Marine evidence for the last glacial advance across eastern Hudson Strait, eastern Canadian Arctic

1998 ◽  
Vol 13 (6) ◽  
pp. 501-514 ◽  
Author(s):  
Anne E. Jennings ◽  
William F. Manley ◽  
Brian Maclean ◽  
John T. Andrews
Keyword(s):  
Canadian Arctic ◽  
Last Glacial ◽  
Eastern Canadian Arctic ◽  
Glacial Advance ◽  
The Last Glacial

scholarly journals Origin of the Phoksundo Tal (lake), Dolpa district, western Nepal

1997 ◽  
Vol 15 ◽  
Author(s):  
H. Yagi
Keyword(s):  
Glacial Retreat ◽  
Last Glacial ◽  
Geomorphic Features ◽  
Glacial Advance ◽  
The Last Glacial

The typical geomorphic features of a landslide such as horseshoe shaped steep scarp and debris mounds are observed adjacent to the southeastern end of the Phoksundo Lake. The mounds consist of rock detritus ranging from cobble size to boulders of several tens of meters in diameter. The total volume of the debris deposited on the left side of the Bauli Gad is estimated to be about l.5 billion m3. The Phoksundo Lake is originated due to landslide damming resulting from a mountain collapse. The detritus is overlying the glacial drift. It implies that one of the glacial valley walls became unstable after the glacial retreat and collapsed over its own glacial drift, probably triggered by an earthquake. The mountain collapse may have occurred around 30 to 40 ka, just after the early substage of the glacial advance in the Last Glacial age.

scholarly journals Southwest Greenland shelf glaciation during MIS 4 more extensive than during the Last Glacial Maximum

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marit-Solveig Seidenkrantz ◽  
Antoon Kuijpers ◽  
Jesper Olsen ◽  
Christof Pearce ◽  
Sofia Lindblom ◽  
...  
Keyword(s):  
Sea Water ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Cycle ◽  
Oxygen Isotope Stage ◽  
Last Glacial ◽  
Irminger Sea ◽  
West Greenland Current ◽  
Glacial Advance ◽  
The Last Glacial

Abstract Although geological and modelling evidence indicate that the last glacial inception in North America was in NE Canada, little is known about the glacial response of the nearby western Greenland Ice Sheet (GIS) during the glacial advance of marine oxygen isotope stage 4 (MIS4). Our multi-proxy study of a marine sediment core collected about 60 km southwest of the Outer Hellefisk Moraines demonstrates that in the southern Davis Strait region the most extreme Greenland shelf glaciation of the last glacial cycle occurred during MIS 4, with another prominent glacial advance at 37–33 kyr BP. During those periods the GIS likely reached the Outer Hellefisk Moraines in this area. Except for these two periods, our data suggest significant advection of relatively warm Irminger Sea Water by the West Greenland Current since MIS 4. This advection likely limited the extent of the MIS2 glaciation on the SW Greenland shelf. Decreased precipitation over southwestern Greenland predicted by atmospheric models as a downstream effect of a much larger MIS2 Laurentide Ice Sheet may have played an additional role.

The Pit House in the Old World and in Native North America

1952 ◽  
Vol 18 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Hiroshi Daifuku
Keyword(s):  
North America ◽  
Western Europe ◽  
Upper Paleolithic ◽  
Old World ◽  
Artificial Structures ◽  
Last Glacial ◽  
Different Types ◽  
Native North America ◽  
Glacial Advance ◽  
The Last Glacial

The problem of the origin and distribution of semi-subterranean structures is an intriguing one. It is generally accepted that the semi-subterranean structure, earth lodge, or pit house, was one of a number of relatively unmodified traits of Old World origin found in North America. This paper reviews some of the literature on the pit house, and summarizes its development and distribution in the Eurasian and North American continents.Laymen, believing that early man habitually lived in caves, commonly use the stereotyped term “cave man” in referring to our early progenitors in the Old World. This assumption was an inevitable development since occupational sites in western Europe are predominantly caves or cave shelters. However, some European archaeologists have suggested such sites were seasonally occupied–that they were the winter habitations of man during the upper Paleolithic. There is reason to believe different types of shelters were used during warm seasons since engravings of tents or more substantial structures (tectiforms) have been found on the walls of caves and cave shelters. A number of European archaeologists including Breuil (1910), Clark (1939), Childe (1950), and others have accepted tectiforms as evidence of the existence of artificial structures in western Europe during the last glacial advance. Breuil has gone further and compared some of the tectiforms in the Font-de-Gaume, the Dordogne Valley of France, to the summer huts of Navahos described by Mendeleff in 1896.

scholarly journals Population structure in Arctic marine forests is shaped by diverse recolonisation pathways and far northern glacial refugia

2020 ◽  
Author(s):  
Trevor T. Bringloe ◽  
Heroen Verbruggen ◽  
Gary W. Saunders
Keyword(s):  
Genetic Diversity ◽  
Last Glacial Maximum ◽  
Bering Sea ◽  
Canadian Arctic ◽  
Species Distributions ◽  
Northwest Atlantic ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Bering Sea ◽  
The Last Glacial

