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Selected Works of Bernard A. Housen
Presentation
Magnetostratigraphy and Paleocurrent Directions for the Upper Member of the Palm Spring Formation, Mecca Hills, CA
2013 American Geophysical Union (AGU) Fall Meeting (2013)
  • G. T. Messe, Western Washington University
  • B. A. Housen, Western Washington University
  • R. F. Burmester, Western Washington University
  • J. C. McNabb, University of Oregon
  • R. J. Dorsey, University of Oregon
Link
Abstract
Ongoing paleomagnetic analysis of the Plio-Pleistocene Palm Spring Formation of the Mecca Hills, CA provides insight into the development and sedimentation of transtensional basins in the San Andreas fault zone. Samples have a mixture of demagnetization behavior- roughly half the samples and sites have well-defined magnetization components that allow for best-fit lines to be identified, while the other set of samples and sites have curvilinear trends, so a combined line-and-plane analysis was used to determine their characteristic directions. In the upper section of Painted Canyon, samples collected and analyzed thus far yield four well-defined polarity zones in the upper member of the Palm Spring Formation. Interpretation of the polarity zones suggests that the section spans most of the Matuyama chron, including the Jaramillo and the Brunhes-Matuyama boundary. The upper member of the Palm Spring Formation is likely younger than 1.79 Ma (the termination of the Olduvai). Preliminary interpretation of measured anisotropy of magnetic susceptibility (AMS) provides sediment transport/paleocurrent direction from several of the sites, based on the interpretation methods detailed by Tarling and Hrouda (1993) and Tauxe (1998). Plots of minimum, intermediate and maximum susceptibility axes on equal area projections indicate variation of depositional settings through time, represented by the variation in susceptibility axes alignment. Substantial differences are observed between sediment types, with specimens from the two siltiest sites having the most well-defined AMS axis directions. First order analysis of AMS is consistent with a SW paleocurrent direction for the top two sites, a SE or NW paleocurrent direction for mid-section sites and SW or NE paleocurrent direction for lower sites. This interpretation is reasonable considering the provenance and transport direction of the sediments, inferred by McNabb et al. (this meeting). Alternatively, some of the AMS results may be records of magnetic fabric from syntectonic sedimentation deformation. This alternate hypothesis will be explored further in future analysis. References: Tarling, D.H. and Hrouda, F, 1993, The magnetic anisotropy of rocks, Chapman and Hall Tauxe, Lisa, 1998, Modern approaches in geophysics: Paleomagnetic Principles and Practice, Kluwer Academic Publishers.
Keywords
  • Paleomagnetic analysis,
  • Demagnetization
Disciplines
Publication Date
December 1, 2013
Location
San Francisco
Citation Information
G. T. Messe, B. A. Housen, R. F. Burmester, J. C. McNabb, et al.. "Magnetostratigraphy and Paleocurrent Directions for the Upper Member of the Palm Spring Formation, Mecca Hills, CA" 2013 American Geophysical Union (AGU) Fall Meeting (2013)
Available at: http://works.bepress.com/bernard_housen/83/