105,149 research outputs found
(Table 1) Lithium concentration and isotopic composition of rocks from ODP Hole 148-896A
No full textSr and d18O data see Teagle et al. (1996) datasets: doi:10.1594/PANGAEA.71342
(Table 1) Strontium concentrations and isotope ratios of anhydrite from DSDP/ODP Hole 504B
No full textIn samples from 1575 to 1982 mbsf anhydrite leached from whole-rock powders. 87Sr/86Sr and Sr/Ca determined following methods described in (Teagle et al., 1996, doi:10.2973/odp.proc.sr.148.113.1996, Teagle et al., 1998, doi:10.2973/odp.proc.sr.158.223.1998). For the period of the analysis (Jan. 1994-Dec. 1995) NIST SRM 987 gave 87Sr/86Srs0.710244 +/- 0.000018 (2 sigma, n = 115). Full analytical procedural blanks were <50 pg for Sr. delta18O following (Pickthorn and O´Neil, 1985). Repeated extractions and measurements of samples and standards were reproducible within +/- 0.5
"The Educational Value of the College Fed Challenge"
No full textThe College Fed Challenge, a competition between undergraduate students from different colleges and universities, is designed to enhance the development of research, critical thinking, and presentation skills. This paper analyzes the value of the competition as an instrument for improving undergraduate economics education. We present results from surveys of (a) students who participated in one district in November 2010 and (b) graduates from the University of Delaware who participated in past years. The results reflect the impressive effect on student learning outcomes. We conclude that the visibility of the College Fed Challenge can be an important factor in determining its impact and that the competition could conceivably have a significant and positive impact on economics education in the United States.economic education, undergraduate economics, education environment, experienced based education
Lithium and lithium isotope profiles through the upper oceanic crust: a study of seawater-basalt exchange at ODP Sites 504B and 896A
No full textOcean Drilling Program (ODP) Hole 504B near the Costa Rica Rift is the deepest hole drilled in the ocean crust, penetrating a volcanic section, a transition zone and a sheeted dike complex. The distribution of Li and its isotopes through this 1.8-km section of oceanic crust reflects the varying conditions of seawater alteration with depth. The upper volcanic rocks, altered at low temperatures, are enriched in Li (5.6–27.3 ppm) and have heavier isotopic compositions (7Li=6.6–20.8‰) relative to fresh mid-ocean ridge basalt (MORB) due to uptake of seawater Li into alteration clays. The Li content and isotopic compositions of the deeper volcanic rocks are similar to MORB, reflecting restricted seawater circulation in this section. The transition zone is a region of mixing of seawater with upwelling hydrothermal fluids and sulfide mineralization. Li enrichment in this zone is accompanied by relatively light isotopic compositions (?0.8–2.1‰) which signify influence of basalt-derived Li during mineralization and alteration. Li decreases with depth to 0.6 ppm in the sheeted dike complex as a result of increasing hydrothermal extraction in the high-temperature reaction zone. Rocks in the dike complex have variable isotopic values that range from ?1.7 to 7.9‰, depending on the extent of hydrothermal recrystallization and off-axis low-temperature alteration. Hydrothermally altered rocks are isotopically light because 6Li is preferentially retained in greenschist and amphibolite facies minerals. The 7Li values of the highly altered rocks of the dike complex are complementary to those of high-temperature mid-ocean ridge vent fluids and compatible to equilibrium control by the alteration mineral assemblage. The inventory of Li in basement rocks permits a reevaluation of the role of oceanic crust in the budget of Li in the ocean. On balance, the upper 1.8 km of oceanic crusts remains a sink for oceanic Li. The observations at 504B and an estimated flux from the underlying 0.5 km of gabbro suggest that the global hydrothermal flux is at most 8×109 mol/yr, compatible with geophysical thermal models. This work defines the distribution of Li and its isotopes in the upper ocean crust and provides a basis to interpret the contribution of subducted lithosphere to arc magmas and cycling of crustal material in the deep mantle
