DID THE PACIFIC STORM TRACK REACH NORTHEAST MEXICO DURING THE LAST GLACIAL MAXIMUM?

2020 ◽  
Author(s):  
Kevin Timothy Wright ◽  
◽  
Kathleen R. Johnson ◽  
David McGee ◽  
Gabriela Serrato Marks ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Storm Track ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Pacific ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals Surface geometry of the Last Glacial Maximum (LGM) in the southeastern Swiss Alps (Graubünden) and its paleoclimatological significance

1998 ◽  
Vol 48 (1) ◽  
pp. 23-37 ◽  
Author(s):  
Duri Florineth
Keyword(s):  
Last Glacial Maximum ◽  
Storm Track ◽  
Glacial Maximum ◽  
Swiss Alps ◽  
Geographical Information ◽  
Ice Age ◽  
Surface Geometry ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Using detailed field evidence provided by trimlines on former nunataks, erratic boulders and the orientations of glacial striae, the surface geometry in the accumulation area during the Last Glacial Maximum was reconstructed for the area of SE Switzerland and adjacent Italy. Collectively, the trends of trimline elevations, flowlines deduced from glacial striae and bedrock morphology along the longitudinal valleys and their tributaries indicate that the former accumulation area consisted of an ice dome with the ice divide located over the area enclosed by Schlarignia, Cinuos-chel, Livigno and Piz Bernina. It attained a minimum altitude of approximately 3000 m. Modelling the topography of the ice surface using a Geographical Information System (GIS) is consistent with these results. The paleoclimatological signal included in this surface geometry was used to draw conclusions about the main atmospheric paleocireulation patterns and to outline the principal precipitation areas for the Alps during the last glaciation. It followed from this that ice build-up was principally related to dominating precipitation by southerly circulation (foehn). The prevaleance of foehn circulation most likely reflects a southward shift of the North Atlantic polar atmospheric front and of the accompanied storm track due to the advancing margin of sea ice. There exists good agreement between these assumptions and (a) results of global circulation models for the time of the LGM; (b) estimations of basal shear stress values and flow velocities for Ice Age glaciers; and (c) interpretations of paleowind indicators.

Alpine Evidence for Atmospheric Circulation Patterns in Europe during the Last Glacial Maximum

2000 ◽  
Vol 54 (3) ◽  
pp. 295-308 ◽  
Author(s):  
Duri Florineth ◽  
Christian Schlüchter
Keyword(s):  
Atmospheric Circulation ◽  
Last Glacial Maximum ◽  
Storm Track ◽  
Polar Front ◽  
Glacial Maximum ◽  
Geological Mapping ◽  
Last Glacial ◽  
The Alps ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The configuration of Alpine accumulation areas during the last glacial maximum (LGM) has been reconstructed using glacial–geological mapping. The results indicate that the LGM ice surface consisted of at least three major ice domes, all located south of the principal weather divide of the Alps. This implies that the buildup of the main Alpine ice cover during oxygen isotope stage (OIS) 2 was related to precipitation by dominant southerly atmospheric circulation, in contrast to today's prevalent westerly airflow. Such a reorganization of the atmospheric circulation is consistent with a southward displacement of the Oceanic Polar Front in the North Atlantic and of the associated storm track to the south of the Alps. These results, combined with additional paleoclimate records from western and southern Europe, allow an interpretation of the asynchronous evolution of the different European ice caps during the last glaciation. δ18O stages (OIS) 4 and 3 were characterized by location of the Polar Front north of 46°N (Gulf of Biscay). This affected prevailing westerly circulation and thus, ice buildup in western Scandinavia, the Pyrénées, Vosges, and northern Alps. At the LGM, however, the Polar Front lay at ∼44°N, causing dominating southerly circulation and reduced precipitation in central and northern Europe.

Extensive Early and Middle Wisconsin Glaciation on the Western Olympic Peninsula, Washington, and the Variability of Pacific Moisture Delivery to the Northwestern United States

2001 ◽  
Vol 55 (3) ◽  
pp. 257-270 ◽  
Author(s):  
Glenn D. Thackray
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Organic Detritus ◽  
Last Glacial ◽  
Olympic Mountains ◽  
The Pacific ◽  
Radiocarbon Chronology ◽  
Stratigraphic Sequences ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractLarge glaciers descended western valleys of the Olympic Mountains six times during the last (Wisconsin) glaciation, terminating in the Pacific coastal lowlands. The glaciers constructed extensive landforms and thick stratigraphic sequences, which commonly contain wood and other organic detritus. The organic material, coupled with stratigraphic data, provides a detailed radiocarbon chronology of late Pleistocene ice-margin fluctuations. The early Wisconsin Lyman Rapids advance, which terminated prior to ca. 54,000 14C yr B.P., represented the most extensive ice cover. Subsequent glacier expansions included the Hoh Oxbow 1 advance, which commenced between ca. 42,000 and 35,000 14C yr B.P.; the Hoh Oxbow 2 advance, ca. 30,800 to 26,300 14C yr B.P.; the Hoh Oxbow 3 advance, ca. 22,000–19,300 14C yr B.P.; the Twin Creeks 1 advance, 19,100–18,300 14C yr B.P.; and the subsequent, undated Twin Creeks 2 advance. The Hoh Oxbow 2 advance represents the greatest ice extent of the last 50,000 yr, with the glacier extending 22 km further downvalley than during the Twin Creeks 1 advance, which is correlative with the global last glacial maximum. Local pollen data indicate intensified summer cooling during successive stadial events. Because ice extent was diminished during colder stadial events, precipitation—not summer temperature—influenced the magnitude of glaciation most strongly. Regional aridity, independently documented by extensive pollen evidence, limited ice extent during the last glacial maximum. The timing of glacier advances suggests causal links with North Atlantic Bond cycles and Heinrich events.

scholarly journals North Atlantic storm track changes during the Last Glacial Maximum recorded by Alpine speleothems

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Marc Luetscher ◽  
R. Boch ◽  
H. Sodemann ◽  
C. Spötl ◽  
H. Cheng ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
North Atlantic ◽  
Storm Track ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

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.

Sign in / Sign up

Export Citation Format

Share Document