Anomalous Concentration of Methane Emissions at the Continental Shelf Edge of the Northern Cascadia Margin

2019 ◽  
Vol 124 (3) ◽  
pp. 2829-2843 ◽  
Author(s):  
H. Paul Johnson ◽  
Susan Merle ◽  
Marie Salmi ◽  
Robert Embley ◽  
Erica Sampaga ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Methane Emissions ◽  
Shelf Edge ◽  
Cascadia Margin

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.

Erosional furrows on continental shelf edge, Mississippi delta region

1981 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
James M. Coleman ◽  
David B. Prior ◽  
Charles E. Adams
Keyword(s):  
Continental Shelf ◽  
Mississippi Delta ◽  
Shelf Edge ◽  
Delta Region

Bathymetry and acoustic facies beneath the former Larsen-A and Prince Gustav ice shelves, north-west Weddell Sea

2001 ◽  
Vol 13 (3) ◽  
pp. 312-322 ◽  
Author(s):  
Carol J. Pudsey ◽  
Jeffrey Evans ◽  
Eugene W. Domack ◽  
Peter Morris ◽  
Rodolfo A. Del Valle
Keyword(s):  
Continental Shelf ◽  
Weddell Sea ◽  
Shelf Edge ◽  
Ice Shelf ◽  
Ice Shelves ◽  
North West ◽  
Preliminary Results ◽  
The Past ◽  
Acoustic Facies ◽  
Marine Mud

We present preliminary results of the first detailied surveys of the former Larsen-A Ice Shelf, Larsen Inlet and southern Prince Gustav Channel, where disintegration of small ice shelves in the past ten years has exposed the seafloor. Glacial troughs in the Larsen-A area, Larsen Inlet and Prince Gustav Channel reach 900–1100 m depth and have hummocky floors. Farther south-east, the continental shelf is shallower (400–500 m) and its surface is fluted to smooth, with the density of iceberg furrowing increasing towards the shelf edge. Acoustic profiles show a drape of transparent sediment 4–8 m thick in Prince Gustav Channel, thinning southwards. In cores, this drape corresponds to diatom-bearing marine and glacial-marine mud. In the Larsen-A area and Larsen Inlet, acoustically opaque sediment includes proximal ice shelf glaciomarine gravelly and sandy muds, and firm to stiff diamicts probably deposited subglacilly. These are overlain by thin (up to 1.3 m) glaciomarine muds, locally with distinctive diatom ooze laminae.

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.

Shelf-edge deltas and drowned barrier–island complexes on the northwest Florida outer continental shelf

Geomorphology ◽  
2005 ◽  
Vol 64 (3-4) ◽  
pp. 133-166 ◽  
Author(s):  
J.V. Gardner ◽  
P. Dartnell ◽  
L.A. Mayer ◽  
J.E. Hughes Clarke ◽  
B.R. Calder ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Barrier Island ◽  
Shelf Edge ◽  
Outer Continental Shelf ◽  
Northwest Florida

Offset Dependent Static Corrections on a Continental Shelf Edge 3D Seismic Survey

1991 ◽  
Vol 22 (1) ◽  
pp. 75-80
Author(s):  
M. G. Cousins ◽  
P. M. Whiting ◽  
A. M. Allen
Keyword(s):  
Continental Shelf ◽  
Seismic Survey ◽  
Shelf Edge ◽  
3D Seismic ◽  
Static Corrections
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