A5075046514- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- earthquake and tectonic studies
- Geochemistry and Geologic Mapping
- Hydrocarbon exploration and reservoir analysis
- Advanced X-ray and CT Imaging
- Planetary Science and Exploration
- Astro and Planetary Science
- Nuclear materials and radiation effects
- Geological and Tectonic Studies in Latin America
- Nuclear Physics and Applications
- Medical Imaging Techniques and Applications
- Seismic Imaging and Inversion Techniques
- Geology and Paleoclimatology Research
- Evolution and Paleontology Studies
- Groundwater flow and contamination studies
- Nuclear Materials and Properties
- Paleontology and Evolutionary Biology
- Hydraulic Fracturing and Reservoir Analysis
- Pleistocene-Era Hominins and Archaeology
- Space Exploration and Technology
- Mineral Processing and Grinding
- Methane Hydrates and Related Phenomena
- Primate Behavior and Ecology
- Radioactive element chemistry and processing
The University of Texas at Austin
2016-2025
The University of Melbourne
2021
Syracuse University
2007-2008
General Electric (United States)
2007
Georgia College & State University
2006
Arizona State University
2006
Natural History Museum
2006
Williams College
1988
University of California, Riverside
1971-1973
Research Article| January 01, 2005 Forward and Inverse Modeling of Low-Temperature Thermochronometry Data Richard A. Ketcham Jackson School Geosciences, The University Texas at Austin, Texas, 78712, U.S.A., ketcham@mail.utexas.edu Search for other works by this author on: GSW Google Scholar Reviews in Mineralogy Geochemistry (2005) 58 (1): 275–314. https://doi.org/10.2138/rmg.2005.58.11 Article history first online: 03 Mar 2017 Cite View This Citation Add to Manager Share Icon Facebook...
Two abiding issues impact the reliability of apatite fission-track analysis and thermal history inversion in particular: reproducibility track-length measurements variability annealing kinetics. In companion to this paper, we addressed first by demonstrating that using c-axis projection normalize track lengths for crystallographic angle improves among acquired Barbarand et al. (2003a, 2003b). We continue here looking at effect on extrapolation laboratory geological time scales. find...
A new model for examining fission-track data from natural specimens has been developed on the basis of laboratory describing annealing in a wide variety apatites and empirical correction length anisotropy presented earlier papers. Using revised simplified statistical methods, we examine how well various equations are able to fit reproduce expected behavior geological time scales. Based latter criterion, find that so-called “fanning Arrhenius” models mean track not bestsuited our data....
Accurate thermochronologic interpretation of zircon (U-Th)/He dates requires a realistic and practically useful understanding He diffusion kinetics in natural zircon, ideally across the range variation that characterize typically dated specimens. Here we present series date measurements document importance alpha dose, which interpret to be correlated with accumulated radiation damage, on diffusivity. This effect is manifest both date-effective uranium (eU) correlations among grains from...
Research Article| January 01, 2005 Apatite Fission-Track Analysis Raymond A. Donelick; Donelick to Zircon, Inc., 1075 Matson Road, Viola, Idaho 83872-9709, U.S.A., Department of Geological Sciences, University Nevada-Reno, Reno, Nevada 89557-0138, donelick@apatite.com Search for other works by this author on: GSW Google Scholar Paul B. O’Sullivan; O’Sullivan Idaho, Moscow, 83844-3022, U.S.A. Richard Ketcham Jackson School Geosciences, Texas at Austin Austin, Texas, 78712-0254, Author and...
Annealing rates for fission tracks in apatite vary markedly as a complex function of composition, based on an experimental study 15 well-characterized, compositionally diverse apatites. Extensive annealing data were obtained 69 experiments (durations 1, 10, 100, and 1000 h at temperatures from 75 to 400 °C) each four apatites, three with near end-member occupancy the halogen site by F, Cl, OH, plus well-known Durango, Mexico. These results supplemented less-comprehensive 12 over same range...
A method is presented that permits the length of any horizontal, confined fission-track inclined at a specified angle to crystallographic c axis in apatite be converted an equivalent track parallel axis. The model based on results annealing experiments for six selected apatites (five calcian fluorapatites and Durango apatite) representing subset 15 total specimens studied. An iterative process calculation required project lengths onto computer source code implementing solution this problem...
Volumetric imaging techniques, such as high-resolution X-ray computed tomography, allow three-dimensional measurements of discrete objects inside solid samples. This paper introduces a new computer program called BLOB3D that is designed to efficient measurement up thousands features in single sample, porphyroblasts, sediment grains, clasts, and voids. implements an original suite software methods, divided into three modules, which respectively enable the tasks segmenting those regions data...
Apatite fission-track length data are used extensively for thermal history inversion. However, several studies have documented instances of poor reproducibility data. We address this problem by using c-axis projection to normalize track lengths crystallographic angle in the extensive laboratory annealing set acquired Barbarand et al. (2003a, 2003b). A new simplification reduces model from six four fitted parameters. Normalizing improves every aspect measurement examined. It accelerates...
Macroscopic textures resulting from different atomic‐scale mechanisms for metamorphic crystallization display degrees of order, clustering, intergrowth and relative isolation porphyroblasts. Data on the sizes locations thousands crystals in a three‐dimensional volume are required to identify reliably governing nucleation growth porphyroblasts these textural features. These data can now be acquired by means high‐resolution computed X‐ray tomography. Numerical models that simulate...
Research Article| January 01, 2005 Computational Tools for Low-Temperature Thermochronometer Interpretation Todd A. Ehlers; Ehlers Department of Geological Sciences, University Michigan, Ann Arbor, 48109-1005, U.S.A., tehlers@umich.edu Search other works by this author on: GSW Google Scholar Tehmasp Chaudhri; Chaudhri Santosh Kumar; Kumar Chris W. Fuller; Fuller Earth and Space Washington, Seattle, 98195, U.S.A. Sean D. Willett; Willett Richard Ketcham; Ketcham Jackson School Geosciences,...
Summary A number of methods for measuring anisotropy in trabecular bone using high‐resolution X‐ray computed tomography exist, which give different answers but have not been compared detail. In this study, we examine the mean‐intercept length (MIL), star volume distribution (SVD) and (SLD) methods, their algorithmic implementation three‐dimensional (3D) data, how results relate to each other. uniform ordered sampling scheme determining orientations sample during analysis enhances...
Abstract The classical Local Cubic Law (LCL) generally overestimates flow through real fractures. We thus developed and tested a modified LCL (MLCL) which takes into account local tortuosity roughness, works across low range of Reynolds Numbers. MLCL is based on (1) modifying the aperture field by orienting it with direction (2) correcting for roughness changes associated expansion/contraction. In order to test MLCL, we compared direct numerical simulations Navier‐Stokes equations using...
Abstract The capillary trapping of supercritical CO 2 (s‐CO ) is postulated to comprise up 90% permanently trapped injected during geologic sequestration. Successive s‐CO /brine flooding experiments under reservoir conditions showed that water‐wet rounded beads 15% both as clusters and individual ganglia, whereas ‐wet only 2% the minute pockets in pore constrictions. Angular grains 20% but flow was affected by preferential flow. Thus, a viable mechanism for permanent storage, its success...
Previously unreleased fission-track results and regional structural relationships are used to interpret the migration of deformation during Cenozoic orogenesis in Eastern Cordillera (Cordillera Oriental) Colombian Andes. Low-temperature thermochronological based on apatite zircon analyses 41 samples collected along vertical horizontal transects across at 4–7N latitude. Inverse modeling helps delimit most probable cooling histories caused by exhumation linked upper-crustal deformation. These...