Erratum to: “A robust surface matching technique for coastal geohazard assessment and management” [ISPRS J. Photogramm. Remote Sens. 63 (2008) 529–542]     

Pauline Miller  Jon Mills  Stuart Edwards  Paul Bryan  Stuart Marsh  Harvey Mitchell  Peter Hobbs 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(2):243-245

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The age, metallicity and α-element abundance of Galactic globular clusters from single stellar population models     

Jon T. Mendel  Robert N. Proctor  Duncan A. Forbes 《Monthly notices of the Royal Astronomical Society》2007,379(4):1618-1636

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Environmental correlates of large-scale spatial variation in the δ13C of marine animals     

Carolyn Barnes  Simon Jennings  Jon. T. Barry 《Estuarine, Coastal and Shelf Science》2009,81(3):368-374

Carbon stable isotopes can be used to trace the sources of energy supporting food chains and to estimate the contribution of different sources to a consumer's diet. However, the δ¹³C signature of a consumer is not sufficient to infer source without an appropriate isotopic baseline, because there is no way to determine if differences in consumer δ¹³C reflect source changes or baseline variation. Describing isotopic baselines is a considerable challenge when applying stable isotope techniques at large spatial scales and/or to interconnected food chains in open marine environments. One approach is to use filter-feeding consumers to integrate the high frequency and small-scale variation in the isotopic signature of phytoplankton and provide a surrogate baseline, but it can be difficult to sample a single consumer species at large spatial scales owing to rarity and/or discontinuous distribution. Here, we use the isotopic signature of a widely distributed filter-feeder (the queen scallop Aequipecten opercularis) in the north-eastern Atlantic to develop a model linking base δ¹³C to environmental variables. Remarkably, a single variable model based on bottom temperature has good predictive power and predicts scallop δ¹³C with mean error of only 0.6‰ (3%). When the model was used to predict an isotopic baseline in parts of the overall study region where scallop were not consistently sampled, the model accounted for 76% and 79% of the large-scale spatial variability (10¹–10⁴ km) of the δ¹³C of two fish species (dab Limanda limanda and whiting Merlangus merlangius) and 44% of the δ¹³C variability in a mixed fish community. The results show that source studies would be significantly biased if a single baseline were applied to food webs at larger scales. Further, when baseline δ¹³C cannot be directly measured, a calculated baseline value can eliminate a large proportion of the unexplained variation in δ¹³C at higher trophic levels.  相似文献   

The Monitor project: JW 380 – a 0.26-, 0.15-M_⊙, pre-main-sequence eclipsing binary in the Orion nebula cluster     

Jonathan Irwin  Suzanne Aigrain  Simon Hodgkin  Keivan G. Stassun  Leslie Hebb  Mike Irwin  Estelle Moraux  Jerome Bouvier  Aude Alapini  Richard Alexander  D. M. Bramich  Jon Holtzman  Eduardo L. Martín  Mark J. McCaughrean  Frédéric Pont  P. E. Verrier  María Rosa Zapatero Osorio 《Monthly notices of the Royal Astronomical Society》2007,380(2):541-550

We present a general recipe for constructing N -body realizations of galaxies comprising near spherical and disc components. First, an exact spherical distribution function for the spheroids (halo and bulge) is determined, such that it is in equilibrium with the gravitational monopole of the disc components. Second, an N -body realization of this model is adapted to the full disc potential by growing the latter adiabatically from its monopole. Finally, the disc is sampled with particles drawn from an appropriate distribution function, avoiding local-Maxwellian approximations. We performed test simulations and find that the halo and bulge radial density profile very closely match their target model, while they become slightly oblate due to the added disc gravity. Our findings suggest that vertical thickening of the initially thin disc is caused predominantly by spiral and bar instabilities, which also result in a radial re-distribution of matter, rather than scattering off interloping massive halo particles.  相似文献   

The 2dF-SDSS LRG and QSO (2SLAQ) Luminous Red Galaxy Survey     

Russell Cannon  Michael Drinkwater  Alastair Edge  Daniel Eisenstein  Robert Nichol  Phillip Outram  Kevin Pimbblet  Roberto De Propris  Isaac Roseboom  David Wake  Paul Allen  Joss Bland-Hawthorn  Terry Bridges  Daniel Carson  Kuenley Chiu  Matthew Colless  Warrick Couch  Scott Croom  Simon Driver  Stephen Fine  Paul Hewett  Jon Loveday  Nicholas Ross  Elaine M. Sadler  Tom Shanks  Robert Sharp  J. Allyn Smith  Chris Stoughton  Peter Weilbacher  Robert J. Brunner  Avery Meiksin  Donald P. Schneider 《Monthly notices of the Royal Astronomical Society》2006,372(1):425-442

