1887
Volume 7 Number 2
  • E-ISSN: 1365-2117

Abstract

Abstract

Extensive sheets of monolithological breccia (megabreccia) within detachment‐fault systems of the North American Cordillera have been identified as large landslides. Although the origin of the megabreccia deposits is controversial, their spatial and temporal association with detachment‐fault systems implies a causal relationship between the initiation of such landslides and motion along detachment faults. Emplacement may have been catastrophic following seismic activity, or slow, as the result of gravity gliding. Nevertheless, comprehensive analysis of these deposits provides important constraints on the evolution of supradetachment basins by detailing the unroofing history, palaeotopography and palaeoseismicity of detachment‐fault systems. An extensive Miocene landslide deposit, the War Eagle landslide, in the north‐eastern Whipple Mountains, provides an opportunity for such an endeavour to elucidate: (1) the cause and timing of its initiation; (2) mechanism for its emplacement; (3) nature of the apparent association of the landslide with detachment‐fault development; and (4) role of the megabreccia in the development of supradetachment basins. Cross‐sections were drawn through the deposit to determine the geometry and kinematic development of the landslide. Additionally, a simple mechanical model based on limit equilibrium force balance was designed to explore physical mechanisms that controlled its creation. The results of this model combined with field relationships suggest that the Whipple detachment fault was active at an angle of less than 30° with displacement most likely accompanied by the release of seismic energy. Continued extensional evolution of the Whipple detachment fault caused tilting of the upper‐plate strata and the formation of numerous half and full grabens as well as roll‐over structures. Rocks from the lower plate were brought to the surface during the later stages of detachment‐fault activity thereby producing sufficient topographic relief for large landslides to be seismically activated. Increased pore‐fluid pressure in the footwall subjacent to the Whipple detachment fault probably aided landslide initiation. The landslide was emplaced onto the upper plate of the detachment fault, providing a significant amount of material into the evolving supradetachment basin. Although the rate of emplacement of the megabreccia remains uncertain, penetrative fracturing throughout the breccia sheet is evidence that emplacement occurred catastrophically. The results of this study indicate that Tertiary megabreccias were emplaced during continued detachment‐fault evolution, implying oversteepened topography and seismicity of these low‐angle systems.

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2007-11-06
2024-03-29
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References

