EVOLUTION OF A STRIKE-SLIP FAULT NETWORK IN SANDSTONE Eric Flodin Stanford University, Stanford, CA 94305 email:
[email protected] Abstract Faults formed by shearing along preexisting This paper is a progress report on research concerning discontinuities the evolution of strike-slip networks in sandstone. In the A solid basis exists in the literature for understanding the Valley-of-Fire State Park of southern Nevada, the Juras- initiation and evolution of faults formed along preexisting sic Aztec sandstone is deformed by two strike-slip fault discontinuities. Much of the early work concerning fault sets with different orientations and opposite slip sense. formation and evolution were focused in granites (Segall One fault set is oriented north-northeasterly and shows and Pollard, 1983; Granier, 1985; Martel et al., 1988; apparent left-lateral displacements up to 2.4 km. The other Martel 1990). Other workers have extended these concepts fault set is oriented northwesterly and shows apparent to other lithologies including carbonates (e.g., Willemse right-lateral offsets up to 50 m. At a regional scale, most et al., 1997; Mollema and Antonellini, 1999; Graham et of the right-lateral faults terminate against the larger- al., in review), shales (e.g., Engelder et al., 2001), and sand- offset left-lateral faults and are found localized both be- stones (e.g., Cruikshank et al., 1991; Zhao and Johnson, tween step regions along individual left-lateral faults, 1992; Myers, 1999; Davatzes and Aydin, in review). as well as at the ends of the larger left-lateral faults. At a Joint-based faulting as a prominent deformation smaller scale, right- and left-lateral faults show mutu- mechanism in sandstone was first described by Myers ally abutting relationships.