Hydration Maps of Oman Drilling Project Holes GT1A, GT2A, and GT3A
No full textThis dataset is the supplement for the following paper: Crotteau, M.A., Greenberger, R. N., Ehlmann, B. L., Rossman, G.R., Harris, M., Kelemen, P. B., Teagle, D. A. H., et al. (2021). Characterizing Hydration of the Ocean Crust Using Shortwave Infrared Microimaging Spectroscopy of ICDP Oman Drilling Project Cores. Journal of Geophysical Research: Solid Earth. These datasets are maps of hydration for the International Continental Scientific Drilling Program (ICDP) Oman Drilling Project (OmanDP) Holes GT1A, GT2A, and GT3A. The maps were derived from imaging spectroscopy measurements of the archive half of the OmanDP cores, with methods for data acquisition described in Kelemen et al. (2020) and data analysis in Crotteau et al. (2021). The hydration maps archived here are part of the supplement of Crotteau et al. (2021) but are too large to be published through the journal. Data descriptions are in the supplement of Crotteau et al. (2021), and that paper must be cited with use of these datasets. Included files: 1. GT1A_HydrationMaps.pdf: Maps of the hydration in Hole GT1A. 2. GT2A_HydrationMaps.pdf: Maps of the hydration in Hole GT2A. 3. GT3A_HydrationMaps.pdf: Maps of the hydration in Hole GT3A.,
Cite this record as:
Crotteau, M. A., Greenberger, R. N., Ehlmann, B. L., Rossman, G. R., Harris, M., Kelemen, P. B., Teagle, D. A. H., &amp; Team, T. O. D. P. S. (2021). Hydration Maps of Oman Drilling Project Holes GT1A, GT2A, and GT3A (Version 1.0) [Data set]. CaltechDATA. https://doi.org/10.22002/D1.2141
or choose a different citation style.
Download Citation
,</span
Hydration Imaging Spectroscopy Dataset for Oman Drilling Project Holes GT1A, GT2A, and GT3A
No full textThis dataset contains paired .img and .hdr files of calculated water content used for the following paper: Crotteau, M.A., Greenberger, R. N., Ehlmann, B. L., Rossman, G.R., Harris, M., Kelemen, P. B., Teagle, D. A. H., et al. (2021). Characterizing Hydration of the Ocean Crust Using Shortwave Infrared Microimaging Spectroscopy of ICDP Oman Drilling Project Cores. Journal of Geophysical Research: Solid Earth. This dataset contains the .img and .hdr files with weight percent water values for each pixel for the International Continental Scientific Drilling Program (ICDP) Oman Drilling Project (OmanDP) Holes GT1A, GT2A, and GT3A. The hydration values were derived from imaging spectroscopy measurements of the archive half of the OmanDP cores, with methods for data acquisition described in Kelemen et al. (2020) and data analysis in Crotteau et al. (2021). Data descriptions are in the supplement of Crotteau et al. (2021), and that paper must be cited with use of this dataset. Included files: 1. GT1A_HydrationMaps.zip: Zip file containing paired .img and .hdr files containing calcuated hydration for each core section in Hole GT1A. 2. GT2A_HydrationMaps.zip: Zip file containing paired .img and .hdr files containing calcuated hydration for each core section in Hole GT2A. 3. GT3A_HydrationMaps.zip: Zip file containing paired .img and .hdr files containing calcuated hydration for each core section in Hole GT3A.,
Cite this record as:
Crotteau, M. A., Greenberger, R. N., Ehlmann, B. L., Rossman, G. R., Harris, M., Kelemen, P. B., Teagle, D. A. H., &amp; Team, T. O. D. P. S. (2021). Hydration Imaging Spectroscopy Dataset for Oman Drilling Project Holes GT1A, GT2A, and GT3A (Version 1.0) [Data set]. CaltechDATA. https://doi.org/10.22002/D1.2142
or choose a different citation style.
