scholarly journals Notes on the acquisition of high resolution seismic reflection profiles, side-scanning sonar records, and sediment samples from lower Cook Inlet and Kodiak Shelf, R/V Sea Sounder Cruise S8-78-WG, August 1978

1979 ◽  
Author(s):  
Monty A. Hampton ◽  
Arnold H. Bouma
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Cook Inlet ◽  
Sediment Samples ◽  
Seismic Reflection Profiles

Unconformities on the Scotian Shelf

1974 ◽  
Vol 11 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Lewis H. King ◽  
Brian MacLean ◽  
Gordon B. Fader
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Upper Cretaceous ◽  
Scotian Shelf ◽  
Early Tertiary ◽  
Late Tertiary ◽  
Glacial Processes ◽  
Well Data ◽  
Seismic Reflection Profiles ◽  
Cut And Fill

Four erosional unconformities have been recognized within the Mesozoic-Cenozoic succession on the Scotian Shelf, on the basis of data from high resolution seismic reflection profiles. Older unconformities are known from well data and others may be revealed by detailed biostratigraphic studies.The oldest of the four unconformities discussed in this paper is of Early Cretaceous age and appears to mark, with discordance, the boundary between Jurassic and Cretaceous strata on the western part of the shelf. A second angular unconformity, of Late Cretaceous age, has been recognized on the central part of the shelf where the basal part of the Banquereau Formation (Tertiary and uppermost Cretaceous) oversteps the zero-edge of the Wyandot Formation (Upper Cretaceous) and lies upon truncated beds of the Dawson Canyon Formation (Upper Cretaceous). Cut-and-fill relationships characterize a third unconformity developed during Early Tertiary time. A fourth unconformity was developed in Late Tertiary – Pleistocene time by fluvial processes and later by glacial processes. Although in many areas the latest unconformity appears to be the most conspicuous one on the shelf, its configuration closely follows the geomorphic expression developed during the previous period of erosion. The regional extent of the Cretaceous unconformities is not known, and they might only occur near basin margins and on structural and basement highs.

scholarly journals The marine record of the Russell Fiord outburst flood, Alaska, U.S.A.

1996 ◽  
Vol 22 ◽  
pp. 194-199 ◽  
Author(s):  
Ellen A. Cowan ◽  
Paul R. Carlson ◽  
Ross D. Powell
Keyword(s):  
High Resolution ◽  
Debris Flow ◽  
Seismic Reflection ◽  
Seismic Facies ◽  
Turbidity Currents ◽  
Outburst Flood ◽  
Gravity Core ◽  
Channel System ◽  
Seismic Reflection Profiles ◽  
Long Channel

The advance of Hubbard Glacier, near Yakutat, Alaska, U.S.A., in spring 1986 blocked the entrance to Russell Fiord with an ice-and-sediment dam, behind which a lake formed. The water level in Russell Lake rose to 25.5 m a.s.l. The dam catastrophically failed in October 1986, releasing 5.4 km3of water into Disenchantment Bay. High-resolution seismic-reflection profiles show a 7.5 km long channel system cut into and buried by glacimarine sediment, represented by continuous, parallel reflections. The chaotic seismic facies filling the channel is interpreted to be debris flow deposits. A gravity core from channel-overbank deposits contained sandy diamicton with mud clasts. Above the channel a 1–2 m thick sediment drape extends across the bay. Laminated mud, fining-upward sand beds and diamicton were recovered from this unit. The sediment-drape deposits were produced by suspension settling from turbid plumes and non-channelized turbidity currents generated by the outburst flood.

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