Over the last few years, the introduction of linked fault models has revolutionized our ability to use industry reflection seismic data in the interpretation of structures developed in extensional basins. The subsidence history of basins or grabens used to monitor crustal extension (the Beta factor) is generally incompatible with that measured from the ubiquitous steep normal faults often interpreted on seismic or field data. The fault systems must reflect a mechanical system that can permit upper crustal extension to match crustal thinning derived from subsidence data.
An extensional fault system must comprise steep fault segments (ramps) which join shallow or sub-horizontal detachments (flats) in the extension or slip direction, both of which are compartmentalized by linked transfers or sidewalls. Linked systems may be small enough to be measured in meters or large enough to involve the entire crust, and per-haps the lithosphere. The detailed geometry and sequence of movement on the linked system directly controls the dip and strike development of the sedimentary fill, its facies, and the second-order faulting within the sediments. Conversely, the linked fault geometry and its movement history can be deduced by applying balanced-section techniques to the stratigraphic section, first in two dimensions (2D) and then in three dimensions (3D). This allows either structure or stratigraphy to be predicted in a systematic way from a knowledge of the other.
Figures & Tables
Extensional Tectonics and Stratigraphy of the North Atlantic Margins
Stimulated by the wealth of frontier exploration data and deep seismic surveys about the North Atlantic margins, this publication was crafted to provide a comprehensive analysis of North Atlantic extension. The 40 papers in this volume are divided into 6 sections: concepts, North Atlantic perspectives, North American margins, European-African margins, North Sea and Barents Shelf, and analogs. This book is concerned primarily with the circum-North Atlantic data base. It is largely biased toward presentation and interpretation of data rather than being model driven. The book includes comparative stratigraphic columns for basins of the North Atlantic margins.