Late Quaternary glacial history and meltwater discharges along the Northeastern Newfoundland Shelf

2013 ◽  
Vol 50 (12) ◽  
pp. 1178-1194 ◽  
Author(s):  
Jonathan Roger ◽  
Francky Saint-Ange ◽  
Patrick Lajeunesse ◽  
Mathieu J. Duchesne ◽  
Guillaume St-Onge
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Water Environment ◽  
Open Water ◽  
Laurentide Ice Sheet ◽  
Glacial Processes ◽  
Trough Mouth Fans ◽  
Seismic Reflection Profiles ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The geomorphology of the Eastern Canadian margin has been shaped by glacial processes during the Quaternary. Many studies have focused on the ice-sediment pathway through Hudson Strait to reconstruct the dynamics of the Laurentide Ice Sheet, and as a consequence, little is known on its marginal ice domes. Here we reconstruct the dynamics of two trough mouth fans (TMFs) offshore NE Newfoundland using sediment cores and radiocarbon ages supported by very high resolution seismic reflection profiles. These two TMFs, namely Notre Dame and Hawke, are fed by two glacial troughs incised in the bedrock. The TMFs show a complete sedimentary sequence from 30 ka BP to the beginning of the Holocene. The sampled sedimentary record on the upper slope extends back to a thick Heinrich event 3 (H3) deposit that corresponds to the end of the maximum extent of the Newfoundland ice dome. Above H3, a thick succession of turbidite deposits (>10 m) observed in both TMFs is correlated with periods of major meltwater supply from 28–29 to 17 ka BP. Our results show that the Last Glacial Maximum (LGM) period was characterized by major input of meltwater events stemming from the Newfoundland dome. The presence of H1 (∼17 ka BP) coincide with the end of the turbidite activity which is replaced by an open-water environment characterized by hemipelagic sediments rich in ice-rafted debris. The proglacial muddy sediment older than 13.3 ka BP on the shelf shows that ice was not grounded after H1, suggesting a very rapid retreat of the ice on the Newfoundland shelf after 17 ka BP.

Late Quaternary sedimentation on the southwestern Scotian Slope, eastern Canada: relationship to glaciationGeological Survey of Canada Contribution 20070176.

2008 ◽  
Vol 45 (3) ◽  
pp. 267-285 ◽  
Author(s):  
Thian Hundert ◽  
David J.W. Piper
Keyword(s):  
Late Quaternary ◽  
Sediment Cores ◽  
Sediment Supply ◽  
Scotian Shelf ◽  
Eastern Canada ◽  
Glacial Retreat ◽  
Air Gun ◽  
Continental Slopes ◽  
History Of ◽  
Seismic Reflection Profiles

The sedimentary record on continental slopes has the potential to preserve a record of glacial retreat on the adjacent continental shelf. The glacial history of the southwestern part of the Scotian Shelf is poorly known. Air-gun and high-resolution sparker profiles and numerous sediment cores up to 10 m long have been used to determine the character of sedimentation on the southwestern Scotian Slope since the last glacial maximum (LGM). Seismic-reflection profiles show that glacial till was deposited at shallow depths on the upper continental slope, and correlation to dated piston cores farther downslope show that this till dates from the LGM. Slope sedimentation at this time was dominated by local ice and deposited as plume fallout and turbidites. Progressively increasing importance of red-brown sediment derived from glacial supply to Laurentian Channel indicates retreat of ice from the shelf edge and diminishing supply of proglacial sediment from the calving embayment in the mid-Scotian Shelf. With the termination of distal proglacial sediment supply, the sedimentation rate diminished rapidly and hemipelagic sedimentation prevailed through the Holocene.

scholarly journals Sea level implications from Late Quaternary/Holocene paleosols from the Oujiang Delta, China

Radiocarbon ◽  
2018 ◽  
Vol 61 (1) ◽  
pp. 83-99
Author(s):  
Daidu Fan ◽  
Shuai Shang ◽  
George Burr
Keyword(s):  
Sea Level ◽  
East China Sea ◽  
Late Quaternary ◽  
Sediment Cores ◽  
East China ◽  
The East China Sea ◽  
China Sea ◽  
Mis 3 ◽  
Plant Matter ◽  
The Last Glacial

ABSTRACTWe describe two coastal paleosols recovered in sediment cores from the Oujiang Delta, Southeast China. These provide useful benchmarks for past sea level change on the East China Sea coast. Radiocarbon (14C) dates on charcoal and plant matter show that one formed during Marine Isotope Stage 3 (MIS 3) and was exposed for perhaps 20 ka, during the Last Glacial Maximum. The other formed in the Early Holocene and was briefly exposed, during a period of fluctuating sea level. Similar paleosols have been described from the Changjiang (Yangtze) Delta, and at many other sites from the East China Sea. The MIS 3 paleosol records a regional relative sea level of about –27 m at the end of MIS 3. While this value is consistent with other paleo sea level estimates for the East China Sea region, it is much higher than predicted by eustatic sea level estimates.

