Quantitative in situ XRD measurement of shock metamorphism in Martian meteorites using lattice strain and strain‐related mosaicity in olivine     

Laura E. Jenkins  Roberta L. Flemming  Phil J. A. McCausland 《Meteoritics & planetary science》2019,54(4):902-918

All Martian meteorites have experienced shock metamorphism to some degree. We quantitatively determined shock‐related strain in olivine crystals to measure shock level and peak shock pressure experienced by five Martian meteorites. Two independent methods employing nondestructive in situ micro X‐ray diffraction (μXRD) are applied, i.e., (1) the lattice strain method, in which the lattice strain value (ε) for each olivine grain is derived from a Williamson–Hall plot using its diffraction pattern (peak width variation with diffraction angle) with reference to a best fit calibration curve of ε values obtained from experimentally shocked olivine grains; (2) the strain‐related mosaicity method, allowing shock stage to be estimated by measuring the streaking along the Debye rings of olivine grain diffraction spots to define their strain‐related mosaic spread, which can then be compared with olivine mosaicity in ordinary chondrites of known shock stage. In this study, both the calculated peak shock pressures and the estimated shock stages for Dar al Gani 476 (45.6 ± 0.6 GPa), Sayh al Uhaymir 005/8 (46.1 ± 2.2 GPa), and Nakhla (18.0 ± 0.6 GPa) compare well with literature values. Formal shock assessments for North West Africa 1068/1110 (53.9 ± 2.1 GPa) and North West Africa 6234 (44.6 ± 3.1 GPa) have not been reported within the literature; however, their calculated peak shock pressures fall within the range of peak shock pressures defining their estimated shock stages. The availability of nondestructive and quantitative μXRD methods to determine shock stage and peak shock pressure from olivine crystals provides a key tool for shock metamorphism analysis.  相似文献   

Three decades of water quality measurements from the Upper Severn experimental catchments at Plynlimon,Wales: an openly accessible data resource for research,modelling, environmental management and education   总被引：1，自引：0，他引：1  

Colin Neal  Brian Reynolds  Dave Norris  James W. Kirchner  Margaret Neal  Phil Rowland  Heather Wickham  Sarah Harman  Linda Armstrong  Darren Sleep  Alan Lawlor  Clive Woods  Bronwen Williams  Matt Fry  Gwen Newton  Dan Wright 《水文研究》2011,25(24):3818-3830

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Redescription of the skull of Saurolophus osborni Brown 1912 (Ornithischia: Hadrosauridae)     

Phil R. Bell 《Cretaceous Research》2011,32(1):30-44

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Geochemical changes during neutralisation of acid mine drainage in a dynamic mountain stream, New Zealand     

Hugh Davies  Paul Weber  Phil Lindsay  Dave Craw  Barrie Peake  James Pope 《Applied Geochemistry》2011,26(12):2121-2133

The Mangatini Stream drains a coal mining area in the mountains of northwestern South Island of New Zealand. Abundant rainfall on pyritic rocks yields acid mine drainage (AMD) to the stream, which flows through a steep gorge at discharges that rapidly increase from <1 to >100 m³/s during frequent rain events. The AMD is treated with finely ground limestone, which is discharged as a slurry at a point in the middle of the gorge. The limestone slurry mixes and reacts with the AMD during flow ∼4 km downstream over ∼12 h. Neutralisation reactions increase stream pH from near 3 (untreated Mangatini Stream water impacted by AMD) to 5–6 in the first 250 m downstream, although mixing is commonly incomplete in this zone. Large stream discharge volumes in rain events dilute the neutralising material input, thus driving the pH back towards 4 downstream of treatment. More complete neutralisation is achieved 4 km downstream, even in major rain events, and pH can rise to >7. Partial neutralisation is sufficient to remove most of the dissolved Fe(III) (typically ∼30 mg/L) from the Mangatini Stream in the first 10 m, and remaining dissolved Fe is essentially all Fe(II), which decreases over time as it oxidises and precipitates. Dissolved Al in the Mangatini Stream (typically ∼50 mg/L) decreases steadily downstream over ∼100 m in the limestone mixing zone. Precipitated Fe and Al form amorphous oxyhydroxides that are transported as suspended solids and deposited on the stream bed with excess limestone in zones of low flow velocity. Dissolved Zn is removed from solution by adsorption to Fe oxyhydroxide when pH reaches ∼5, but dissolved Ni remains in solution despite the neutralisation process. Gypsum precipitation occurs throughout the limestone mixing zone, resulting in at least 30% decrease in dissolved . Minor ettringite forms in the first 100 m, but then probably redissolves. The limestone dosing system is an effective method of neutralising the effects of AMD and removing most dissolved metals in a steep mountain stream with frequent rain events where this dynamic environment places many constraints on treatment options.  相似文献   