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The Wide Field Spectrograph (WiFeS): performance and data reduction     

Michael Dopita  Jonghwan Rhee  Catherine Farage  Peter McGregor  Gabe Bloxham  Anthony Green  Bill Roberts  Jon Neilson  Greg Wilson  Peter Young  Peter Firth  Gianni Busarello  Paola Merluzzi 《Astrophysics and Space Science》2010,327(2):245-257

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Arecibo radar observations of Phobos and Deimos     

Michael W. Busch  Steven J. Ostro  Jon D. Giorgini  Ellen S. Howell  Alice A. Hine  Irwin I. Shapiro 《Icarus》2007,186(2):581-584

In November 2005, we observed the moons of Mars using the Arecibo 2380-MHz (13-cm) radar, obtaining a result for the OC radar albedo of Phobos (0.056±0.014) consistent with its previously reported radar albedo and implying an upper bound on its near-surface bulk density of . We detected Deimos by radar for the first time, finding its OC radar albedo to be 0.021±0.006, implying an upper bound on its near-surface density of , consistent with a high-porosity regolith. We briefly discuss reasons for these low radar albedos, Deimos' being possibly the lowest of any Solar System body yet observed by radar.  相似文献   

Geochemical and Sr–O isotopic constraints on magmatic differentiation at Gede Volcanic Complex, West Java, Indonesia     

Heather Katherine Handley  Colin G. Macpherson  Jon P. Davidson 《Contributions to Mineralogy and Petrology》2010,159(6):885-908

The Gede Volcanic Complex (GVC) of the Sunda island arc (West Java, Indonesia) consists of multiple volcanic centres and eruptive groups with complex magmatic histories. We present new petrological, mineralogical, whole-rock major and trace element and Sr–O isotopic data to provide constraints on the relative importance of fractional crystallisation and magma mixing in petrogenesis, as well as on the role and nature of the arc crust. Banded juvenile scoria from Young and Old Gede provide unequivocal evidence for the (late-stage) interaction of distinct magmas at Gede volcano. However, the relatively small-degree compositional zoning observed in plagioclase phenocrysts of all eruptive groups (up to ~20 mol% An) may be attributed to physical changes in magma properties (e.g. P, T, and PH₂O) rather than changes in melt composition. Major element and trace element variations within each eruptive series are inconsistent with magmatic evolution through simple mixing processes. Instead, mixing of variably fractionated magma batches is suggested to account for the significant scatter in some element variation diagrams. No correlation is observed between textural complexity and/or mineral disequilibrium and whole-rock geochemistry. REE data and geochemical modelling indicate that fractional crystallisation involving amphibole in the mid- to lower crust, and fractionation of plagioclase, clinopyroxene, Fe–Ti oxide ± olivine ± orthopyroxene provide strong control on the geochemical evolution of GVC rocks. Two-pyroxene geothermobarometry provides pre-eruption crystallisation temperatures of 891–1,046°C and pressures of 3.4–6.5 kbar, equivalent to ~13–24 km depth beneath the volcanoes (mid- to lower crust). Low, mantle-like clinopyroxene δ¹⁸O values of GVC lavas and poor correlation of Sr isotope ratios with indices of differentiation precludes significant assimilation of isotopically distinct crust during magmatic differentiation. Therefore, we suggest that the geochemical character of the moderately thick West Javan arc crust is relatively immature compared to typical continental crust. Trace element ratios and strontium isotopes show that the magmatic source composition of the older geographical units, Gegerbentang and Older Quaternary, is distinct from the other GVC groups.  相似文献   

Long-Term Observations of Isotope Ratio Accuracy and Reproducibility Using Quadrupole ICP-MS     

Thomas Ulrich  Balz S. Kamber  Jon D. Woodhead  Lizzy A. Spencer 《Geostandards and Geoanalytical Research》2010,34(2):161-174

