Seismic Refraction and Reflection Studies in the Timor-Aru Trough System and Australian Continental Shelf1

1979 ◽  
Author(s):  
R. S. Jacobson ◽  
G. G. Shor ◽  
R. M. Kieckhefer ◽  
G. M. Purdy
Keyword(s):  
Continental Shelf ◽  
Seismic Refraction

The East Coast Onshore-Offshore Experiment, II. Seismic refraction measurements on the continental shelf between Cape Hatteras and Cape Fear

1968 ◽  
Vol 58 (3) ◽  
pp. 821-834
Author(s):  
John J. Dowling
Keyword(s):  
Continental Shelf ◽  
East Coast ◽  
Seismic Refraction ◽  
Crystalline Basement ◽  
Well Control ◽  
Depth Contour ◽  
Cape Hatteras ◽  
Near Shore ◽  
Cape Fear ◽  
Refraction Data

abstract During the East Coast OnShore-OffShore Experiment (ECOOE) two lines of instrumented buoys were anchored on the continental shelf between Cape Hatteras and Cape Fear. One line extended from near shore to the 100 fathom depth contour. The other line was parallel to and near the 100 fathom depth contour. Shots varying in size from 20 lbs. to 10 tons were fired along both lines. From the refraction data obtained and well-control available, crystalline basement is correlated with a layer of velocity 5.96 km/sec, the top of the Lower Cretaceous with a layer of velocity 3.54 km/sec and the top of the Upper Cretaceous with a layer of 2.44 km/sec. A contour map of the depth to crystalline basement under the shelf and structure sections are presented. The statistical uncertainties in the depths and velocities were determined.

Seismic observation in the eastern Atlantic, 1952

1954 ◽  
Vol 222 (1150) ◽  
pp. 348-356 ◽  
Keyword(s):  
Continental Shelf ◽  
Sea Level ◽  
Deep Sea ◽  
Sedimentary Cover ◽  
Seismic Refraction ◽  
English Channel ◽  
Basaltic Rocks ◽  
Basement Rocks ◽  
Mohorovičić Discontinuity ◽  
Sedimentary Layer

The seismic refraction shooting experiments undertaken in the eastern Atlantic and on the neighbouring continental shelf are briefly described, and the results compared with previous work. The deep-sea results show that basaltic rocks lie immediately below the sedimentary layer, which is variable in thickness, with a mean of about 1 km. The basaltic rocks extend to the Mohorovičic discontinuity at a depth of between 9 and 13 km below sea-level. The results from the stations on the continental shelf at the mouth of the English Channel confirm that the basement rocks slope gently seaward; the value of this slope and the nature of the sedimentary cover vary with position.

The continental shelf and rifted continental margins of offshore Newfoundland revisited using constrained 3-D gravity inversions: tracking inheritance trends and rift scars

2020 ◽  
Author(s):  
J. Kim Welford ◽  
Meixia Geng
Keyword(s):  
North America ◽  
Continental Shelf ◽  
North Atlantic Ocean ◽  
Seismic Refraction ◽  
Late Triassic ◽  
Moho Depth ◽  
Gravity Inversion ◽  
Continental Margins ◽  
Crust And Upper Mantle ◽  
Rifted Margins

<p>The rifted continental margins of Newfoundland represent one of the best-studied examples of non-volcanic/magma-poor margins in the world. In addition to hosting proven prolific resources within the rift basins on the continental shelf, the rifted margins also host many promising frontier regions for oil and gas exploration in both the Flemish Cap and Orphan basins. Prior to rifting and opening of the North Atlantic Ocean during the breakup of Pangaea, the Newfoundland margins lay conjugate to the Iberian margin to the southeast and the Irish Atlantic margin to the northeast. Rifting and breakup evolved from south to north during three rift phases of varying orientation: NW-SE oriented Late Triassic-Early Jurassic rifting between Iberia/Eurasia and North America, W-E oriented Late Jurassic to Early Cretaceous rifting between Eurasia (Ireland) and North America, and SW-NE oriented Late Cretaceous rifting in the Labrador Sea. While the first phase of rifting exploited pre-existing Caledonian-Appalachian basement structures and tectonic fabrics, later rifting reactivated and crosscut these same inherited structures.</p><p>While multichannel seismic reflection imaging has been extensively undertaken across the Newfoundland shelf and rifted margins, deep crustal structure from seismic refraction profiling has been more sparsely constrained. To interpolate between existing crustal-scale seismic refraction profiles, constrained 3-D gravity inversion has previously been undertaken, providing regional constraints on Moho depth, crustal thickness, and beta factors. However, these early inversion attempts suffered from coarse parameterizations of densities within the sedimentary column and an inability to incorporate sparse deep seismic constraints. In this work, we present 3-D density anomaly models for the crust and upper mantle across the Newfoundland margin using constrained 3-D gravity inversions performed using two independent inversion methodologies (minimum structure and probabilistic). Common features to both inversions are deemed robust and provide an improved regional view of the crustal architecture of the offshore margins. In particular, crustal thinning is observed to align with earlier projections of ancient terrane boundaries such as the boundary between the Avalonian terrane and the Meguma terrane at the southeastern limit of the Grand Banks. Furthermore, the derived crustal thicknesses also provide a clear means of delimiting rafted continental fragments, revealing rift trends and the resulting crustal scars. This is particularly evident for the Orphan Basin where the southeastward rotation and displacement of the Flemish Cap has left a trail of orphaned continental pieces. These form crucial components for future deformable plate reconstructions in GPlates and, until then, provide a detailed regional view of the segmentation of the margin during rifting.</p>

CRUSTAL STRUCTURE ON THE EASTERN SEABOARD OF CANADA: STUDIES ON THE CONTINENTAL MARGIN

1966 ◽  
Vol 3 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Charlotte Keen ◽  
B. D. Loncarevic
Keyword(s):  
Continental Shelf ◽  
Upper Mantle ◽  
Seismic Data ◽  
Seismic Refraction ◽  
Ocean Basin ◽  
Mantle Structure ◽  
Upper Mantle Structure ◽  
Gravity Measurements ◽  
Vertical Density ◽  
Eastern Seaboard

The results of several seismic refraction profiles on the continental shelf and slope of the eastern seaboard of Canada are now available. Gravity measurements which begin near the coast of Nova Scotia and end over the abyssal plain have also been made along two tracks perpendicular to the shelf edge. Various models for the crustal and upper mantle structure are presented. A density distribution assumed for each model resulted in a computed gravity field satisfying the observed gravity measurements. The models in agreement with all seismic data suggest that horizontal and vertical density variations occur in the upper mantle down to 100 km. The results indicate a mantle density of 3.42 g/cm3 under the continental shelf and 3.32 g/cm3 under the ocean basin.

SEISMIC REFRACTION PROFILES ON THE CONTINENTAL SHELF SOUTH OF BELLPORT, LONG ISLAND, NEW YORK

1961 ◽  
Vol 72 (11) ◽  
pp. 1693 ◽  
Author(s):  
M. V. BROWN ◽  
JOHN NORTHROP ◽  
ROBERTO FRASSETTO ◽  
L. H. GRABNER
Keyword(s):  
New York ◽  
Continental Shelf ◽  
Long Island ◽  
Seismic Refraction
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