Top Banner

Click here to load reader

Strike-slip Faults and Fabric Variation: Implications for Structural · PDF file 2016. 4. 7. · strike-slip faults and fabric variation: implications for structural and tectonic...

Sep 17, 2020

ReportDownload

Documents

others

  • STRIKE-SLIP FAULTS AND FABRIC VARIATION: IMPLICATIONS FOR STRUCTURAL AND TECTONIC DEVELOPMENT, NORTHERN

    IRON MOUNTAINS, SOUTHWEST VIRGINIA MITCHELL R. SCHARMAN MARSHALL UNIVERSITY

    Support from: Marshall University Summer Research Fund

  • INTRODUCTION

    • Small- to mesoscale strike-slip faults present in Dry Run Gap (DRG)

    • Variation in cleavage orientation

    Map Modified from Bartholomew (1987)

  • Pulaski Block

    Poplar Camp Block

    NORTHERN IRON MOUNTAINS - DRY RUN GAP Map Modified from Stose and Stose (1957)

    1 2

    3

  • CLEAVAGE VARIATION

  • STRIKE-SLIP FAULTS

  • STRIKE-SLIP AND NORMAL FAULTS

  • STRIKE-SLIP AND NORMAL FAULTS

  • STRIKE-SLIP AND NORMAL FAULTS

    (From Fossen, 2011)

    Fault Planes: n = 9

    Strike-slip Faults Normal Faults

  • STRIKE-SLIP OVERPRINT

    Fault Planes: n = 16

  • STRUCTURAL PROGRESSION IMPLICATIONS

    • Cleavage variation during convergence • Initial N-NNE Sinistral and Dextral faults • Cut by normal faults - ~W-WNW trending

    • Syn-Folding? - Orthogonal Flexure? • Late Strike-slip faults - WNW Sinistral and Dextral

    • Syn- to Post-normal fault formation?

    Fault Planes: n = 9

    Strike-slip Faults Normal Faults

  • TECTONIC IMPLICATIONS

    (From Marshak, 2004) DRG - Tangential Extension?

    Map Modified from Bartholomew (1987)

    (From Wise & Werner, 2004)

  • CONCLUSIONS

    • Cleavage orientation variation implies progressive structural changes during imbrication

    • DRG strike-slip faults indicate a more detailed structural progression • Suggest a change in tectonic transport direction • ~N-NNE to WNW • Possibly accommodating convergence change with salient

    interaction

    Strike-slip Faults and Fabric Variation: Implications for Structural and Tectonic Development, Northern Iron Mountains, Southwest Virginia Introduction Northern Iron Mountains - Dry Run Gap Cleavage Variation Strike-slip Faults Strike-slip and Normal Faults Strike-slip and Normal Faults Strike-slip and Normal Faults Strike-slip Overprint Structural Progression Implications tectonic Implications Conclusions