  1. Anderson, J. L. & Cullers, R. L. (1990) Middle to upper crustal plutonic construction of a magmatic arc; an example from the Whipple Mountains metamorphic core complex. In: The Nature and Origin of Cordilleran Magmatism (Ed. by J. L.Anderson). Mem. geol. Soc. Amer. 174, 47–69.
  2. Axen, G. J. (1988) The geometry of planar domino‐style normal faults above a dipping basal detachment. J. struct. Geol., 10, 405–411.
    [Google Scholar]
  3. Axen, G. J. (1992) Pore pressure, stress increase, and fault weakness in low‐angle normal faulting. 3. geophys. Res., 97, 8979–8991.
    [Google Scholar]
  4. Campbell, C. S. (1989) Self‐lubrication for long run out landslides. J. Geol., 97, 653–665.
    [Google Scholar]
  5. Coney, P. J. (1980) Cordilleran metamorphic core complexes: an overview. Mem. geol. Soc. Am., 153, 7–31.
    [Google Scholar]
  6. Coulson, J. H. (1972) Shear strength of flat surfaces in rock. In: Stability of Rock Slopes (Ed. by E. J.Cording ), pp. 77–105. American Society of Civil Engineers, New York .
    [Google Scholar]
  7. Davies, T. R. H. (1982) Spreading of rock avalanche debris by mechanical fluidization. Rock Mechanics, 15, 9–24.
    [Google Scholar]
  8. Davis, G. A. (1988) Rapid upward transport of mid‐crustal mylonitic gneisses in the footwall of a Miocene detachment fault, Whipplc Mountains, southeastern California. Geol. Rdsch., 77, 191–209.
    [Google Scholar]
  9. Davis, G. A., Anderson, J. L., Frost, E. G. & Shackelford, T. J. (1980) Mylonitization and detachment faulting in the Whipple‐Bucksin‐Rawhide Mountains terrane, southeastern California and Western Arizona. Mem. geol. Soc. Am., 153, 79–129.
    [Google Scholar]
  10. Davis, G. A., Anderson, J. L., Krummenacher, D., Frost, E. G. & Armstrong, R. L. (1982) Geolgic and geochronologic relations in the lower plate of the Whipple detachment fault, Whipple Mountains, southeastern California: a progress report. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona, and Nevada (Ed. by E. G.Frost and D. L.Martin ), pp. 408–432. Cordilleran Publishers, San Diego .
    [Google Scholar]
  11. Davis, G. A. & Lister, G. S. (1988) Detachment faulting in continental extension; perspectives from the southwestern U.S. Cordillera. Spec. Pap. geol. Soc. Am., 218, 133–159.
    [Google Scholar]
  12. Davis, G. A., Lister, G. S. & Reynolds, S. J. (1986) Structural evolution of the Whipple and South mountains shear zones, southwestern United States. Geology, 14, 7–10.
    [Google Scholar]
  13. Dickinson, W. R. (1991) Tectonic setting of faulted Tertiary strata associated with the Catalina core complex in southern Arizona. Spec. Pap. geol Soc. Am., 264, 52–54.
    [Google Scholar]
  14. Dorsey, R. J., Dunlap, J. & Becker, U. (1993) A large growth structure in the Miocene north Whipple Basin: implications for upper‐plate evolution. Geol. Soc. Am. Abstracts with Programs, 25, 352.
    [Google Scholar]
  15. Dula, W. F. (1991) Geometric models of listric normal faults and rollover folds. Bull. Am. Ass. petrol. Geol., 75, 1609–1625.
    [Google Scholar]
  16. Dunn, J. F. (1986) The structural geology of' the northeastern Whipple Mountains detachment fault terrane, San Bernardino County. California. MS thesis, Los Angeles , University of Southern California.
  17. Erismann, T. H. (1979) Mechanisms of large landslides. Rock Mechanics, 12, 15–46.
    [Google Scholar]
  18. Fedo, C. M. & MillerJ. M. G. (1992) Evolution of a Miocene half‐graben basin, Colorado River extensional corridor, southeastern California. Bull. geol. Soc. Am., 104, 481–493.
    [Google Scholar]
  19. Forshee, E. J. & Yin, A. (1993) A model for initiation of a mid‐Tertiary rock avalanche in the Whipple Mountains area, SE California: implications for seismicity along low‐angle detachment faults. Geol. Soc. Am. Abstracts with Programs, 25, 351.
    [Google Scholar]
  20. Ghosh, A. & Haupt, W. (1989) Computation of the seismic stability of rock wedges. Rock Mechanics Engng, 22, 109–125.
    [Google Scholar]
  21. Gottschalk, R. R., Kronenberg, A. K., Russell, J. E. & Handin, J. (1990) Mechanical anisotropy of gneiss: failure criterion and textural sources of directional behavior. J. geophys. Res., 95, 21,613–21,634.
    [Google Scholar]
  22. Gross, W. W. & Hillemeyer, F. L. (1982) Geometric analysis of upper‐plate fault patterns in the Whipple‐Buckskin detachment terrane, California and Arizona. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona, and Nevada (Ed. by E. G.Frost and D. L.Martin ), pp. 257–265. Cordilleran Publishers, San Diego .
    [Google Scholar]
  23. Guth, P. L., Hodges, K. V. & Willemin, J. H. (1982) Limitations on the role of pore pressure in gravity gliding. Bull. geol. Soc. Am., 93, 606–612.
    [Google Scholar]
  24. Hauge, T. A. (1990) Kinematic model of a continuous Heart Mountain allochthon. Bull. geol. Soc. Am., 102, 1174–1188.
    [Google Scholar]
  25. Howard, K. A. & John, B. E. (1987) Crustal extension along a rooted system of imbricate low‐angle faults: Colorado River extensional corridor, California and Arizona. In: Contrnental Extensional Tectonics (Ed. by M. P.Coward, J. F.Dewey and P. L.Hancock). Spec. Pap. geol. Soc. London. 28, 299–312.
  26. Hsü, K. J. (1975) Catastrophic debris streams (sturzstrwms) generated by rockfalls. Bull. geol. Soc. Am., 86, 129–140.
    [Google Scholar]
  27. Hubbert, M. K. & Rubey, W. W. (1959) Role of fluid pressure in the mechanics of overthrust faulting I: Mechanics of fluid‐filled porous solids and its application to overthrust faulting. Bull. geol. Soc. Am., 70, 115–166.
