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Full-Text Articles in Geology
Reply To Simon And Reed: Independent And Converging Results Rule Out Historic Disturbance And Confirm Age Constraints For Barrier Canyon Rock Art, Joel L. Pederson, Harriet Cornachione, Steven R. Simms, Reza Sohbati, Tammy M. Rittenour, Andrew S. Murray, Gary Cox
Reply To Simon And Reed: Independent And Converging Results Rule Out Historic Disturbance And Confirm Age Constraints For Barrier Canyon Rock Art, Joel L. Pederson, Harriet Cornachione, Steven R. Simms, Reza Sohbati, Tammy M. Rittenour, Andrew S. Murray, Gary Cox
Geosciences Faculty Publications
We welcome this further discussion of our results on the age of the Great Gallery rock art in the Canyonlands of Utah. The comment by Simon and Reed (1) focuses on just one of the three components of our study (2), which is presented in greater technical detail in ref. 3 and is surely our best-constrained and least-surprising result: the dating of a rock-fall that removed some of the art and thus provides a minimum age. Simon and Reed (1) point out that the Great Gallery panel is not pristine and relate the sordid human history of visitation and possible …
Drilling The Solid Earth: Global Geodynamic Cycles And Earth Evolution, John W. Shervais, Nicholas Arndt, Kathryn M. Goodenough
Drilling The Solid Earth: Global Geodynamic Cycles And Earth Evolution, John W. Shervais, Nicholas Arndt, Kathryn M. Goodenough
Geosciences Faculty Publications
The physical and chemical evolution of the Earth is driven by geodynamic cycles that are global in scale, operating over 4.57 Ga of Earth’s history. Some processes are truly cyclic, e.g., the Wilson Cycle, while others are irreversible (e.g., core formation). Heat and mass transfer between the lowermost mantle (e.g., core-mantle boundary) and the surface drives these global geodynamic processes. Subduction of lithospheric plates transfers cool fractionated material into the lower mantle and leads indirectly to the formation of new oceanic lithosphere, while the rise of thermochemical plumes recycles the remnants of these plates back to the surface, driven by …
Age Of Barrier Canyon-Style Rock Art Constrained By Cross-Cutting Relations And Luminescence Dating Techniques, Joel L. Pederson, Harriet Cornachione, Steven R. Simms, Reza Sohbati, Tammy M. Rittenour, Andrew S. Murray, Gary Cox
Age Of Barrier Canyon-Style Rock Art Constrained By Cross-Cutting Relations And Luminescence Dating Techniques, Joel L. Pederson, Harriet Cornachione, Steven R. Simms, Reza Sohbati, Tammy M. Rittenour, Andrew S. Murray, Gary Cox
Geosciences Faculty Publications
Rock art compels interest from both researchers and a broader public, inspiring many hypotheses about its cultural origin and meaning, but it is notoriously difficult to date numerically. Barrier Canyon-style (BCS) pictographs of the Colorado Plateau are among the most debated examples; hypotheses about its age span the entire Holocene epoch and previous attempts at direct radiocarbon dating have failed. We provide multiple age constraints through the use of cross-cutting relations and new and broadly applicable approaches in optically stimulated luminescence dating at the Great Gallery panel, the type section of BCS art in Canyonlands National Park, southeastern Utah. Alluvial …
Composition, Alteration, And Texture Of Fault-Related Rocks From Safod Core And Surface Outcrop Analogs: Evidence For Deformation Processes And Fluid-Rock Interactions, Kelly Keighley Bradbury, Colter R. Davis, John W. Shervais, Susanne U. Janecke, James P. Evans
Composition, Alteration, And Texture Of Fault-Related Rocks From Safod Core And Surface Outcrop Analogs: Evidence For Deformation Processes And Fluid-Rock Interactions, Kelly Keighley Bradbury, Colter R. Davis, John W. Shervais, Susanne U. Janecke, James P. Evans
Geosciences Faculty Publications
We examine the fine-scale variations in mineralogical composition, geochemical alteration, and texture of the fault-related rocks from the Phase 3 whole-rock core sampled between 3,187.4 and 3,301.4 m measured depth within the San Andreas Fault Observatory at Depth (SAFOD) borehole near Parkfield, California. This work provides insight into the physical and chemical properties, structural architecture, and fluid-rock interactions associated with the actively deforming traces of the San Andreas Fault zone at depth. Exhumed outcrops within the SAF system comprised of serpentinite-bearing protolith are examined for comparison at San Simeon, Goat Rock State Park, and Nelson Creek, California. In the Phase …
Late Quaternary Faulting History Of The Carrizal And Related Faults, La Paz Region, Baja California Sur, Mexico, Paul J. Umhoefer, Sara J. Maloney, Beverly Buchanan, J. Ramón Arrowsmith, Genaro Martinez-Gutiérrez, Graham Kent, Neal Driscoll, Alistair Harding, Darrell Kaufman, Tammy M. Rittenour
Late Quaternary Faulting History Of The Carrizal And Related Faults, La Paz Region, Baja California Sur, Mexico, Paul J. Umhoefer, Sara J. Maloney, Beverly Buchanan, J. Ramón Arrowsmith, Genaro Martinez-Gutiérrez, Graham Kent, Neal Driscoll, Alistair Harding, Darrell Kaufman, Tammy M. Rittenour
Geosciences Faculty Publications
The southwest margin of the Gulf of California has an array of active normal faults despite this being an oblique-divergent plate boundary with spreading centers that localized deformation along the plate boundary 2–3 million years ago. The Carrizal and Centenario faults form the western border fault of the Gulf of California marginal fault system within and south of La Paz Bay, and ∼20–30 km west of the capital city of La Paz, Baja California Sur, Mexico. Geologic and geomorphic mapping, optically stimulated luminescence (OSL) geochronology, and paleoseismic investigations onshore, compressed high-intensity radar pulse (CHIRP) profiling offshore, and analysis of uplifted …