Presence of cave bears in western Austria before the onset of the Last Glacial Maximum: new radiocarbon dates and palaeoclimatic considerations

2014 ◽  
Vol 29 (8) ◽  
pp. 760-766 ◽  
Author(s):  
CHRISTOPH SPÖTL ◽  
PAULA J. REIMER ◽  
GERNOT RABEDER ◽  
DENIS SCHOLZ
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Absence of Last Glacial Maximum Records in Lowland Tropical Forests

1998 ◽  
Vol 49 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Marie-Pierre Ledru ◽  
Jacques Bertaux ◽  
Abdelfettah Sifeddine ◽  
Kenitiro Suguio
Keyword(s):  
South America ◽  
Tropical Forests ◽  
Last Glacial Maximum ◽  
Sedimentation Rate ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
Pollen Records ◽  
The Last Glacial

Environmental conditions of the lowland tropical forests during the last glacial maximum (LGM) between ca 20,000 and 18,000 14C yr B.P., are reevaluated in terms of dating control and lithology analyzed in seven pollen records from South America. The reevaluation shows that probably in none of the published records are LGM sediments present or abundant. This conclusion is based on the occurrence of abrupt lithologic changes coupled with changes in sedimentation rate interpolated from radiocarbon dates. These findings suggest that the LGM was represented probably by a hiatus of several thousand years, indicative of drier climates than before or after.

The Last Glacial Maximum in northern Baffin Bay

2021 ◽  
Author(s):  
Karen Søby Özdemir ◽  
Henrieka Detlef ◽  
Linda Lambertucci ◽  
Christof Pearce
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Ice Shelf ◽  
Radiocarbon Dates ◽  
The Holocene ◽  
Baffin Bay ◽  
Last Glacial ◽  
The Core ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Little is known about climate and ocean conditions during the Last Glacial Maximum in Baffin Bay, Greenland. This is partly due to the dissolution of biogenic carbonates in the central Baffin Bay, preventing reliable <sup>14</sup>C-chronologies. We present the results from a transect of gravity cores retrieved during the 2019 BIOS cruise on the HDMS Lauge Koch in the northern Baffin Bay. Core LK19-ST8-14G has been analyzed for grain size variations, sea-ice biomarkers, XRF, and color spectrophotometry. A preliminary chronology based on radiocarbon dates from foraminifera show that the bottom of the core is approximately 35.000 cal. years BP while the top sediments are of Late Holocene age. The sediment archive thus covers the full extent of the LGM and the last deglaciation. High-resolution photography and CT scans allowed the identification of distinctly different lithofacies in the sediment archive. The lower sections of the core are characterized by laminated mud with no IRD and absence of microfossils indicating a sub ice-shelf environment during the glacial period. The laminated sequence is interrupted by several coarser, detrital-carbonate (DC) rich layers which are interpreted as episodes of glacial retreat or ice-shelf collapse. The youngest of these DC layers immediately precedes the Holocene, which is represented by approximately 40 cm of bioturbated sediments with some IRD. This interpretation is supported by the concentrations of HBIs and sterols throughout the core, which indicate near perennial ice cover in the glacial northern Baffin Bay and more open water conditions during the Holocene.</p>

Sediment record of precipitation and changes in circulation in Bohol Sea area since the Last Glacial Maximum

2020 ◽  
Author(s):  
Sarahmae Buen ◽  
Fernando Siringan ◽  
Ronald Lloren
Keyword(s):  
Sea Level ◽  
Last Glacial Maximum ◽  
Accumulation Rate ◽  
The Philippines ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
Sediment Input ◽  
The Last Glacial Maximum ◽  
The Last Glacial

<p>Deep marine sediments may provide insights of past climate and oceanographic events. Knowledge of the past events can aid in scenario setting of future climate and their oceanographic consequences. A deep sea sediment core from the western side of Bohol Sea, a marginal sea located south of the Philippines, was used to reconstruct precipitation and identify the impacts of sea level rise on the circulation of Bohol Sea.  Five radiocarbon dates from bulk organic matter provide age control spanning back to the Last Glacial Maximum. Sedimentological (lithics and carbonate fractions; bulk density; sedimentation rate and mass accumulation rate) and geochemical (Ti, Al, Zr, Ti/Al and Y/Ni) data were used to reconstruct the sediment input for the area. Sediment input was decreasing from 20-15ka, followed by a relatively stable trend until ~9ka. After ~9ka sediment input increased up until the most recent years. Sedimentation trend follows the average winter (DJF) insolation curve at 10<sup>o</sup>N. This signifies that the sediment input reflects the general changes in precipitation in the area. Lithics and carbonate contents reflect a shift in sediment source that could be attributed to the change in circulation in the basin as the sea level rose to overtop the Surigao Strait located at the northeastern side of the basin. Greater westward transport of suspended material from large rivers to the east would contribute to the sedimentation in the western part of Bohol Sea.</p>

Extent and Timing of the Last Glacial Maximum in Southwestern Alaska

1994 ◽  
Vol 42 (2) ◽  
pp. 136-148 ◽  
Author(s):  
Daniel H. Mann ◽  
Dorothy M. Peteet
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Lower Latitude ◽  
Radiocarbon Dates ◽  
Alaska Peninsula ◽  
Last Glacial ◽  
Kodiak Island ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Southwestern Alaska