Download Citation
,</span
Determination of ultra-trace Au, Ag, As, Pt and Re mass fractions in volcanic glasses and rock powders by LA-ICP-MS
No full textPractical methods for determining the ultra-trace abundances of precious metals in geological materials are needed for research into magmatic and hydrothermal processes and to expand the geochemical footprints of concealed ore deposits. This study presents a new protocol for determining Au, Ag, As, Pt and Re mass fractions in both volcanic glasses and in rock powders prepared as nano-powder pellets, through the synthesis and refinement of published LA-ICP-MS methods. This matrix flexibility allows the method and its limitations to be rigorously assessed for the first time using different volcanic materials. High-yield laser parameters, interference corrections and low oxide production rates facilitated by laser ablation sampling enabled accurate measurements without chemical pre-separation. A key finding is that ablation-remobilised system contamination must be quantified and corrected to make accurate ng g−1-level Au determinations by LA-ICP-MS, resulting in a mean + 2s quantification limit for Au of 0.38 ng g−1. This approach is likely necessary for other ultra-trace LA-ICP-MS analyses of certain elements. Following this correction, the protocol can be usefully applied to both in situ analysis of volcanic materials and efficiently integrated into methods for the determination of major and trace elements in nano-powder pellets
Constraining uncertainty in boron isotope systematics using a Bayesian inversion engine reveals contrasting parameter sensitivities
No full textPhysical parameters within boron isotope systematics form a complex interplay that determine the boron isotopic composition of rocks, minerals, and fluids, but to date, providing constraints on uncertainty within boron equilibrium isotope modelling remains elusive. This underlying uncertainty limits the potency of boron isotopes as a tool for detecting fluid-rock exchange. A new equilibrium boron mineral-fluid fractionation modelling approach, named EquiB, coupled with a Bayesian inversion engine is presented, providing robust and reproducible constraints on the uncertainty of physical parameters encoded into a boron isotopic composition of a rock in equilibrium with a fluid. We demonstrate the validity of our approach by applying the model to several basalt-fluid and peridotite-fluid exchange scenarios. The model output generates multi-dimensional posterior probability distributions that show temperature is the greatest control on mineral-fluid fractionation in all applied scenarios. At high temperatures (defined as >50 °C) pH-dependent fractionation is negligible, but at low temperatures (defined as <50 °C) pH-dependent fractionation is a control on boron isotopic compositions. At geologically reasonable conditions other parameters such as salinity, fluid density, and pressure have little effect on the extent of boron mineral-fluid fractionation. Model outputs agree with experimentally derived fractionation factors at typical hydrothermal conditions but diverge at low temperatures. This approach provides robust constraints of parameter uncertainty, enabling meaningful interpretation of boron isotope analyses and the ability to fingerprint isotopic compositions with greater confidence.</p
Mineral occurrence maps of Oman Drilling Project Holes GT1A, GT2A, and GT3A
No full textThese datasets are maps of the occurrences of key minerals and mineral groups (clinopyroxene, amphibole, chlorite, epidote, prehnite, zeolite, gypsum, calcite, and kaolinite/montmorillonite) for the International Continental Scientific Drilling Program (ICDP) Oman Drilling Project (OmanDP) Holes GT1A, GT2A, and GT3A. The maps were derived from imaging spectroscopy measurements of the archive half of the OmanDP cores, with methods for data acquisition described in Kelemen et al. (2020) and data analysis in Greenberger et al. (in review, JGR Solid Earth). The mineral occurrence maps archived here are part of the supplement of Greenberger et al. (in review) but are too large to be published through the journal. Data descriptions are in the supplement of Greenberger et al. (in review), and that paper must be cited with use of these datasets. Included files: 1. GT1A_MineralOccurrenceMaps.pdf: Maps of the occurrence of key minerals and mineral groups in Hole GT1A. 2. GT2A_MineralOccurrenceMaps.pdf: Maps of the occurrence of key minerals and mineral groups in Hole GT2A. 3. GT3A_MineralOccurrenceMaps.pdf: Maps of the occurrence of key minerals and mineral groups in Hole GT3A.,
Cite this record as:
Greenberger, R. N., Harris, M., Ehlmann, B. L., Crotteau, M., Kelemen, P. B., Manning, C. E., Teagle, D. A. H., &amp; Team, T. O. D. P. S. (2021). Mineral occurrence maps of Oman Drilling Project Holes GT1A, GT2A, and GT3A (Version 1.0) [Data set]. CaltechDATA. https://doi.org/10.22002/D1.2010
or choose a different citation style.
Download Citation
,
Unique Views: 7
Unique Downloads: 0
between June 23, 2021 and July 12, 2021
More info on how stats are collected
,</span
- …
