3D geometry and kinematics of non-colinear fault intersections

Nelson, Mairi A. 2006. 3D geometry and kinematics of non-colinear fault intersections. PhD Thesis, Cardiff University.

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Abstract

Extensional fault arrays at all scales and from different settings, commonly consist of fault sets with different strikes, either due to basement influence, or because of local stress perturbations. These non-colinear fault arrays are characterised by different types of high- angled fault intersections. Significant research has been undertaken into the process and product of colinear fault propagation and linkage in three dimensions, but there is little understanding of the kinematics of multidirectional fault array evolution. Detailed interpretation of the 3D geometry and displacement distributions of intersecting faults has been carried out in four case-study areas in order to further the understanding of kinematic interaction of non-colinear faults. These studies are: a polygonal fault system from the Voring Basin cross-cutting faults from the Gulf of Mexico extensional faults at the tip of a strike-slip fault in the Levant Basin and intersections between grabens trends in Canyonlands National Park, Utah. Intersections display a range of geometries that have been classified into five groups. An intersection may vary between classes within the vertical section. It is not possible to determine the evolutionary style of an intersection by geometry alone but detailed analysis of displacement distributions can reveal the growth histories of the intersecting faults. Faults that meet at high-angled intersections are interpreted to interact kinematically, and show two distinct evolutionary styles: accidental and branching intersections. Accidental intersections form where the intersecting fault propagates toward the main fault plane and relationships that fit this style are defined as abutment, soft and hard linkage and cross- cutting. Evolutionary sequences from abutment to hard linkage, soft to hard linkage and abutment to cross-cutting are identified. Branching intersections form where the intersecting fault propagates away from the main fault plane. A new method for network evolution, termed lateral bifurcation, is proposed for this style of intersection.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Earth and Environmental Sciences
Subjects:	G Geography. Anthropology. Recreation > GE Environmental Sciences
ISBN:	9781303207778
Funders:	The Geological Society Elspeth Matthews Fund, Sir Frank Dixie scholarship
Date of First Compliant Deposit:	30 March 2016
Last Modified:	12 Feb 2016 23:15
URI:	https://orca.cardiff.ac.uk/id/eprint/56138

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