Isograds in internally buffered systems without solid solutions: principles and examples     

Judy Baker  Tim Holland  Roger Powell 《Contributions to Mineralogy and Petrology》1991,106(2):170-182

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Respondents' evaluations of a CV survey: a case study based on an economic valuation of the Wildlife Enhancement Scheme, Pevensey Levels in East Sussex     

Jacquelin Burgess  Judy Clark  Carolyn M Harrison 《Area》1998,30(1):19-27

Summary Environmental economists have developed a methodology for eliciting individual preferences by asking respondents to a contingent valuation survey how much they would be willing to pay for specified environmental 'goods'. Contingent valuation generates considerable debate, not least because it is unclear how people arrive at a monetary value or whether the elicited monetary value bears any relation to how individuals actually value the environmental 'good'. In this paper, we present preliminary results from a qualitative study of how respondents construct their responses to a CV survey, to suggest that the methodology does not measure what it purports to measure.  相似文献   

The plinian eruptions of 1912 at Novarupta,Katmai National Park,Alaska   总被引：1，自引：0，他引：1  

Judy Fierstein  Wes Hildreth 《Bulletin of Volcanology》1992,54(8):646-684

The three-day eruption at Novarupta in 1912 consisted of three discrete episodes. Episode I began with plinian dispersal of rhyolitic fallout (Layer A) and contemporaneous emplacement of rhyolitic ignimbrites and associated proximal veneers. The plinian column was sustained throughout most of the interval of ash flow generation, in spite of progressive increases in the proportions of dacitic and andesitic ejecta at the expense of rhyolite. Accordingly, plinian Layer B, which fell in unbroken continuity with purely rhyolitic Layer A, is zoned from >99% to 15% rhyolite and accumulated synchronously with emplacement of the correspondingly zoned ash flow sequence in Mageik Creek and the Valley of Ten Thousand Smokes (VTTS). Only the andesiterichest flow units that cap the flow sequence lack a widespread fallout equivalent, indicating that ignimbrite emplacement barely outlasted the plinian phase. On near-vent ridges, the passing ash flows left proximal ignimbrite veneers that share the compositional zonation of their valley-filling equivalents but exhibit evidence for turbulent deposition and recurrent scour. Episode II began after a break of a few hours and was dominated by plinian dispersal of dacitic Layers C and D, punctuated by minor proximal intraplinian flows and surges. After another break, dacitic Layers F and G resulted from a third plinian episode (III); intercalated with these proximally are thin intraplinian ignimbrites and several andesite-rich fall/flow layers. Both CD and FG were ejected from an inner vent <400 m wide (nested within that of Episode I), into which the rhyolitic lava dome (Novarupta) was still later extruded. Two finer-grained ash layers settled from composite regional dust clouds: Layer E, which accumulated during the D-F hiatus, includes a contribution from small contemporaneous ash flows; and Layer H settled after the main eruption was over. Both are distinct layers in and near the VTTS, but distally they merge with CD and FG, respectively; they are largely dacitic but include rhyolitic shards that erupted during Episode I and were kept aloft by atmospheric turbulence. Published models yield column heights of 23–26 km for A, 22–25 km for CD, and 17–23 km for FG; and peak mass eruption rates of 0.7–1x10⁸, 0.6–2x10⁸, and 0.2–0.4x10⁸ kg s^-1, respectively. Fallout volumes, adjusted to reflect calculated redistribution of rhyolitic glass shards, are 8.8 km³, 4.8 km³, and 3.4 km³ for Episodes I, II, and III. Microprobe analyses of glass show that as much as 0.4 km³ of rhyolitic glass shards from eruptive Episode I fell with CDE and 1.1 km³ with FGH. Most of the rhyolitic ash in the dacitic fallout layers fell far downwind (SE of the vent); near the rhyolite-dominated ignimbrite, however, nearly all of Layers E and H are dacitic, showing that the downwind rhyolitic ash is of co-plinian rather than co-ignimbrite origin.  相似文献   

NONCONTIGUOUS AREA CARTOGRAMS     

Judy M. Olson 《The Professional geographer》1976,28(4):371-380

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The magnetic effects of brecciation and shock in meteorites: III. The achondrites     

Aviva Brecher  Miriam Fuhrman  Judy Stein 《Earth, Moon, and Planets》1979,20(3):265-279

We present results of a magnetic survey of achondritic meteorites, representing the aubrites (A), diogenites (D), Irowardites (H), and eucrites (E) groups and relate their magnetic behavior to respective class characteristics and models of origin.Magnetic susceptibility (x) values cluster well within each group and decrease systematically between groups (from 2 to 0.1×10^–3GOe^–1 cm^–3), with the average metal contents, (from 1 to <0.1 wt%) in the above order. The natural remanent magnetization (NRM) values range broadly within each group, but group averages decrease roughly as above. However, the considerable within-sample and intra-group variability in NRM level and its demagnetization characteristics attest to inhomogeneous and localized brecciation effects. Although petrological-chemical studies resolve a primary component of magmatic differentiation on the planetoid of origin, no clear magnetic record of such event has been preserved. The magnetization of achondrites is mainly the product of their complex, multi-stage impact brecciation and metamorphism history, in accord with other lines of evidence.The magnetic behavior of achondrites is remarkably similar to that characteristic of lunar breccias and impact-melt rocks and reinforces their analogous mode of genesis, as brought out by chemical and petrographic analyses.  相似文献   

