Variations in rifting style and structure of the Scotian margin, Atlantic Canada, from 3D gravity inversion
Published:January 01, 2013
S. A. Dehler, J. K. Welford, 2013. "Variations in rifting style and structure of the Scotian margin, Atlantic Canada, from 3D gravity inversion", Conjugate Divergent Margins, W. U. Mohriak, A. Danforth, P. J. Post, D. E. Brown, G. C. Tari, M. Nemčok, S. T. Sinha
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Regional gravity data and a three-dimensional (3D) inversion approach were used to examine variations in crustal thickness and to extend seismic-based interpretations along the Scotian margin, Atlantic Canada. Constraints on Moho, crust and sedimentary layers were based on seismic refraction models and profiles of deep multichannel seismic data. A subsurface 3D density anomaly distribution was developed, using initial constraints from bathymetric data and seismic basement depth estimates, and inverting for crustal and subcrustal geometries. Predictions from the model include regional maps of Moho structure, crustal thickness and stretching factor. Depth slices allow comparison with seismic interpretations along three transects. The model predictions of variable width of crustal extension and northward thinning of oceanic crust agree with the seismic profiles. The density anomaly model shows significantly greater thinning and numerous block faulting beneath the northern margin and more uniform thinning to the SW. The fairly sharp transition between the two regions may be explained by a transfer zone separating different rifting regimes.
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Conjugate Divergent Margins
The main focus of the book is the geological and geophysical interpretation of sedimentary basins along the South, Central and North Atlantic conjugate margins, but concepts derived from physical models, outcrop analogues and present-day margins are also discussed in some chapters. There is an encompassing description of several conjugate margins worldwide, based on recent geophysical and geological datasets. An overview of important aspects related to the geodynamic development and petroleum geology of Atlantic-type sedimentary basins is also included. Several chapters analyse genetic mechanisms and break-up processes associated with rift-phase structures and salt tectonics, providing a full description of conjugate margin basins based on deep seismic profiles and potential field methods.