  
Holocene Environmental Change

Despite a deep Great Basin tradition of incorporating paleoenvironmental change within ecologically oriented analyses of past human lifeways, there has been little attention focused on Holocene variation in artiodactyl abundances and the human hunting strategies dependent upon them. Here, we draw upon recently generated paleontological evidence from Homestead Cave of the Bonneville Basin to document a late Holocene artiodactyl population increase. We then use the prey model of foraging theory to predict late Holocene increases in the hunting of artiodactyls, relative to lagomorphs. That prediction is then tested against several fine-grained archaeological records of hunting behavior in the Bonneville Basin, Hogup Cave and Camels Back Cave, and a variety of more coarse-grained faunal records from throughout the Great Basin. Close fits are found between the deductively derived prediction and the empirical records of hunting behavior: dramatic proportional increases in artiodactyl hunting occurred during the late Holocene. The results have far-reaching implications for our understanding of prehistoric human adaptations in the Great Basin.

Late Holocene environmental change in the Howgill Fells, Northwest England

Geomorphology ◽  
2008 ◽  
Vol 100 (1-2) ◽  
pp. 41-69 ◽  
Author(s):  
R.C. Chiverrell ◽  
A.M. Harvey ◽  
S.Y. Hunter (née Miller) ◽  
J. Millington ◽  
N.J. Richardson
Keyword(s):  
Environmental Change ◽  
Late Holocene ◽  
Holocene Environmental Change

Holocene environmental change resets lichen surface dates on Recess Peak glacial deposits in the Sierra Nevada, California

2013 ◽  
Vol 80 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Louis A. Scuderi ◽  
Peter J. Fawcett
Keyword(s):  
Climate Change ◽  
Environmental Change ◽  
Sierra Nevada ◽  
Radiocarbon Dating ◽  
Late Holocene ◽  
Tree Line ◽  
Glacial Deposits ◽  
Present Evidence ◽  
Holocene Environmental Change ◽  
Age Estimates

Development of an accurate chronology for glacial deposits in the Sierra Nevada has long been problematic given the lack of suitable organic material for radiocarbon dating. Lichenometry initially appeared promising as ages showed an increase from cirque headwalls to down-canyon moraines. However, while Recess Peak lichen age estimates range from 2 to 3 ka, recent work shows these deposits to be at least 10 ka older. Here, we present evidence for a late Holocene reset of Recess Peak lichen ages by significant post-depositional climate change. Following late-Pleistocene deposition of Recess Peak moraines, warming through the mid-Holocene allowed forests to advance into shallow basins eliminating local inverted tree lines. This produced a partial canopy where shading killed the original post-Pleistocene crustose lichen colonies. Late-Holocene cooling resulted in forest retreat from these basins as alpine tree line fell. Lichens then recolonized the re-exposed Recess Peak deposits. We conclude that while Recess Peak lichen ages are accurate to within the dating uncertainty of the technique, existing lichen ages actually date the timing of post-mid-Holocene cooling and recolonization, and not the original emplacement of these deposits. Thus, applications of Lichenometry should consider post-depositional environmental change when interpreting the meaning of these dates.

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