Chihuahua trough—A Jurassic pull-apart basin
Walter T. Haenggi, William R. Muehlberger, 2005. "Chihuahua trough—A Jurassic pull-apart basin", The Mojave-Sonora Megashear Hypothesis: Development, Assessment, and Alternatives, Thomas H. Anderson, Jonathan A. Nourse, James W. McKee, Maureen B. Steiner
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The Chihuahua trough is a right-lateral pull-apart basin that began to form ca. 159 to ca. 156 Ma (Oxfordian) during a period of relative counterclockwise rotation of the North American plate. The Chihuahua trough developed as a right step between two right-lateral fault systems—the Texas “zone” and the San Marcos fault zone, which has been interpreted as an element of the Mojave-Sonora megashear. By this interpretation, the Mojave-Sonora fault zone of the Caborca area cannot—and need not—be projected to join the San Marcos fault zone as a continuous system in medial Jurassic time.
Jurassic seas were well established by latest Oxfordian time, and there was little change in basin configuration throughout the remainder of Late Jurassic and Early Cretaceous time. Elements of a broad zone of intersecting preexisting northwest-trending and north-trending structures along the southwest border of the North American craton provide the fabric for development of the pull-apart basin between the Diablo and Aldama platforms. While the presence of Middle to Upper Jurassic marine rocks in Chihuahua and Sonora has received comment in previous articles, this paper provides a regionally consistent tectonic mechanism for creating two arms of the Mar Mexicano.