AbstractThe Arctic is experiencing a rapid shift towards warmer regimes, calling for a need to understand levels of biodiversity and ecosystem responses to climate cycles. This study examines marine refugial locations during the Last Glacial Maximum in order to link recolonization pathways to patterns of genetic diversity in Arctic marine forests. We present genetic data for 109 species of seaweed to infer community-level patterns, and hindcast species distributions during the Last Glacial Maximum to further pinpoint likely refugial locations. Sequence data revealed contiguous populations extending from the Bering Sea to the Northwest Atlantic, with high levels of genetic diversity in the East Canadian Arctic. One fifth of the species sampled appeared restricted to Arctic waters. Hindcasted species distributions highlighted refugia in the Bering Sea, Northwest Atlantic, South Greenland, and Europe. We hypothesize that Arctic coastal systems were recolonized from many geographically disparate refugia leading to enriched diversity levels in the East Canadian Arctic, with important contributions stemming from northerly refugia likely centered along Southern Greenland. Moreover, we hypothesize these northerly refugia likely played a key role in promoting polar endemic diversity, as reflected by abundant unique population haplotypes and endemic species in the East Arctic.Significance StatementOur work challenges the existing paradigm that marine Arctic ecosystems are depauperate extensions of southerly (temperate) communities established in the wake of recent glaciation, fundamentally changing how these systems should be viewed and interpreted. We forward novel hypotheses regarding the recent history of Arctic marine systems, particularly with regards to endemism being an integral feature of Arctic biomes, and present a firm framework for future evolutionary research in this system typically viewed as “ecologically immature.”

scholarly journals Glazialtektonik im Weichselglazial Schleswig ­Holsteins und ihre Beziehungen zur Morphologie

1985 ◽  
Vol 34 ◽  
pp. 33-45
Author(s):  
W. Prange
Keyword(s):  
Tectonic Structures ◽  
Ice Flow ◽  
Last Glacial ◽  
Last Glaciation ◽  
The Relationship ◽  
Glacial Advance ◽  
The Last Glacial

Detailed glaciotectonic studies have been conducted in the Weichselian glaciated area of Schleswig-Hol­stein in order to obtain a better understanding about the stratigraphy, the morphogenetic development and thus about the Pleistocene events towards the end of the last glaciation. In general, an upper till discordantly overlies a lower till, which is partly cove'red with meltwater depos­its. The thin upper till cover is probably derived from the last ice readvance in the Oldest Tundra Time, the so-called »Fehmam-advance•, because artifacts found under this till belong to the Younger Hamburg Cul­ture. Various ice tectonic structures such as block-faulted zones, overthrusted folds and folds were observed in these overridden strata. The different directions of the last glacial advance have been determined. The relationship between them and the interpretation of the morphology after Gripp (1952, 1954) is correlated and illustrated with field examples: It is possible to determine the direction of the ice flow from the mor­phology only in regions with strong and definite topography. However, in the gentler rolling regions with weaker and indistinct morphology the overridden strata may either be disturbed or undisturbed without perceptible changes in their palaeorelief. Therefore in these regions, the present day morphology is not the result of the last ice advance alone, but is due to a combination of the penultimate ice advance, the fol­lowing meltwater deposition, the last ice readvance and subsequent melting of dead ice.

scholarly journals Maximum Glacier Extent of the Penultimate Glacial Cycle in the Upper Garonne Basin (Pyrenees): New Chronological Evidence

2021 ◽  
Author(s):  
Marcelo Vieira Fernandes ◽  
Marc Oliva ◽  
Gonçalo Vieira ◽  
David Palacios ◽  
José María Fernández-Fernández ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Mountain Range ◽  
Glacial Cycle ◽  
Terminal Moraine ◽  
Last Glacial ◽  
Exposure Ages ◽  
New Evidence ◽  
Eemian Interglacial ◽  
Glacial Advance ◽  
The Last Glacial

Abstract The Upper Garonne Basin included the longest glacier in the Pyrenees during the Late Pleistocene. During major glacial advances, the Garonne palaeoglacier flowed northwards along ~ 90 km from peaks of the axial Pyrenees exceeding 2,800-3,000 m until the foreland of this mountain range at the Loures-Barouse-Barbazan basin, at only 420–440 m. Here, the palaeoglacier formed a terminal moraine complex that is examined in this work. Based on geomorphological observations and a 12-sample dataset of 10Be Cosmic-Ray Exposure (CRE) ages, we have constrained the timing of the maximum glacial extent as well as the onset of the deglaciation from the end of the Last Glacial Cycle (LGC). Chronological data shows evidence that the external moraines in this basin were abandoned by the ice at the end of the Penultimate Glacial Cycle (PGC) and the onset of the Eemian Interglacial, at ~ 129 ka. No evidence of subsequent glacial advances or standstills occurred during the LGC in this basin were found, as the few existing datable boulders provided in the internal moraine showed inconsistent ages, thus probably being affected by post-glacial processes. The terminal basin was already deglaciated during the global Last Glacial Maximum at 24 − 21 ka, as revealed by exposure ages of polished surfaces at the confluence of the Garonne-La Pique valleys, 13 km south of the entrance of the Loures-Barousse-Barbazan basin. This study introduces the first CRE ages in the Pyrenees for the glacial advance occurred during the PGC and provides also new evidence that glaciers had already significantly shrunk during the LGM.

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.

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