scholarly journals Ice-age ice-sheet rheology: constraints from the Last Glacial Maximum form of the Laurentide ice sheet

2000 ◽  
Vol 30 ◽  
pp. 163-176 ◽  
Author(s):  
W. Richard Peltier ◽  
David L. Goldsby ◽  
David L. Kohlstedt ◽  
Lev Tarasov
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacial Maximum ◽  
Ice Age ◽  
Laurentide Ice Sheet ◽  
Last Glacial ◽  
Flow Law ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractState-of-the-art thermomechanical models of the modern Greenland ice sheet and the ancient Laurentide ice sheet that covered Canada at the Last Glacial Maximum (LGM) are not able to explain simultaneously the observed forms of these cryospheric structures when the same, anisotropy-enhanced, version of the conventional Glen flow law is employed to describe their rheology. The LGM Laurentide ice sheet, predicted to develop in response to orbital climate forcing, is such that the ratio of its thickness to its horizontal extent is extremely large compared to the aspect ratio inferred on the basis of surface-geomorphological and solid-earth-geophysical constraints. We show that if the Glen flow law representation of the rheology is replaced with a new rheology based upon very high quality laboratory measurements of the stress-strain-rate relation then the aspect ratios of both the modern Greenland ice sheet and the Laurentide ice sheet, that existed at the LGM, are simultaneously explained with little or no retuning of the flow law.

scholarly journals Stationary Wave Reflection as a Mechanism for Zonalizing the Atlantic Winter Jet at the LGM

2016 ◽  
Vol 73 (8) ◽  
pp. 3329-3342 ◽  
Author(s):  
Marcus Löfverström ◽  
Rodrigo Caballero ◽  
Johan Nilsson ◽  
Gabriele Messori
Keyword(s):  
North Atlantic ◽  
Wave Breaking ◽  
Planetary Wave ◽  
Wave Reflection ◽  
Stationary Wave ◽  
Laurentide Ice Sheet ◽  
The North ◽  
Nonlinear Reflection ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Current estimates of the height of the Laurentide Ice Sheet (LIS) at the Last Glacial Maximum (LGM) range from around 3000 to 4500 m. Modeling studies of the LGM, using low-end estimates of the LIS height, show a relatively weak and northeastward-tilted winter jet in the North Atlantic, similar to the modern jet, while simulations with high-end LIS elevations show a much more intense and zonally oriented jet. Here, an explanation for this response of the Atlantic circulation is sought using a sequence of LGM simulations spanning a broad range of LIS elevations. It is found that increasing LIS height favors planetary wave breaking and nonlinear reflection in the subtropical North Atlantic. For high LIS elevations, planetary wave reflection becomes sufficiently prevalent that a poleward-directed flux of wave activity appears in the climatology over the midlatitude North Atlantic. This entails a zonalization of the stationary wave phase lines and thus of the midlatitude jet.

scholarly journals High-Resolution Marine Record of Climatic Change in Mid-latitude Chile during the Last 28,000 Years Based on Terrigenous Sediment Parameters

1999 ◽  
Vol 51 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Frank Lamy ◽  
Dierk Hebbeln ◽  
Gerold Wefer
Keyword(s):  
Sediment Cores ◽  
Climatic Conditions ◽  
Sediment Supply ◽  
Size Distributions ◽  
Terrigenous Sediment ◽  
Latitudinal Position ◽  
Grain Size Distributions ◽  
The Last Glacial Maximum ◽  
Southern Westerlies ◽  
The Last Glacial

AbstractMarine sediment cores from the continental slope off mid-latitude Chile (33°S) were studied with regard to grain-size distributions and clay mineral composition. The data provide a 28,000-yr14C accelerator mass spectrometry-dated record of variations in the terrigenous sediment supply reflecting modifications of weathering conditions and sediment source areas in the continental hinterland. These variations can be interpreted in terms of the paleoclimatic evolution of mid-latitude Chile and are compared to existing terrestrial records. Glacial climates (28,000–18,000 cal yr B.P.) were generally cold–humid with a cold–semiarid interval between 26,000 and 22,000 cal yr B.P. The deglaciation was characterized by a trend toward more arid conditions. During the middle Holocene (8000–4000 cal yr B.P.), comparatively stable climatic conditions prevailed with increased aridity in the Coastal Range. The late Holocene (4000–0 cal yr B.P.) was marked by more variable paleoclimates with generally more humid conditions. Variations of rainfall in mid-latitude Chile are most likely controlled by shifts of the latitudinal position of the Southern Westerlies. Compared to the Holocene, the southern westerly wind belt was located significantly farther north during the last glacial maximum. Less important variations of the latitudinal position of the Southern Westerlies also occurred on shorter time scales.

