scholarly journals Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radiocarbon Dates from Bluefish Caves, Canada

PLoS ONE ◽  
2017 ◽  
Vol 12 (1) ◽  
pp. e0169486 ◽  
Author(s):  
Lauriane Bourgeon ◽  
Ariane Burke ◽  
Thomas Higham
1998 ◽  
Vol 49 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Marie-Pierre Ledru ◽  
Jacques Bertaux ◽  
Abdelfettah Sifeddine ◽  
Kenitiro Suguio

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.


Science ◽  
2021 ◽  
Vol 373 (6562) ◽  
pp. 1528-1531 ◽  
Author(s):  
Matthew R. Bennett ◽  
David Bustos ◽  
Jeffrey S. Pigati ◽  
Kathleen B. Springer ◽  
Thomas M. Urban ◽  
...  

2020 ◽  
Vol 16 (1) ◽  
pp. 199-209 ◽  
Author(s):  
Yongyun Hu ◽  
Yan Xia ◽  
Zhengyu Liu ◽  
Yuchen Wang ◽  
Zhengyao Lu ◽  
...  

Abstract. The Pacific–North American (PNA) teleconnection is one of the most important climate modes in the present climate condition, and it enables climate variations in the tropical Pacific to exert a significant influence on North America. Here, we show climate simulations in which the PNA teleconnection was largely distorted or broken at the Last Glacial Maximum (LGM). The distorted PNA is caused by a split in the westerly jet stream, which is ultimately forced by the large, thick Laurentide ice sheet that was present at the LGM. Changes in the jet stream greatly alter the extratropical waveguide, distorting wave propagation from the North Pacific to North America. The distorted PNA suggests that climate variability in the tropical Pacific, notably El Niño–Southern Oscillation (ENSO), would have little direct impact on North American climate at the LGM.


2015 ◽  
Vol 8 (3) ◽  
pp. 201-205 ◽  
Author(s):  
Jessica L. Oster ◽  
Daniel E. Ibarra ◽  
Matthew J. Winnick ◽  
Katharine Maher

2021 ◽  
Author(s):  
Karen Søby Özdemir ◽  
Henrieka Detlef ◽  
Linda Lambertucci ◽  
Christof Pearce

<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>


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