s a fundamental role in localizing rift-related faulting and the process of continental rupture. The Gulf of California Shear Zone developed as a continuation of the southern San Andreas fault system and directly preceded the formation of the Gulf of California about 6 to 7 million years ago, via northwesterly oblique motion of Baja California away from mainland Mexico. New, high-precision paleomagnetic data from two extensive pyroclastic flow deposits, erupted from within the rift, show that approximately half (locally 0 to 75%) of clockwise vertical- axis rotation associated with the Gulf of California Shear Zone began prior to localization of rifting. Rotations are highest near the Baja California and Sonora shorelines, which constitute displaced fragments of the Gulf of California Shear Zone. This is consistent with independent geologic studies that suggest shear- zone faulting and block rotation initiated about 9-8 million years ago and plate tectonic studies that document an increase in rift obliquity about 8 million years ago.
Dominance of tectonics over climate in Himalayan denudation
Vincent Godard et al., Aix-Marseille Universit, CNRS, IRD, CEREGE UM34, 13545 Aix-en-Provence, France; firstname.lastname@example.org. Posted online 10 January 2014, http://dx.doi.org/10.1130/G35342.1.
Denudation of continents is under the control of tectonic processes building topographic relief and precipitation providing water to erode the surface. However, the relative importance of these two factors is still a matter of debate, in particular in mountain ranges, where some studies have proposed that local high precipitation could focus denudation, which might affect underlying tectonic deformation. In this study we present a new dataset of denudation rates for the Himalayas of Nepal derived from measurements of rare isotopes (10Be) in riverPage: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Related biology news :1
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