scholarly journals Oxygen pore water profiles in continental shelf sediments of the North Sea:turbulent versus molecular diffusion

1996 ◽  
Vol 145 ◽  
pp. 63-75 ◽  
Author(s):  
L Lohse ◽  
EHG Epping ◽  
W Helder ◽  
W van Raaphorst
Keyword(s):  
Continental Shelf ◽  
Pore Water ◽  
Molecular Diffusion ◽  
The North ◽  
Shelf Sediments

Latest Quaternary and Holocene paleoceanography of the eastern Baffin Island continental shelf, Canada: benthic foraminiferal evidence

1989 ◽  
Vol 26 (11) ◽  
pp. 2236-2248 ◽  
Author(s):  
Lisa E. Osterman ◽  
Alan R. Nelson
Keyword(s):  
Continental Shelf ◽  
The Arctic ◽  
Baffin Island ◽  
The South ◽  
Baffin Bay ◽  
The North ◽  
Postglacial History ◽  
Foraminiferal Species ◽  
Organic Sediment ◽  
Shelf Sediments

Foraminiferal zones, radiocarbon ages on shells, and corrected ages on pretreated organic sediment from four cores from the eastern Baffin Island continental shelf suggest a three-stage deglacial to postglacial history (Late Wisconsin to Holocene). The earliest sediments in the cores contain foraminiferal species (Elphidium excavatum, Cassidulina reniforme, Islandiella helenae) indicative of distal glaciomarine environments that lasted at least several thousand years. An oceanographic change about 8500 years ago is indicated by a Melonis zaandamae zone in northern and central shelf cores collected from 200–800 m water depth. The presence of M. zaandamae in the north and its absence in the south suggest warmer and more saline postglacial water in northern Baffin Bay, whose influence became diluted with cooler coastal meltwater as the current flowed south along the Baffin Island Shelf. Sediments after 6000 years ago on the northern and central shelf are dominated by agglutinated foraminifera, suggesting dissolution of calcareous species. This dissolution event, which affected deeper water cores sooner than cores from the shelf, may be related to the influx of cold, CO2-rich water from the Arctic Ocean during the mid-Holocene. Thus, postglacial oceanographic changes in Baffin Bay appear first in deep northern waters; the lag time in the response to these changes in the shallower water on the shelf and to the south may have been as long as several thousand years.

Molecular characterization of dissolved organic matter in pore water of continental shelf sediments

2009 ◽  
Vol 73 (11) ◽  
pp. 3337-3358 ◽  
Author(s):  
Frauke Schmidt ◽  
Marcus Elvert ◽  
Boris P. Koch ◽  
Matthias Witt ◽  
Kai-Uwe Hinrichs
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Continental Shelf ◽  
Molecular Characterization ◽  
Pore Water ◽  
Shelf Sediments

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.

The Recent Cypraeidae of Northern New Zealand from the Kermadec Islands to the Poor Knights Islands, Southwest Pacific Ocean (Mollusca: Gastropoda: Cypraeidae)

The Festivus ◽  
2018 ◽  
Vol 50 (1) ◽  
pp. 36-54
Author(s):  
John Daughenbaugh
Keyword(s):  
New Zealand ◽  
Pacific Ocean ◽  
Continental Shelf ◽  
East Coast ◽  
Species Distributions ◽  
East Side ◽  
Tropical Eastern Pacific ◽  
The North ◽  
The Poor ◽  
Coastal Shelf

For researchers, isolated regions at the periphery of species’ distributions hold a peculiar fascination. The causes of their remoteness vary based on: distance (e.g. the Tropical Eastern Pacific), distance and countervailing currents (e.g. the Marquesas), location in a present day gyre (e.g. the Pitcairn Group) or the absence of present day means of veliger transport (e.g. the Vema Seamount). (Daughenbaugh & Beals 2013; Daughenbaugh 2015a & b, 2017). The northern New Zealand Region from the Kermadec Islands (Kermadecs) to the coastal and shelf areas in the northernmost part of New Zealand’s North Island (Northland), including the Poor Knights Islands (PKI), constitute the distributional boundaries for a number of Cypraeidae species. The boundaries are the result of the absence of coastal shelves along the east side of the Kermadec Ridge (Ridge) and precipitous drops to abyssal depths along Northland’s east coast continental shelf. Tropical waters, with their potential to transport Cypraeidae larvae, flow eastward from southern Queensland, Australia, entrained in the Tasman Front which terminates when reaching North Cape, the northernmost tip of Northland. There, the North Cape Eddy captures most of this flow while the remainder, the East Auckland Current (EAUC), flows intermittently southward along the eastern coastal, shelf and offshore areas of Northland into waters incapable of supporting Cypraeidae populations.

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