    [Google Scholar]
  28. Jackson, J. A. (1987) Active normal faulting and crustal extension. In: Continental Extensional Tectonics (Ed. by M. P.Coward, J. F.Dewey and P. L.Hancock). Spec. Pap. geol. Soc. London. 28, 3–17.
  29. John, B. E. (1987) Geometry and evolution of a mid‐crustal extensional fault system: Chemehuevi Mountains, southeastern California. In: Continental Extensional Tectonics (Ed. by M. P.Coward, J. F.Dewey and P. L.Hancock). Spec. Pap. geol. Soc. London. 28, 313–335.
  30. Kent, P. E. (1966) The transport mechanism in catastrophic rock falls. J. Geol., 74, 79–83.
    [Google Scholar]
  31. Melosh, H. J. (1986) The physics of very large landslides. Acta Mech., 64, 89–99.
    [Google Scholar]
  32. Miller, J. M. G. & John, B. E. (1988) Detached strata in a Tertiary low‐angle normal fault terrane, southeastern California: a sedimentary record of unroofing, breaching, and continued slip. Geology, 16, 645–648.
    [Google Scholar]
  33. Nielson, J. E. & Beratan, K. K. (1990) Tertiary basin development and tectonic implications, Whipple detachment system, Colorado River extensional corridor, California and Arizona. J. geophy. Res., 95, 599–614.
    [Google Scholar]
  34. Parke, M. & Davis, G. A. (1990) Gravity gliding in the eastern Mojave Desert? Only the Shadows know. Geol. Soc. Am. Abstracts with Programs, 22, 74.
    [Google Scholar]
  35. Phillips, J. (1982) Character and origin of cataclasite developed along the low‐angle Whipple detachment fault, Whipple Mountains, California. In: Mesozoic—Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona and Nevada (Ed. by E. G.Frost and D. L.Martin ). pp. 109–116.Cordilleran Publishers, San Diego .
    [Google Scholar]
  36. Reynolds, S. J. & Lister, G. S. (1987) Structural aspects of fluid‐rock interactions in detachment zones. Geology, 15, 362–366.
    [Google Scholar]
  37. Ridenour, J., Moyle, P. R. & Willett, S. L. (1982) Mineral occurrences in the Whipple Mountains wilderness study area, San Bernardino County, California. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona and Nevada (Ed. E. G.Frost and D. L.Martin ), pp. 69–74. Cordilleran Publishers, San Diego .
    [Google Scholar]
  38. Roberts, P. (1992) Miocene basin evolution in the upper plate of the Whipple detachment fault, southwestern Arizona. MS thesis, Flagstaff , Northern Arizona University.
  39. Shakal, A., Huang, M., Darragh, R.Cao, T., Sherburne, K., Malhotra, P., Cramer, C., Sudnor, R., Grazier, V., Maldonado, G., Petersen, C. & Wamrole, J., (1994) CSMIP strong‐motion records from the Northridge, California earthquake of 17 January 1994. California Department of Conservation, Report No. OSMS 94–07.
  40. Shreve, R. L. (1968a) The Blackhawk landslide. Spec. Pap. geol. Soc. Am. 108.
    [Google Scholar]
  41. Shreve, R. L. (1968b) Leakage and fluidization in air‐layer lubricated avalanches. Bull. geol. Sol. Am.. 79, 653–658.
    [Google Scholar]
  42. Spencer, J. E. (1982) Origin of folds of Tertiary low‐angle fault surfaces, southeastern California and western Arizona. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona and Nevada (Ed. by E. G.Frost and D. L.Martin ), pp. 123–134. Cordilleran Publishers, San Diego .
    [Google Scholar]
  43. Teel, D. B. & Frost, E. G. (1982) Synorogenic evolution of the Copper Basin Formation in the eastern Whipplc Mountains, San Bernardino County, California. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona and Nevada (Ed. by E. G.Frost and D. L.Martin ), pp. 275–285. Cordilleran Publishers, San Diego .
    [Google Scholar]
  44. Wilkins, J. & Heidrick, T. L. (1982) Base and precious metal mineralization related to low‐angle tectonic features in the Whipple Mountains, California and Buckskin Mountains, Arizona. In: Mesozoic‐Cenozoic Tectonic Evolution of the Colorado River Region, California, Arizona and Nevada (Ed. by E. G.Frost and D. L.Martin ), pp. 182–202. Cordilleran Publishers, San Diego .
    [Google Scholar]
  45. Wernicke, B. & Burchfiel, B. C. (1982) Modes of extensional tectonics. J. struct. Geol., 4, 105–115.
    [Google Scholar]
  46. Xiao, H. & Suppe, J. (1992) Origin of rollover. Bull. Am. Ass. petrol. Geol., 76, 509–529.
    [Google Scholar]
  47. Yarnold, J. C. (1993) Rock avalanche characteristics in dry climates and the effect of flow into lakes: insights from mid‐Tertiary sedimentary breccias near Artillery Peak, Arizona. Bull. geol. Sol. Am., 105, 345–360.
    [Google Scholar]
  48. Yarnold, J. C. & Lombard, J. P. (1989) A facies model for large rock‐avalanche deposits formed in dry climates. In. Conglomerates in Basin Analysis: A Symposium Dedicated to A. O. Woodford (Ed. by I. P.Colburn, P. L.Abbott and J.Minch). Pacific Section Soc. econ. Paleont. Miner. 62, 9–31.
  49. Yin, A. (1991) Mechanisms for the formation of domal and basinal detachment faults: A three‐dimensional analysis. J. geophys. Res., 96, 14,577–14,594.
    [Google Scholar]
  50. Yin, A. & Dunn, J. F. (1992) Structural and stratigraphic development of the Whipple‐Chemehuevi detachment‐fault system, southeastern California: implications for the geometrical evolution of domal and basinal low‐angle normal faults. Bull. pol. Soc. Am., 104, 659–674.
    [Google Scholar]
  51. Yin, A. (1994) Mechanics of wedge‐shaped fault blocks 2. An elastic solution for extensional wedges. J. geophy. Res., 99, 7045–7055.
    [Google Scholar]
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