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Ricardo Génova-Santos José Alberto Rubiño-Martín Rafael Rebolo † Kieran Cleary ‡ Rod D. Davies Richard J. Davis Clive Dickinson § Nelson Falcón ‡‡ Keith Grainge Carlos M. Gutiérrez Michael P. Hobson Michael E. Jones ¶ Rüdiger Kneissl &#; Katy Lancaster Carmen P. Padilla-Torres Richard D. E. Saunders Paul F. Scott Angela C. Taylor ¶ Robert A. Watson †† 《Monthly notices of the Royal Astronomical Society》2005,363(1):79-92
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Fiona?Elizabeth?Mothersole Katy?EvansEmail authorView author&#;s OrcID profile B.?Ronald?Frost 《Contributions to Mineralogy and Petrology》2017,172(8):69
Subduction of serpentinised mantle transfers oxidised and hydrated mantle lithosphere into the Earth, with consequences for the oxidation state of sub-arc mantle and the genesis of arc-related ore deposits. The role of subducted serpentinised mantle lithosphere in earth system processes is uncertain because subduction fluxes are poorly constrained. Most subducted serpentinised mantle is serpentinised on the ocean floor settings. Yet this material is poorly represented in the literature because it is difficult to access. Large volumes of accessible serpentinite are available in ophiolite complexes, and most interpretations of subduction fluxes associated with ultramafic rocks are based on ophiolite studies. Seafloor and ophiolite serpentinisation can occur under different conditions, so it is necessary to assess if ophiolite serpentinites are a good proxy for seafloor serpentinites. Serpentinites sampled during ODP cruise 209 were compared with serpentinites from New Caledonia. The ODP209 serpentinites were serpentinised by modified seawater in a shallow hydrothermal seafloor setting. The New Caledonia serpentinites were serpentinised in a mantle wedge setting by slab-derived fluids, with possible contributions from oceanic serpentinisation and post-obduction serpentinisation. Petrological, whole rock and mineralogical analyses were combined to compare the two sample sets. Petrologically, the evolution of serpentinisation was close to identical in the two environments. However, more oxidised iron, Cl, S and C is present in serpentine from the ODP209 serpentinites relative to the New Caledonia serpentinites. Given these observations, the use of serpentinites from different geodynamic settings as a proxy for abyssal serpentinites from spreading settings must be undertaken with caution. 相似文献
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Many individual-level behaviors are associated with greenhouse gas (GHG) emissions. Reliable and valid assessment instruments are needed to (1) identify behaviors and populations to target with emissions-reduction programs and policies, (2) evaluate the effectiveness of such programs, (3) link self-reported and objective measures of GHG emissions to establish the impact of specific behaviors, and (4) estimate frequencies of behaviors and their changes over time to aid policy makers in understanding energy consumption trends. The self-administered Stanford Climate Change Behavior Survey (SCCBS) is shown to be a reliable and valid instrument that can be used for these purposes in college students, and we anticipate that it will also be useful for assessing these behaviors in other adolescent or adult populations in developed countries. Questions included behaviors likely to be within the control of most individuals and did not include behaviors specific to home owners (e.g. appliance purchases). Ten indices were identified: Energy Use, No-, Low-, and High-GHG Transportation, Waste, Food Packaging, High- and Low-GHG Food, Food Purchasing, and GHG Credits use. A Total GHG Behavior score was calculated. Test–retest reliabilities of individual items ranged from .64 to .91. Internal consistency reliabilities for each of the indices ranged from .51 to .89. Most indices were statistically significantly correlated with one another. Correlational validity of the SCCBS was demonstrated with statistically significant associations between behavior scores and perceived importance of environmental sustainability and membership in an environmental organization. The use of the SCCBS to identify potential target sub-populations and behaviors was demonstrated. 相似文献
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Nick E. Timms Peter D. Kinny Steven M. Reddy Katy Evans Chris Clark Dave Healy 《Chemical Geology》2011,280(1-2):33-46