AMS-14C Ages Measured in Deep Sea Cores from the Southern Ocean: Implications for Sedimentation Rates during Isotope Stage 2

1989 ◽  
Vol 31 (2) ◽  
pp. 309-317 ◽  
Author(s):  
Edouard Bard ◽  
Laurent Labeyrie ◽  
Maurice Arnold ◽  
Monique Labracherie ◽  
Jean-Jacques Pichon ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sedimentation Rate ◽  
Deep Sea ◽  
Sediment Cores ◽  
Sea Surface ◽  
Sedimentation Rates ◽  
Deep Sea Sediment ◽  
The Difference ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract14C dates obtained by accelerator mass spectrometry (AMS) on monospecific foraminiferal samples from two deep-sea sediment cores raised in the Indian sector of the Southern Ocean have been corrected for the difference in 14C composition between atmosphere and sea surface by using a reconstruction of the latitudinal 14C gradient which existed in the Southern Ocean prior to 1962. The corrected AMS-14C data show a reduced sedimentation rate in core MD 84-527 between 25,000 and 10,000 yr BP. For core MD 84-551 the available data suggest that the sedimentation rate was higher during the Holocene than during the glacial period. These changes in sedimentation rates may be attributed to an increased opal dissolution during the last glacial maximum.

scholarly journals A numerical investigation of ice-lobe–permafrost interaction around the southern Laurentide ice sheet

2000 ◽  
Vol 46 (153) ◽  
pp. 311-325 ◽  
Author(s):  
Paul M. Cutler ◽  
Douglas R. MacAyeal ◽  
David M. Mickelson ◽  
Byron R. Parizek ◽  
Patrick M. Colgan
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Surface Profile ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
Ice Dynamics ◽  
Last Glacial ◽  
Glacier Ice ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractPermafrost existed around and under marginal parts of the southern Laurentide ice sheet during the Last Glacial Maximum. The presence of permafrost was important in determining the extent, form and dynamics of ice lobes and the landforms they produced because of influences on resistance to basal motion and subglacial hydrology. We develop a two-dimensional time-dependent model of permafrost and glacier-ice dynamics along a flowline to examine: (i) the extent to which permafrost survives under an advancing ice lobe and how it influences landform development and hydrology, and (ii) the influence of permafrost on ice motion and surface profile. The model is applied to the Green Bay lobe, which terminated near Madison, Wisconsin, during the Last Glacial Maximum. Simulations of ice advance over permafrost indicate that the bed upstream of the ice-sheet margin was frozen for 60–200 km at the glacial maximum. Permafrost remained for centuries to a few thousand years under advancing ice, and penetrated sufficiently deep (tens of meters) into the underlying aquifer that drainage of basal meltwater became inefficient, likely resulting in water storage beneath the glacier. Our results highlight the influence of permafrost on subglacial conditions, even though uncertainties in boundary conditions such as climate exist.

The late Quaternary landscape at Sehonghong in the Lesotho highlands, southern Africa

Antiquity ◽  
1996 ◽  
Vol 70 (269) ◽  
pp. 623-638 ◽  
Author(s):  
Peter J. Mitchell
Keyword(s):  
Last Glacial Maximum ◽  
Southern Africa ◽  
Late Quaternary ◽  
Glacial Maximum ◽  
Stone Age ◽  
Later Stone Age ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial ◽  
Rock Shelters

In the rough and rugged country of the Lesotho highlands, rock-paintings and archaeological deposits in the rock-shelters record hunter-gatherer life-ways; at Sehonghong, a long sequence runs from recent times to and through the Last Glacial Maximum. Survey of the region's Middle and Later Stone Age sites shows a pattern of concentrations that likely applies to other parts of the Lesotho highlands.

scholarly journals Underwater faunal assemblages: radiocarbon dates and late Quaternary vertebrates from Cold Lake, Alberta and Saskatchewan, Canada

2018 ◽  
Vol 55 (3) ◽  
pp. 283-294
Author(s):  
Christopher N. Jass ◽  
Devyn Caldwell ◽  
Christina I. Barrón-Ortiz ◽  
Alwynne B. Beaudoin ◽  
Jack Brink ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Faunal Remains ◽  
Radiocarbon Dates ◽  
East Central ◽  
Faunal Assemblages ◽  
History Of ◽  
Cold Lake ◽  
The Last Glacial Maximum ◽  
Insight Into ◽  
The Last Glacial

Late Quaternary faunal remains from three underwater settings in Cold Lake, Alberta and Saskatchewan, Canada, include at least 13 vertebrate taxa consistent with assemblages that postdate the Last Glacial Maximum (LGM). Seven new radiocarbon dates range from 10 350 ± 40 to 161 ± 23 years BP and provide insight into the post-LGM biotic history of east-central Alberta and west-central Saskatchewan. The presence of an essentially modern large mammal biota is suggested for the mid-Holocene, and possibly earlier, if the absence of extinct or extirpated taxa in association with Late Pleistocene Bison at the Alberta–Saskatchewan site is meaningful. Taphonomically, some of the remains suggest deposition in open environments during the Holocene, possibly when lake levels were lower. The recovery of late Quaternary faunal remains from a present-day lacustrine setting is novel, and suggests that similar records may occur in other lakes in western Canada, including those in areas with scarce Quaternary vertebrate records.

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