scholarly journals Pre-Wisconsin stratigraphy and paleoclimates off Atlantic Canada, and its bearing on glaciation in Québec

2010 ◽  
Vol 31 (1-2) ◽  
pp. 15-22 ◽  
Author(s):  
M. Alam ◽  
D. J. W. Piper
Keyword(s):  
Continental Shelf ◽  
Ice Sheet ◽  
Atlantic Canada ◽  
Shelf Edge ◽  
Glacial History ◽  
Grand Banks

Cores from tops of seamounts close to the continental shelf west of the Grand Banks contain sequences of alternating clays (representing glacials) and foram nanno ooze (deposited in warmer periods), back to the Pliocene. Although sedimentation in the cores is controlled primarily by glacial conditions on the Grand Banks and Laurentian Channel, glacial history further inland can be inferred. The Wisconsin sequence shows two cool interstadials and one rather warmer one, correlable with the Plum Point, Port Talbot and St. Pierre Interstadials. Clay sedimentation during Wisconsin glacial stages was minor, suggesting glaciers did not extend to the shelf edge. In the late lllinoian, there was a major influx of red sediments, indicating significant erosion of the Gulf of St. Lawrence and Laurentian Channel. Glaciation was more extensive than during the Wisconsin. Two lllinoian interstadials, with temperatures between those of the Plum Point and St. Pierre interstadials are recognised. Early lllinoian glaciation was the most severe yet recognised in the cores. Sedimentation appears to have been controlled by the advance of a Newfoundland — Labrador — E. Québec ice sheet across the Grand Banks.

The Glacial History of the Svalberd Archipelago from Late Vistulian to the Present Time / Historia zlodowacenia archipelagu Svalbard od późnego vistulianu do współczesności

2014 ◽  
Vol 69 (2) ◽  
Author(s):  
Joanna Ćwiąkała ◽  
Mateusz Moskalik ◽  
Jan Rodzik ◽  
Piotr Zagórski
Keyword(s):  
Continental Shelf ◽  
20Th Century ◽  
Ice Sheet ◽  
Ice Age ◽  
The Arctic ◽  
Glacial History ◽  
Svalbard Archipelago ◽  
Maximum Extent ◽  
Late Vistulian ◽  
History Of

AbstractThe glacial history of the Svalbard archipelago is often a hot topic for researches, but the articles usually refer to a particular piece of Svalbard. The authors of this work studied many scientific articles based on the researches to find and collect this history. Svalbard archipelago is located in the Arctic, at the edge of the continental shelf of Europe. The end of shelf boundary noted occurrence of ice caps in the past glaciations. In turn, the main elements of the landscape of the archipelago are glaciers that are currently in a recession. Spitsbergen (the biggest island of the archipelago) sets the limit of Pleistocene glaciations, and the current state of glaciers allows determining the place where the recession is intense. The main aim of the authors in this study is to show this history only from the late Vistulian to the late Holocene (the beginning of 21st century). Interstadials and Stadials start time varies, as their duration in different places, according to various authors. It is very hard to collect all information and describe this history. By knowing the history of glaciation, we can distinguish in the late Vistulian: Last Glacial Maximum (LGM), Bølling/Older Dryas/Allerød and Younger Dryas (YD). LGM was the stadial in which was the maximum extent of ice sheet in late Vistulian. After this period, ice sheet began to retreat from the continental shelf. In turn, YD was the stadial in which the last advance of glaciers took place, about 11 000 years BC. In the Holocene we can distinguish Holocene Climatic Optimum (in the meantime short Cooling Holocene), Revdalen Stadial, Medieval Warm Period, Little Ice Age (LIA) and 20th century warming. The maximum extent of glaciers in Holocene was in LIA. In LIA, the extent of glaciers was bigger than in YD. In 20th century a warming started and continues until now.