A zircon grain in an orthopyroxene–garnet–phlogopite–zircon–rutile-bearing xenolith from Udachnaya, Siberia, preserves a pattern of crystallographic misorientation and subgrain microstructure associated with crystal–plastic deformation. The zircon grain records significant variations in titanium (Ti) from 2.6 to 30 ppm that corresponds to a difference in calculated Ti-in-zircon temperatures of over several hundred degrees Celsius. The highest Ti concentration is measured at subgrain centres (30 ppm), and Ti is variably depleted at low-angle boundaries (down to 2.6 ppm). Variations in cathodoluminescence coincide with the deformation microstructure and indicate localised, differential enrichment of rare earth elements (REE) at low-angle boundaries. Variable enrichment of U and Th and systematic increase of Th/U from 1.61 to 3.52 occurs at low-angle boundaries. Individual SHRIMP-derived U–Pb ages from more deformed zones (mean age of 1799 ± 40, n = 22) are systematically younger than subgrain cores (mean age of 1851 ± 65 Ma, n = 7), and indicate that open system behaviour of Ti–Th–U occurred shortly after zircon growth, prior to the accumulation of significant radiogenic Pb. Modelling of trace-element diffusion distances for geologically reasonable thermal histories indicates that the observed variations are ~ 5 orders of magnitude greater than can be accounted for by volume diffusion. The data are best explained by enhanced diffusion of U, Th and Ti along deformation-related fast-diffusion pathways, such as dislocations and low-angle (< 5°) boundaries. These results indicate chemical exchange between zircon and the surrounding matrix and show that Ti-in-zircon thermometry and U–Pb geochronology from deformed zircon may not yield information relating to the conditions and timing of primary crystallisation. 相似文献
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Katy A. Boon Peter Rostron Michael H. Ramsey 《Geostandards and Geoanalytical Research》2011,35(3):353-367
In the assessment of potentially contaminated land, the number of samples and the uncertainty of the measurements (including that from sampling) are both important factors in the planning and implementation of an investigation. Both parameters also effect the interpretation of the measurements produced, and the process of making decisions based upon those measurements. However, despite their importance, previously there has been no method for assessing if an investigation is fit‐for‐purpose with respect to both of these parameters. The Whole Site Optimised Contaminated Land Investigation (WSOCLI) method has been developed to address this issue, and to allow the optimisation of an investigation with respect to both the number of samples and the measurement uncertainty, using an economic loss function. This function was developed to calculate an ‘expectation of (financial) loss’, incorporating costs of the investigation itself, subsequent land remediation, and potential consequential costs. To allow the evaluation of the WSOCLI method a computer program ‘OCLISIM’ has been developed to produce sample data from simulated contaminated land investigations. One advantage of such an approach is that as the ‘true’ contaminant concentrations are created by the program, these values are known, which is not the case in a real contaminated land investigation. This enables direct comparisons between functions of the ‘true’ concentrations and functions of the simulated measurements. A second advantage of simulation for this purpose is that the WSOCLI method can be tested on many different patterns and intensities of contamination. The WSOCLI method performed particularly well at high sampling densities producing expectations of financial loss that approximated to the true costs, which were also calculated by the program. WSOCLI was shown to produce notable trends in the relationship between the overall cost (i.e., expectation of loss) and both the number of samples and the measurement uncertainty, which are: (a) low measurement uncertainty was optimal when the decision threshold was between the mean background and the mean hot spot concentrations. (b) When the hot spot mean concentration is equal to or near the decision threshold, then mid‐range measurement uncertainties were optimal. (c) When the decision threshold exceeds the mean of the hot spot, mid‐range measurement uncertainties were optimal. The trends indicate that the uncertainty may continue to rise if the difference between hot spot mean and the decision threshold increases further. (d) In any of the above scenarios, the optimal measurement uncertainty was lower if there is a large geochemical variance (i.e., heterogeneity) within the hot spot. (e) The optimal number of samples for each scenario was indicated by the WSOCLI method, and was between 50 and 100 for the scenarios considered generally; although there was significant noise in the predictions, which needs to be addressed in future work to allow such conclusions to be clearer. 相似文献
