scholarly journals High-resolution seismic-reflection profiles and sidescan-sonar records collected on Block Island Sound by U.S. Geological Survey, R/V ASTERIAS, cruise AST 81-2

1982 ◽  
Author(s):  
S. W. Needell ◽  
R.S. Lewis
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Geological Survey ◽  
Sidescan Sonar ◽  
Block Island ◽  
Seismic Reflection Profiles ◽  
Island Sound

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.

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