Continental Shelf Sediments off Eastern Newfoundland: A Preliminary Investigation

1974 ◽  
Vol 11 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Roger M. Slatt
Keyword(s):  
Continental Shelf ◽  
Preliminary Investigation ◽  
Ice Sheet ◽  
Carbonate Sand ◽  
Grand Banks ◽  
Outer Banks ◽  
Biogenic Carbonate ◽  
The North ◽  
Shelf Sediments ◽  
Sand Sheet

Surficial sediment samples from the continental shelf off eastern Newfoundland were analyzed for grain-size distribution (302 samples) and CaCO3 content (257 samples). The results were compared with those of previous investigations.Gravel covers the inner Grand Banks. Clean, well-sorted sand covers most of the outer banks, but significant quantities of gravel (greater than 10%) are present locally. Biogenic carbonate sand is irregularly distributed on the Grand Banks.The presence of gravel as far seaward as the shelf break indicates the Pleistocene ice sheet once extended across the Grand Banks and the sediments are relict. Other lines of evidence that indicate the sediments are relict include: a radiocarbon date of 17 000 yrs. B.P. on biogenic sand, the occurrence on parts of the shelf of littoral sand now in 90 m of water as well as glacially derived residual sediments, the presence of moraines and a Quaternary shelf sedimentary section 20–200 m thick, and the presence of relict sediments on continental shelves both north and south of the Newfoundland shelf. It is concluded that gravel on the inner Grand Banks is reworked glacial or glacio-fluvial sediment that was deposited during Pleistocene lower stands of sea level and that sand on the outer banks probably was derived by in situ reworking of the Pleistocene substrate during the Holocene transgression.It has previously been suggested that the gravel–sand boundary, which occurs more than 150 km from shore, defines the seaward limit of the Wisconsin ice sheet. This possibility cannot be discounted, however, the presence on the shelf of a transgressive sand sheet, and relict biogenic carbonate sand near this boundary and intermixed with gravel, as well as the Wisconsin glacial history of eastern Newfoundland and Nova Scotia, which suggests late-Wisconsin ice didn't extend offshore a distance of 150 km, all indicate the gravel–sand boundary does not define the seaward limit of Wisconsin ice. The late-Wisconsin ice limit may have been further shoreward.On the North Newfoundland Bank (Ritu Bank) and adjacent areas of the northeast Newfoundland shelf, post-depositional winnowing probably has size-sorted residual sediment according to water depth.

Ice-sheet related landforms at the continental shelf edge, Albatross Bank, Alaska

2016 ◽  
Vol 46 (1) ◽  
pp. 379-380
Author(s):  
H. G. Greene ◽  
J. R. Reynolds ◽  
B. J. Todd
Keyword(s):  
Continental Shelf ◽  
Ice Sheet ◽  
Shelf Edge

scholarly journals Environmental Variation and How its Spatial Structure Influences the Cross-Shelf Distribution of High-Latitude Coral Communities in South Africa

Diversity ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 57 ◽  
Author(s):  
Sean N. Porter ◽  
Michael H. Schleyer
Keyword(s):  
South Africa ◽  
Continental Shelf ◽  
High Latitude ◽  
Environmental Variables ◽  
Environmental Gradients ◽  
High Tide ◽  
Environmental Variation ◽  
Shelf Edge ◽  
Spatial Differences ◽  
Coral Communities

Coral communities display spatial patterns. These patterns can manifest along a coastline as well as across the continental shelf due to ecological interactions and environmental gradients. Several abiotic surrogates for environmental variables are hypothesised to structure high-latitude coral communities in South Africa along and across its narrow shelf and were investigated using a correlative approach that considered spatial autocorrelation. Surveys of sessile communities were conducted on 17 reefs and related to depth, distance to high tide, distance to the continental shelf edge and to submarine canyons. All four environmental variables were found to correlate significantly with community composition, even after the effects of space were removed. The environmental variables accounted for 13% of the variation in communities; 77% of this variation was spatially structured. Spatially structured environmental variation unrelated to the environmental variables accounted for 39% of the community variation. The Northern Reef Complex appears to be less affected by oceanic factors and may undergo less temperature variability than the Central and Southern Complexes; the first is mentioned because it had the lowest canyon effect and was furthest from the continental shelf, whilst the latter complexes had the highest canyon effects and were closest to the shelf edge. These characteristics may be responsible for the spatial differences in the coral communities.

