Journal ArticleDOI
Pacific-North America Plate Tectonics of the Neogene Southwestern United States: An Update
Tanya Atwater,Joann M. Stock +1 more
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In this paper, the authors use updated rotations within the Pacific-Antarctica-Africa-North America plate circuit to calculate plate reconstructions for times since chron 13 (33 Ma).Abstract:
We use updated rotations within the Pacific-Antarctica-Africa-North America plate circuit to calculate Pacific-North America plate reconstructions for times since chron 13 (33 Ma). The direction of motion of the Pacific plate relative to stable North America was fairly steady between chrons 13 and 4, and then changed and moved in a more northerly direction from chron 4 to the present (8 Ma to the present). No Pliocene changes in Pacific-North America plate motion are resolvable in these data, suggesting that Pliocene changes in deformation style along the boundary were not driven by changes in plate motion. However, the chron 4 change in Pacific-North America plate motion appears to correlate very closely to a change in direction of extension documented between the Sierra Nevada and the Colorado Plateau. Our best solution for the displacement with respect to stable North America of a point on the Pacific plate that is now near the Mendocino triple junction is that from 30 to 12 Ma the point was displaced along an azimuth of ∼N60°W at rate of ∼33 mm/yr; from 12 Ma to about 8 Ma the azimuth of displacement was about the same as previously, but the rate was faster (∼52 mm/yr); and since 8 Ma the point was displaced along an azimuth of N37°W at a rate of ∼52 mm/yr.
We compare plate-circuit reconstructions of the edge of the Pacific plate to continental deformation reconstructions of North American tectonic elements across the Basin and Range province and elsewhere in order to evaluate the relationship of this deformation to the plate motions. The oceanic displacements correspond remarkably well to the continental reconstructions where deformations of the latter have been quantified along a path across the Colorado Plateau and central California. They also supply strong constraints for the deformation budgets of regions to the north and south, in Cascadia and northern Mexico, respectively.
We examine slab-window formation and evolution in a detailed re-analysis of the spreading geometry of the post-Farallon microplates, from 28 to 19 Ma. Development of the slab window seems linked to early Miocene volcanism and deformation in the Mojave Desert, although detailed correlations await clarification of early Miocene reconstructions of the Tehachapi Mountains. We then trace the post-20 Ma motion of the Mendocino slab window edge beneath the Sierran-Great Valley block and find that it drifted steadily north, then stalled just north of Sutter Buttes at ∼4 Ma.read more
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Cenozoic geological and plate tectonic evolution of SE Asia and the SW Pacific: computer-based reconstructions, model and animations
TL;DR: In this article, a model for the Cenozoic development of the region of SE Asia and the SW Pacific is presented and its implications are discussed, accompanied by computer animations in a variety of formats.
Journal ArticleDOI
Geologically current plate motions
TL;DR: MORVEL as discussed by the authors is a new closure-enforced set of angular velocities for the geologically current motions of 25 tectonic plates that collectively occupy 97 per cent of Earth's surface.
Journal ArticleDOI
Mangroves enhance the biomass of coral reef fish communities in the Caribbean.
Peter J. Mumby,Alasdair J. Edwards,J. Ernesto Arias-Gonzalez,Kenyon C. Lindeman,Paul G. Blackwell,Angela Gall,Malgosia I. Gorczynska,Alastair R. Harborne,Claire L. Pescod,Henk Renken,Colette C. C. Wabnitz,Ghislane Llewellyn +11 more
TL;DR: It is shown that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish in reef fish population dynamics.
Journal ArticleDOI
Young tracks of hotspots and current plate velocities
Alice E. Gripp,Richard G. Gordon +1 more
TL;DR: In this paper, the authors investigated plate motions relative to the hotspots over the past 4 to 7 Myr with a goal of determining the shortest time interval over which reliable volcanic propagation rates and segment trends can be estimated.
Journal ArticleDOI
Active foundering of a continental arc root beneath the southern Sierra Nevada in California
TL;DR: Viscous coupling between the crust and mantle is therefore apparently driving present-day surface subsidence.
References
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Journal ArticleDOI
Revised calibration of the geomagnetic polarity timescale for the Late Cretaceous and Cenozoic
Steven C. Cande,Dennis V. Kent +1 more
TL;DR: An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic.
Journal ArticleDOI
Effect of recent revisions to the geomagnetic reversal time scale on estimates of current plate motions
TL;DR: In this article, the optimal recalibration of NUVEL-1 is proposed to multiply the angular velocities by a constant, α, of 0.9562, which is a compromise among slightly different calibrations appropriate for slow, medium, and fast rates of seafloor spreading.
Journal ArticleDOI
Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America
TL;DR: In this paper, the authors examined the history of plate motions between the American and Pacific plates in the late Cenozoic and found that the two plates were fixed with respect to one another until 5 m.y.
Journal ArticleDOI
Marine gravity anomaly from Geosat and ERS 1 satellite altimetry
TL;DR: In this article, a combination of high-density data from the dense mapping phases of Geosat and ERS 1 along with lower-density but higher-accuracy profiles from their repeat orbit phases is used to construct gravity anomalies from the two vertical deflection grids.
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