scholarly journals Changes in the Western Boundary Undercurrent Outflow since the Last Glacial Maximum, from smectite/illite ratios in deep Labrador Sea sediments

1997 ◽  
Vol 12 (1) ◽  
pp. 79-96 ◽  
Author(s):  
Nathalie Fagel ◽  
Claude Hillaire-Marcel ◽  
Christian Robert
1999 ◽  
Vol 14 (6) ◽  
pp. 777-788 ◽  
Author(s):  
Nathalie Fagel ◽  
Christophe Innocent ◽  
Ross K. Stevenson ◽  
Claude Hillaire-Marcel

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marit-Solveig Seidenkrantz ◽  
Antoon Kuijpers ◽  
Steffen Aagaard-Sørensen ◽  
Holger Lindgreen ◽  
Jesper Olsen ◽  
...  

AbstractThe Last Glacial Maximum (LGM, 23–19,000 year BP) designates a period of extensive glacial extent and very cold conditions on the Northern Hemisphere. The strength of ocean circulation during this period has been highly debated. Based on investigations of two marine sediment cores from the Davis Strait (1033 m water depth) and the northern Labrador Sea (2381 m), we demonstrate a significant influx of Atlantic-sourced water at both subsurface and intermediate depths during the LGM. Although surface-water conditions were cold and sea-ice loaded, the lower strata of the (proto) West Greenland Current carried a significant Atlantic (Irminger Sea-derived) Water signal, while at the deeper site the sea floor was swept by a water mass comparable with present Northeast Atlantic Deep Water. The persistent influx of these Atlantic-sourced waters entrained by boundary currents off SW Greenland demonstrates an active Atlantic Meridional Overturning Circulation during the LGM. Immediately after the LGM, deglaciation was characterized by a prominent deep-water ventilation event and potentially Labrador Sea Water formation, presumably related to brine formation and/or hyperpycnal meltwater flows. This was followed by a major re-arrangement of deep-water masses most likely linked to increased overflow at the Greenland-Scotland Ridge after ca 15 kyr BP.


Author(s):  
Nicole R. Marshall ◽  
Anne de Vernal ◽  
Alfonso Mucci ◽  
Alexandra Filippova ◽  
Markus Kienast ◽  
...  

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.


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