Lateral variation of the crustal structure of a passive margin: a case study of the Eastern North American Margin

A novel study based primarily on little-used seismic reflection data along the Eastern North American Margin has provided valuable insights into the true lateral variation in geometries and crustal architectures in a passive margin setting that was previously thought to very much belong to the 'magma-rich' end-member archetype.
This study indicates that the true variability of passive margins cannot be accurately represented in models. Specifically, magmatic additions along ENAM, while previously thought to be a thick, continuous volcanic wedge of extrusive seaward-dipping reflectors, is considerably more complex. The seaward-dipping reflectors are isolated to the very north of the margin, and sit within a segment that can be clearly defined, both from geological (seismic reflection data) and geophysical (potential fields data) interpretations. Further segmentation when moving along-strike indicates the considerable lateral variability at ENAM, and gives insights into the potential role of inheritance and how significant pre-existing weaknesses may be in producing the unique physignomy and geometries interpreted along-strike. A potential transfer zone at Cape Hatteras can be confirmed from synthesising both the seismic reflection and potential fields interpretations, while multiple scales/orders of segmentation are evident; longer wavelength (100's of km scale) from changes in textures of gravity and magnetic data; and small scale (20-100km) changes along-strike from interpreting seismic reflection data.
The combination of both seismic reflection and potential fields data at this margin in attempting to produce an unbiased interpretation, away from accepted models and nomenclature, has provided particularly valuable insights and can provide valuable example and evidence for this practice to be utilised elsewhere to capture true lateral variability at passive margins.