The importance of health co-benefits in macroeconomic assessments of UK Greenhouse Gas emission reduction strategies     

Henning Tarp Jensen  Marcus R. Keogh-Brown  Richard D. Smith  Zaid Chalabi  Alan D. Dangour  Mike Davies  Phil Edwards  Tara Garnett  Moshe Givoni  Ulla Griffiths  Ian Hamilton  James Jarrett  Ian Roberts  Paul Wilkinson  James Woodcock  Andy Haines 《Climatic change》2013,119(2):223-237

We employ a single-country dynamically-recursive Computable General Equilibrium model to make health-focussed macroeconomic assessments of three contingent UK Greenhouse Gas (GHG) mitigation strategies, designed to achieve 2030 emission targets as suggested by the UK Committee on Climate Change. In contrast to previous assessment studies, our main focus is on health co-benefits additional to those from reduced local air pollution. We employ a conservative cost-effectiveness methodology with a zero net cost threshold. Our urban transport strategy (with cleaner vehicles and increased active travel) brings important health co-benefits and is likely to be strongly cost-effective; our food and agriculture strategy (based on abatement technologies and reduction in livestock production) brings worthwhile health co-benefits, but is unlikely to eliminate net costs unless new technological measures are included; our household energy efficiency strategy is likely to breakeven only over the long term after the investment programme has ceased (beyond our 20 year time horizon). We conclude that UK policy makers will, most likely, have to adopt elements which involve initial net societal costs in order to achieve future emission targets and longer-term benefits from GHG reduction. Cost-effectiveness of GHG strategies is likely to require technological mitigation interventions and/or demand-constraining interventions with important health co-benefits and other efficiency-enhancing policies that promote internalization of externalities. Health co-benefits can play a crucial role in bringing down net costs, but our results also suggest the need for adopting holistic assessment methodologies which give proper consideration to welfare-improving health co-benefits with potentially negative economic repercussions (such as increased longevity).  相似文献   

The fall and recovery of the Tagish Lake meteorite     

Alan R. Hildebrand  Phil J. A. McCausland  Peter G. Brown  Fred J. Longstaffe  Sam D. J. Russell  Edward Tagliaferri  John F. Wacker  Michael J. Mazur 《Meteoritics & planetary science》2006,41(3):407-431

Abstract— The Tagish Lake C2 (ungrouped) carbonaceous chondrite fall of January 18, 2000, delivered ?10 kg of one of the most primitive and physically weak meteorites yet studied. In this paper, we report the detailed circumstances of the fall and the recovery of all documented Tagish Lake fragments from a strewnfield at least 16 km long and 3 to 4 km wide. Nearly 1 kg of “pristine” meteorites were collected one week after the fall before new snow covered the strewnfield; the majority of the recovered mass was collected during the spring melt. Ground eyewitnesses and a variety of instrument‐recorded observations of the Tagish Lake fireball provide a refined estimate of the fireball trajectory. From its calculated orbit and its similarity to the remotely sensed properties of the D‐ and P‐class asteroids, the Tagish Lake carbonaceous chondrite apparently represents these outer belt asteroids. The cosmogenic nuclide results and modeled production indicate a prefall radius of 2.1–2.4 m (corresponding to 60–90 tons) consistent with the observed fireball energy release. The bulk oxygen‐isotope compositions plot just below the terrestrial fractionation line (TFL), following a trend similar to the CM meteorite mixing line. The bulk density of the Tagish Lake material (1.64 ± 0.02 g/cm³) is the same, within uncertainty, as the total bulk densities of several C‐class and especially D‐ and P‐class asteroids. The high microporosity of Tagish Lake samples (?40%) provides an obvious candidate material for the composition of low bulk density primitive asteroids.  相似文献   

EVOLUTION OF RURAL ROADS IN THE NIGERIA COCOA BELT     

Oluwole Aloba  BSc.  M.Phil. 《Singapore journal of tropical geography》1983,4(1):1-10

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Process Considerations for Trolling Borehole Flow Logs     

Phil L. Oberlander  Charles E. Russell 《Ground Water Monitoring & Remediation》2006,26(3):60-67

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Constraints on active galactic nucleus accretion disc viscosity derived from continuum variability     

Rhaana L. C. Starling  Aneta Siemiginowska  Phil Uttley  Roberto Soria 《Monthly notices of the Royal Astronomical Society》2004,347(1):67-73

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Spectropolarimetry of Atomic and Molecular Lines near 4135 nm     

Matthew James Penn  Han Uitenbroek  Alan Clark  Roy Coulter  Phil Goode  Wenda Cao 《Solar physics》2016,291(8):2243-2252

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