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Katy Bennett 《Area》2009,41(3):244-251
This paper contributes to work on emotional geographies by engaging with Liz Bondi's focus on relationality and the challenge to geographers to explore how their emotion might connect with the feelings of their subjects. Through the lens of a focus group meeting that created confusing feelings, it shows the hurdles that geographers face when they engage with practices developed in a psychotherapeutic setting. The paper is not so much a critique, more a desire to continue the conversation regarding how to approach and adopt psychotherapy's theory of practice in a research context . 相似文献
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Katy Mee Jennie S. Gilbert David W. McGarvie José A. Naranjo Malcolm S. Pringle 《Bulletin of Volcanology》2009,71(8):933-952
Nevados de Chillán Volcanic Complex, central Chile, has been active for at least 640 ka—a period spanning a number of glacial
and interglacial periods. Geologic mapping, radiometric dating and geochemical analysis have identified six new volcanic units
and produced four new 40Ar/39Ar ages for Cerro Blanco, the northern subcomplex of Nevados de Chillán volcano. Compositions range from dacite to basaltic-andesite
and a new geologic map is presented. Examination of lava fracture structures on both newly mapped lavas and those mapped during
previous studies has enabled interpretations of former eruptive environments. Palaeoenvironment reconstructions, combined
with 40Ar/39Ar ages and comparison with the marine oxygen isotope record, show that at least three phases of volcanic activity have occurred
during the evolution of Cerro Blanco: (1) a constructive, pre-caldera collapse period; (2) a period of caldera formation and
collapse; and (3) a constructive period of dome growth forming the modern day volcanic centre. This style of volcanic evolution,
whereby large-scale caldera collapse is followed by growth of a new stratocone is common at Andean volcanoes. 相似文献
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Late Holocene volcanic activity at Ruapehu has been characterizedby the generation of small (<105 m3) to very large (>107 m3) lahars and repeated,small to medium (VEI 1-3) tephra-producing eruptions. The Onetapu Formation groupsall lahar deposits that accumulated during the last 2,000 years on the southeastern Ruapehu ring plain. The andesitic tephras are grouped within the Tufa Trig Formation and are intercalated within the laharic sequence. By correlating these two formations with new radiocarbon ages obtained on interbedded paleosols, we reconstruct a detailed volcanic history of Ruapehu for this period.Clast assemblages identified in the laharic sequences record thelithologies of synchronous tephras and rocks within the source region. These assemblages suggest a strong genetic link between the development of Crater Lake, the variation in eruptivestyles, and the production of lahars.Lahar-triggering mechanisms include: (1) flank collapse ofhydrothermally altered and unstable portions of the cone; (2) phreatic and phreatomagmatic eruptions favoring the generation of snow-rich slurries and hyperconcentrated stream flows; (3) suddenCrater Lake rim collapse, releasing large amounts of water inducing debris flows; and (4) eruptions that generate large volumes of tephra on snow-covered slopes, later remobilized by heavy rain.Two major lahars in the Onetapu sequence had a volume 4 × 107 m3, roughly 1 to 2 orders of magnitude larger than the 1953event leading to the Tangiwai disaster (151 casualties). One of these lahars crossed over a lowinterfluve currently separating the Whangaehu River from a stream feeding the Tongariro River,sometime since peat accumulated between AD 1400 and AD 1660. A repetition of such a large-scaleevent would have devastating consequences on the infrastructure, economy and environment withinthe distal areas of the two catchments. The 1995–1996 eruptions were a timely reminder ofthe hazards posed by the volcano. 相似文献