scholarly journals Availability of single channel seismic reflection profiles collected over U.S. Atlantic continental slope and rise north of Cape Hatteras-USGS cruises FAY 20 and FAY 21, August/September 1976

1979 ◽  
Author(s):  
Kim D. Klitgord
Keyword(s):  
Continental Slope ◽  
Seismic Reflection ◽  
Single Channel ◽  
Cape Hatteras ◽  
Seismic Reflection Profiles

Evidence for Wisconsinan Glaciations in the Verrill Canyon Area, Scotian Slope

1989 ◽  
Vol 31 (1) ◽  
pp. 27-40 ◽  
Author(s):  
David C. Mosher ◽  
David J. W. Piper ◽  
Gustavs V. Vilks ◽  
A. E. Aksu ◽  
Gordon B. Fader
Keyword(s):  
High Resolution ◽  
Continental Slope ◽  
Seismic Reflection ◽  
Outer Shelf ◽  
Scotian Shelf ◽  
Radiocarbon Dates ◽  
Oxygen Isotopic ◽  
Late Wisconsinan ◽  
Seismic Reflection Profiles ◽  
Water Depths

AbstractA composite thickness of about 25 m of sediment has been cored from the Verrill Canyon on the Scotian Slope. It is interpreted that the majority of this sequence was deposited in a glaciomarine environment during oxygen isotopic stage 2 and the top of stage 3. These sediments, as seen in high-resolution seismic reflection profiles, are well stratified, become thicker upslope, are laterally variable in thickness, and pass upslope into possible outer shelf tills. Three wedge-shaped units of incoherent reflections interfinger with the parallel reflections and terminate in water depths greater than 700 m. These wedge-shaped units are interpreted as slumped diamict and outwash deposits. The age of the uppermost wedge-shaped unit is 26,000–21,000 yr based on extrapolation of radiocarbon dates. This unit documents a late Wisconsinan glacier readvance on the outer Scotian Shelf. The underlying wedge-shaped unit, estimated to be 70,000 yrs old, extends further west along the continental slope, and may represent a more extensive early Wisconsinan ice advance. A third wedge-shaped unit, inferred to have formed during isotopic stage 6, is possibly a remnant of the first glaciation in the study area.

Seismic investigations of sedimentary structure in the northern Rockall Trough—a synopsis

1986 ◽  
Vol 88 ◽  
pp. 53-54
Author(s):  
R. J. Whittington ◽  
M. R. Dobson
Keyword(s):  
Seismic Reflection ◽  
Single Channel ◽  
Sedimentary Structure ◽  
The North ◽  
Air Gun ◽  
Late Tertiary ◽  
Rockall Trough ◽  
Seismic Reflection Profiles ◽  
Small Capacity ◽  
North Rockall Trough

Single channel, analogue, seismic reflection profiles using Sparker and small capacity Air gun sources were used to investigate late Tertiary and Quaternary sedimentation both around the margins and on the floor of the north Rockall Trough. The data complement, by being intermediate in penetration and resolution, previous seismic studies; particularly, they allow the upper 500 m of the sediment sequence to be examined in greater detail than hitherto.

Probable Late Wisconsinan ice margin on the upper continental slope off St. Pierre Bank, eastern Canada

1988 ◽  
Vol 25 (6) ◽  
pp. 853-865 ◽  
Author(s):  
Denis Bonifay ◽  
David J. W. Piper
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Seismic Reflection ◽  
Radiocarbon Dating ◽  
Shear Stresses ◽  
Eastern Canada ◽  
Late Wisconsinan ◽  
Acoustic Facies ◽  
Seismic Reflection Profiles ◽  
Basal Shear

Seismic reflection profiles from the continental slope off St. Pierre Bank show a distinctive acoustic facies characterized by incoherent reflections (unit E) overlain by 5–20 m of stratified sediments (units D–A). Cores from unit E include poorly sorted silty diamict, locally overconsolidated and including in places some foraminifera. Stratified sediments also occur in places in this facies.The overlying sediments of units D–A, except for the topmost metre of unit A, have a foraminiferal fauna dominated by Elphidium excavatum forma clavata and Cassidulina reniforme, which has been interpreted elsewhere as indicating ice-margin sedimentation. The sediments contain turbidites and rare ice-rafted detritus, and are bioturbated. Accelerometer mass spectrometer radiocarbon dating of shells from the stratified sediments yielded dates between 3.3 and 11.8 ka. Facies E, the top of which has an extrapolated age of 11.5–12.0 ka, is interpreted as slumped morainal diamict and proglacial sediment resulting from a late Wisconsinan ice surge through Halibut Channel. Low basal shear stresses in this thin ice surge left little record in the mud-accumulating basins of the continental shelf.

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