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Pure Appl. Geophys. 171 (2014), 28992918 2014 Springer Basel
DOI 10.1007/s00024-014-0826-7 Pure and Applied Geophysics
Formation and Suppression of StrikeSlip Fault Systems
IVY S. CURREN1 and PETER BIRD1
AbstractStrikeslip faults are a dening feature of plate tectonics, yet many aspects of their development and evolution remain unresolved. For intact materials and/or regions, a standard sequence of shear development is predicted from physical models and eld studies, commencing with the formation of Riedel shears and culminating with the development of a throughgoing fault. However, for materials and/or regions that contain crustal heterogeneities (normal and/or thrust faults, joints, etc.) that predate shear deformation, kinematic evolution of strikeslip faulting is poorly constrained. We present a new plane-stress nite-strain physical analog model developed to investigate primary deformation zone evolution in simple shear, pure strikeslip fault systems in which faults or joints are present before shear initiation. Experimental results suggest that preexisting mechanical discontinuities (faults and/or joints) have a marked effect on the geometry of such systems, causing deection, lateral distribution, and suppression of shears. A lower limit is placed on shear offset necessary to produce a throughgoing fault in systems containing preexisting structures. Fault zone development observed in these experiments provides new insight for kinematic interpretation of structural data from strikeslip fault zones on Earth, Venus, and other terrestrial bodies.
Key words: Strikeslip faults, analog modeling, wet kaolin, brothers fault zone, SISZ, venus.
1. Introduction
On Earth, regions dominated by toroidal (shear) motion are characterized by faults with heave parallel to their strike (BATES and JACKSON 1987), which are known as strikeslip in continental settings or transform faults in oceanic settings. They are responsible for accommodating motion between plates and between offset spreading ridges, rotating blocks, and within compressional orogens. Unlike normal and thrust faults along which area is gained or lost by extension or compression, respectively, strikeslip
faults conserve area by sliding horizontally along approximately vertical fault planes (OCONNELL et al. 1991; SLEEP 1992). Their lateral motion produces horizontal offsets that are easily identied in plan view; as a result, strikeslip faults are ideal candidates for identifying and reconstructing tectonic processes and histories on terrestrial planets and satellites (SLEEP 1994; YIN 2012).
Physical analog models (CLOOS 1928; RIEDEL
1929; EMMONS 1969; TCHALENKO 1970; WILCOX et al. 1973; HILDEBRAND-MITTLEFEHLDT...