High precision isotope ratio and trace element determination can be achieved with modern quadrupole ICP-MS provided that short and long-term instrument performance is accurately monitored. Here we present results for the isotope ratios ⁶Li/⁷Li, ¹⁴⁷Sm/¹⁴⁹Sm, ¹⁶⁰Dy/¹⁶¹Dy, ²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb, ²⁰⁶Pb/²⁰⁴Pb and ²³⁵U/²³⁸U with which we determined long-term isotope ratio stability of relevance to both trace element and isotope determination. With respect to trace element determination, we first present long-term observations regarding oxide formation rates of Ba and Nd on light REE and heavy REE, as well as Zr on Ag. These showed good correlations and could be used to correct effectively the interference. The efficacy of this correction was demonstrated with analyses of the rock reference material BHVO-2 at both low and high oxide formation rates. Next, we studied the long-term reproducibility of a Dy isotope ratio that was measured to correct for the isobaric interference on Gd. It was found that, regardless of tuning condition, the ratio reproduced very well (0.58% RSD, 1s) and that the estimate of the Gd concentration did not suffer from the large correction (> 10%) caused by the Dy isobar. Long-term reproducibilities of Li, Sm and U isotope ratios, required for accurate mass bias correction when isotopically enriched internal standards of these elements are employed, were measured in the rock reference materials AGV-2 and JA-3 over a time period of up to 3 years. As expected, the Li isotope ratio showed the largest variability (RSD = 7%), but the other two ratios had relative external reproducibilities of only 1.01% (1s, U) and 0.67% (Sm). The mass bias-induced scatter in measurements for Sm and U was so small that the internal standard correction was effective, even for samples with high concentrations of these elements. With regard to Pb-isotope ratio determination, we also present long-term reproducibility for NIST SRM 982, run as an unknown and two accuracy tests for Pb separated from granitoids and from meteorites. It is demonstrated that the obtained ratios, including those involving ²⁰⁴Pb, are accurate relative to MC-ICP-MS determinations and of comparable precision to conventional TIMS analysis. The excellent agreement between all data sets shows the potential of modern quadrupole ICP-MS instrumentation for Pb-isotope determination, particularly for samples with very low Pb content.  相似文献   

Proximity to ice fields and lake depth as modulators of paleoclimate records: a regional study from southwest Yukon,Canada     

Guangjie Chen  Daniel T. Selbie  Katherine Griffiths  Jon N. Sweetman  Morgan Botrel  Zofia E. Taranu  Sébastien Knops  Jennifer Bondy  Neal Michelutti  John P. Smol  Irene Gregory-Eaves 《Journal of Paleolimnology》2014,52(3):185-200

Pronounced climate warming during the past century has been well documented in high-latitude regions. Nonetheless, considerable heterogeneity exists in northern climate trends. We examined the roles of cryospheric landscape and lake depth in modulating the rate and magnitude of local climate responses through a paleolimnological study of lakes from southwest Yukon, Canada. By sampling lakes at varying distances from the Wrangell-St. Elias ice fields, we hypothesized that, for lakes of similar maximum depth, sites closest to the ice fields would be relatively complacent in terms of their chironomid and diatom assemblage changes over the past ~200 years. This hypothesis is based on the moderating effect of the glaciers on local climate, which would be most pronounced in the lakes nearest to the ice fields. However, given the known ecological differences between deep and shallow lakes, we further predicted that, for a given distance from the ice fields, a sediment record from a shallower lake would show the greatest change in stratigraphic subfossil assemblages. Because of the complicated shape of the ice fields, we applied the longitude for each site (which decreases from west to east) to approximate the proximity of our study lakes to the ice fields. Consistent with our predictions, we observed a space-transgressive pattern in the chironomid assemblage turnover that was associated with their proximity to the ice fields (r = ?0.75, P = 0.034, n = 8) across lakes of similar depth (mean maximum depth ± 1, SE = 18.1 ± 2.6 m). Considering a broader network of lakes that represented a greater range in maximum depth (4.9–29 m), we found that differences in subfossil chironomid assemblages between the modern and ca. AD 1800 sediment layers were strongly related to lake depth (r = ?0.77, P < 0.001, n = 15), but failed to detect a significant relationship with latitude or longitude (i.e. our proxy for proximity to the ice fields). Similarly, our comparative high-resolution analyses of two lakes with distinct lake morphometries, but similar proximities to the ice fields, demonstrated the predicted contrasting pattern: we observed pronounced post-1880 changes in the biotic assemblages in the shallow lake and a muted and delayed response (i.e. ~1970s) in the deeper lake. Our findings confirm that cryospheric landscape features can strongly modulate regional climate. Furthermore, our work shows that investigators need to be conscious of how climate change affects the structure and functioning of lakes of different typologies, which influences the way in which paleoclimate signals are recorded and interpreted.  相似文献