Comment: Holocene palaeoceanographic changes in Barrow Strait,Canadian Arctic: foraminiferal evidence. T. R. Gregory,C. W. Smart,M. B. Hart,G. MassÉ, L. L. Vare and S. T. Belt (2010). Journal of Quaternary Science 25: 903–910     

Mark F.A. Furze  Anna J. Pieńkowski  John H. England 《第四纪科学杂志》2010,25(7):1189-1192

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Facies and stratigraphical analyses of glacial and interglacial sediments at Morgan Bluffs,Banks Island,Canadian Arctic Archipelago     

Thomas R. Lakeman  John H. England 《Boreas: An International Journal of Quaternary Research》2014,43(4):895-913

Stratigraphical exposures of both glacial and non‐glacial sediments at Morgan Bluffs, a >6‐km long exposure on the east coast of Banks Island, comprise a discontinuous archive of Quaternary environmental change. A detailed facies analysis of the sediments and a new stratigraphical framework is incompatible with the many climatostratigraphical units proposed previously. Instead, three distinct intervals of sedimentation are recognized. The first records the progradation of a delta, followed by fluvial aggradation of a braided river valley perhaps ～1 Ma. The second documents glacigenic sedimentation, including fluctuations of a tidewater glacier margin, in a marine basin more than 0.78 Ma. The third records till deposition by the NW Laurentide Ice Sheet during the Late Wisconsinan, followed by the progradation of a deglacial, ice‐contact delta into an ice‐dammed lake ～12.8 cal. ka BP. The revised stratigraphical framework adds important new terrestrial observations to a sparse and fragmentary data set of Quaternary environmental change in the Canadian Arctic. This study challenges former references and correlations to the previously proposed climatostratigraphical framework and nomenclature.  相似文献   

The deglacial to postglacial marine environments of SE Barrow Strait,Canadian Arctic Archipelago     

Anna J. Pieńkowski  John H. England  Mark F.A. Furze  Fabienne Marret  Frédérique Eynaud  Gustav Vilks  Brian Maclean  Steve Blasco  James D. Scourse 《Boreas: An International Journal of Quaternary Research》2012,41(2):141-179

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The exaggerated radiocarbon age of deposit‐feeding molluscs in calcareous environments     

John England  Arthur S. Dyke  Roy D. Coulthard  Roger Mcneely  Alec Aitken 《Boreas: An International Journal of Quaternary Research》2013,42(2):362-373

Throughout northern Canada, live‐collected, pre‐bomb, deposit‐feeding marine molluscs from calcareous sediments yield greater apparent radiocarbon ages than do suspension feeders. We explore the size of this effect in a set of 57 paired datings of deposit feeders, mainly Portlandia arctica, and suspension feeders, mainly Hiatella arctica and Mya truncata, collected from both calcareous and non‐calcareous Holocene sediments. Deposit feeders from calcareous sediments are older than their suspension‐feeding counterparts by as much as 2240±130 ¹⁴C years. This is attributed to the uptake of ‘old’ bicarbonate derived from calcareous bedrock. The age discrepancy between suspension and deposit feeders in calcareous terrain is non‐systematic in space and time, thereby invalidating the application of a correction. In contrast, the age comparisons are concordant at sites located on the Precambrian Shield. In terrestrial environments underlain by carbonate, previous acceptance of dates on deposit feeders led to erroneous interpretations of deglaciation and relative sea‐level history, in both the North American and the Eurasian Arctic. This has prompted several researchers to exclude deposit feeders from their late Quaternary reconstructions. The same chronological problem of deposit‐feeding molluscs now needs to be more widely acknowledged by the marine community.  相似文献   

Integrating the effects of flood experience on risk perception with responses to changing climate risk     

Judy Lawrence  Dorothee Quade  Julia Becker 《Natural Hazards》2014,74(3):1773-1794

Flood management decision-makers face significant challenges as the climate changes. The perceptions of those affected by floods are critical to the successful implementation of adaptation responses; risk perceptions are affected by how information is communicated and, in turn, perceptions influence expectations on flood risk managers to respond. The links between flood experience, risk perception, and responses by individual households were examined in the Hutt Valley, New Zealand, through a household survey, a workshop and interviews with local government practitioners. Two propositions were tested: (1) that flood experience can influence flood risk perceptions; and (2) that flood experience can stimulate increased risk reduction and adaptation actions where changing climate risk is likely. Perceptions of responsibility for flood management were also examined. The study found that previous flood experience contributes to heightened perception of risk, increased preparedness of households, greater willingness to make household-level changes, greater communication with councils, and more advocacy for spatial planning to complement existing structural protection. Flood-affected households had a stronger preference for central government and communities having flood risk responsibilities, in addition to local government. Those who lacked experience were more likely to be normalised to their prior benign experiences and thus optimistic about flood consequences. These results suggest that harnessing positive aspects of experience and communication of changing risk through engagement strategies could help shift the focus from citizens’ expectation that governments will always provide protection, to a citizen–local government–central government dialogue about the changing character of flood risk and its implications, and build a ‘risk conscious’ society in which ‘sharing and bearing’ is considered desirable.  相似文献