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Download or read book Testing the Structural Role of the Santa Maria Basin in the Rotation of the Western Transverse Ranges, California and the Magnetostratigraphy of the McDonald Shale, Temblor Range, California written by Jonathan K. Guillaume and published by . This book was released on 2013 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The Santa Maria Basin (SMB) lies between the rotated Western Transverse Ranges, and the non-rotated Southern Coast Ranges. The goal of this study was to use paleomagnetism to determine if the SMB is rotated or not and the samples were subject to alternating field and thermal demagnetization analysis. Equal area diagrams indicate the samples have a remanence dominated entirely by the present day field, resulting in a failure to answer the main question of the study. Remagnetization probably occurred due to partial oxidation of pyrite to magnetite as the rocks were lifted above sea level during the Pleistocene, causing flushing of the formation with meteoric groundwater. This process is commonly observed in rocks found in fold and thrust belts. A preliminary magnetostratigraphic analysis of the McDonald Shale Member of the Miocene Monterey Formation at Chico Martinez Creek resulted in the identification at least 3 reversals of the ancient geomagnetic field.