GEOL 460: Week 2

Week 2 Course Material


  • Lab 2: Plate Motion Rates

    Additional Resources

  • Here is a paper from 2012 that discusses the northward migration of the Mendocino triple junction from McLaughlin et al. (2012).
  • This is a summary figure from their paper. I include their text as blockquote below.

    Schematic maps showing successive reorganizations of the Rodgers Creek–Maacama fault system with time in relation to adjacent northward migration of restraining and releasing bend geometries of the northern San Andreas fault zone in the wake of the Mendocino Triple Junction. F.Z.—fault zone; U—upthrown; D—downthrown. Time windows are shown beginning ca. 7 Ma, with formation of the buried transtensional basin beneath Santa Rosa Plain. The fault system is seen to undergo successive reorganizations in response to the encroachment and passage of the releasing bend segment of the San Andreas fault zone between 7 Ma and the present. Continual northward lengthening of the transform margin imposes significant changes in fault geometry on the area east of the Mendocino Triple Junction because of the bending northern San Andreas fault geometry. In detail, the succession of compressional and extensional deformation in evolution of the Rodgers Creek–Maacama fault system appears to be a necessary response at the south end of the fault system to continual fault zone lengthening and reorganization at its northern end as the Mendocino Triple Junction propagates. Active faults for indicated time windows are shown in red; inactive faults in blue. Purple double-pointed arrows indicate orientation of active extension (arrows point away from each other) or compression (arrows point toward each other). Double-pointed blue arrows show inferred areas of formerly active transtension or transpression. Green and dark gray circle symbols bisected by the Rodgers Creek and Maacama fault zones are arbitrary reference points illustrating offset across the Rodgers Creek (green circle) and Maacama (dark gray circle) fault zones, based on displacements established in this paper (Table 3).

    Reference: McLaughlin, R.J., Sarna-Wojcicki, A.M., Wagner, D.L., Fleck, R.J., Langenheim, V.E., Jachens, R.C., Clahan, K., and Allen, J.R., 2012. Evolution of the Rodgers Creek–Maacama right-lateral fault system and associated basins east of the northward-migrating Mendocino Triple Junction, northern California in Geosphere, v. 8, no. 2, p. 342-372.

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