scholarly journals Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz

2010 ◽  
Vol 29 (25-26) ◽  
pp. 3630-3643 ◽  
Author(s):  
Arjen P. Stroeven ◽  
Derek Fabel ◽  
Alexandru T. Codilean ◽  
Johan Kleman ◽  
John J. Clague ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Glacial History ◽  
History Of ◽  
Cordilleran Ice Sheet ◽  
Cosmogenic 10Be ◽  
Northern Sector

scholarly journals Ice sheet-derived submarine groundwater discharge on Greenland's continental shelf

2011 ◽  
Vol 47 (7) ◽  
Author(s):  
Whitney DeFoor ◽  
Mark Person ◽  
Hans Christian Larsen ◽  
Daniel Lizarralde ◽  
Denis Cohen ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Submarine Groundwater Discharge ◽  
Groundwater Discharge ◽  
Ice Sheet ◽  
Submarine Groundwater

Ordovician rocks in the Eastcan et al. Freydis B-87 and other wells in offshore Atlantic Canada

1984 ◽  
Vol 21 (7) ◽  
pp. 864-868 ◽  
Author(s):  
W. A. M. Jenkins
Keyword(s):  
Late Ordovician ◽  
Atlantic Canada ◽  
Grand Banks ◽  
Exploratory Wells

Acritarchs and Chitinozoa from the lower 1300 ft (400 m) of the Eastcan et al. Freydis B-87 well, Labrador Shelf, indicate that these strata accumulated in a marine setting during Late Ordovician time. Five or more other exploratory wells on the Labrador Shelf and the Grand Banks of Newfoundland also have encountered Ordovician rocks.

Low-frequency currents at the northern shelf edge of the Grand Banks

1996 ◽  
Vol 101 (C6) ◽  
pp. 14223-14235 ◽  
Author(s):  
B. M. DeTracey ◽  
C. L. Tang ◽  
P. C. Smith
Keyword(s):  
Low Frequency ◽  
Shelf Edge ◽  
Grand Banks ◽  
Northern Shelf

scholarly journals Morphology and late Cenozoic (<5 Ma) glacial history of the area between David and Mawson Glaciers, Victoria Land, Antarctica

1994 ◽  
Vol 20 ◽  
pp. 55-60
Author(s):  
Anja L.L.M. Verbers ◽  
Volkmar Damm
Keyword(s):  
Ice Sheet ◽  
Field Work ◽  
Topographic Map ◽  
Glacial History ◽  
Ice Surface ◽  
Victoria Land ◽  
Radio Echo Sounding ◽  
History Of ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Glacio-geological field work and radar ice-thickness sounding were carried out in the area between David and Mawson Glaciers. A subglacial topographic map has been compiled from radio-echo-sounding data. The northern part of this map shows that the trench of David Glacier reaches a depth of more than 1000 m below sea level. The area south of David Glacier comprises a landscape of nunatak clusters dissected by glaciated valleys with ice thicknesses as much as 800 m. Subglacial cirques occur at the outer margins of the nunatak clusters. A model for the regional glacial history is proposed. It starts with a major deglaciation in the Pliocene, which results in marine transgression in basins west of the Transantarctic Mountains. During the late Pliocene, the ice advanced towards the northeast, depositing a thin layer of (Sirius Group) till containing reworked mid-Pliocene marine diatoms. Due to accelerated mountain uplift, the ice cut iIlto the pre-Pliocene peneplain, eroding broad valleys. A period of ice-sheet retreat followed to expose a landscape of large nunataks separated by wide valleys. During this period, local cirque glaciation occurred. When the ice sheet advanced again, another phase of uplift forced the glaciers to cut deeper into the valleys. Probably since the Last Glacial Maximum the ice surface has lowered by about 100 m.

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