AbstractA glacier complex composed of confluent alpine glaciers, island ice caps, and piedmont lobes covered much of the Alaska Peninsula and Kodiak Island during the last glacial maximum (LGM). Because this glacier complex formed the southeastern border of Beringia, its dynamics may have been important in the timing and feasibility of the northwest coast route for human migration into lower-latitude North America. Radiocarbon dates from stratigraphic sections on Kodiak Island and in the Bristol Bay lowlands bracket the LGM in southwestern Alaska between 23,000 and 14,700 yr B.P. Reconstruction of ice thickness based on glacier trimlines, moraines, and calculations of basal-shear stress depict the Alaska Peninsula Glacier Complex flowing to the outer edge of the continental shelf in the Gulf of Alaska. Equilibrium-line altitudes (ELAs) were 300 to 700 m lower than today and approached sea level on the southwestern Alaska Peninsula. In northeastern areas where ELAs were higher, bedrock topography largely controlled ice flow except where ice saddles bridged straits and inlets.

Implications of a Bayesian radiocarbon calibration of colonization ages for mammalian megafauna in glaciated New York State after the Last Glacial Maximum

2016 ◽  
Vol 85 (2) ◽  
pp. 262-270 ◽  
Author(s):  
Robert S. Feranec ◽  
Andrew L. Kozlowski
Keyword(s):  
New York ◽  
Last Glacial Maximum ◽  
New York State ◽  
The State ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
York State ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

To understand what factors control species colonization and extirpation within specific paleoecosystems, we analyzed radiocarbon dates of megafaunal mammal species from New York State after the Last Glacial Maximum. We hypothesized that the timing of colonization and extirpation were both driven by access to preferred habitat types. Bayesian calibration of a database of 39 radiocarbon dates shows that caribou (Rangifer tarandus) were the first colonizers, then mammoth (Mammuthus sp.), and finally American mastodon (Mammut americanum). The timing of colonization cannot reject the hypothesis that colonizing megafauna tracked preferred habitats, as caribou and mammoth arrived when tundra was present, while mastodon arrived after boreal forest was prominent in the state. The timing of caribou colonization implies that ecosystems were developed in the state prior to 16,000 cal yr BP. The contemporaneous arrival of American mastodon with Sporormiella spore decline suggests the dung fungus spore is not an adequate indicator of American mastodon population size. The pattern in the timing of extirpation is opposite to that of colonization. The lack of environmental changes suspected to be ecologically detrimental to American mastodon and mammoth coupled with the arrival of humans shortly before extirpation suggests an anthropogenic cause in the loss of the analyzed species.

scholarly journals Timing and position of Late Wisconsinan ice-margins on the upper slope seaward of Laurentian Channel

2004 ◽  
Vol 55 (2) ◽  
pp. 131-140 ◽  
Author(s):  
David J. W. Piper ◽  
Adam Macdonald
Keyword(s):  
Continental Slope ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Grand Banks ◽  
Last Glacial ◽  
Seismic Reflection Profiles ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Upper Slope

Abstract At the last glacial maximum, the major ice outlet through Laurentian Channel terminated on the upper continental slope. A 10 km square area of the upper slope has been investigated in detail, using airgun and boomer seismic reflection profiles and piston cores. Sediment failure during the 1929 Grand Banks earthquake resulted in exposure at the seabed of Last Glacial Maximum sediments that are normally buried beneath tens of metres of younger strata. Ice-margin acoustic and lithofacies are interpreted using criteria developed on the continental shelf and chronology is provided by AMS radiocarbon dates on in situ mollusc shells. Seismic data show a morainal ridge at 500 mbsl (mbsl = metres below (present) sea level) corresponding to the Last Glacial Maximum ice grounding line. A change in thermal regime of the ice or a subglacial meltwater outburst, at 16.5 ± 0.15 ka (radiocarbon years, -0.4 ka marine reservoir correction applied), resulted in release of sediment-laden meltwater that eroded gullies on the continental slope. This erosion surface is immediately overlain by a prominent stony diamict that extends to about 700 mbsl and may represent till deposition from a glacial surge. The ice margin then retreated upslope by 16.3 ka, probably to the prominent moraine at 380 mbsl at the lip of the Laurentian Channel. Evidence from mud turbidites on Laurentian Fan suggests that this ice marginal position may have persisted until about 14.2 ka. Ice then retreated rapidly northwards up Laurentian Channel, synchronous with Heinrich Event 1 at about 14 ka. Younger proglacial sediment on the upper continental slope slumped at about 12 ka, probably as a result of loading by a late-ice advance across St. Pierre Bank.

scholarly journals Radiocarbon Dates from the Pleistocene Fossil Deposits of Samwel Cave, Shasta County, California, USA

Radiocarbon ◽  
2007 ◽  
Vol 49 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Robert S Feranec ◽  
Elizabeth A Hadly ◽  
Jessica L Blois ◽  
Anthony D Barnosky ◽  
Adina Paytan
Keyword(s):  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Glacial Maximum ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
Cave Deposits ◽  
Shasta County ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Dates obtained from the collagen of 5 mammals from the fossil deposits of Samwel Cave, Shasta County, California, USA, show emplacement during the last glacial maximum. These dates support the assignment of the fauna to the late Pleistocene. The Samwel Cave deposits currently do not appear to be stratified.

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