Climatic indicators in an ice core from the Yukon [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Stable isotope data obtained from snow and ice cores retrieved from an altitude of 5340m on Mt. Logan (60°30'N; 140°36'W) indicate that "isotopic seasons" are not generally in phase with calendar seasons. The former are phase lagged with respect to the latter by up to several months and appear to be correlated with SST'S and ocean heat transfer curves and/or the position of the Aleutian low rather than with air temperature or the temperature difference between the ocean surface and the core site

Basic principles of stable isotope analysis in humanitarian forensic science.

While the identity of a victim of a localized disaster – such as a train or bus crash – may be established quickly through personal effects, fingerprints, dental records, and a comparison of decedent DNA to family reference specimen DNA, a different scenario presents itself in mass disasters, such as the Asian Tsunami of 2004. In the aftermath of the tsunami, visual appearance was initially used to assign “foreign” or “indigenous” classifications to the remains of thousands of victims. However, this visual identification approach was undermined by the speed with which bodies deteriorated under the hot and humid conditions. Time was spent populating ante-mortem DNA databases for different nationalities, which led to problems when creating a post-mortem DNA database because recovery of viable DNA was compromised due to rapid decomposition. As a consequence, only 1.3% of victims were identified by DNA; in contrast, 61% were identified based on dental examination, although this process took several months and a significant number of deceased from the 2004 Asian Tsunami still remain to be identified

Sulfur Isotopes In Komatiite-hosted Ni-cu Sulfide Deposits From The Morro Do Ferro Greenstone Belt, Southeastern Brazil

In the Morro do Ferro greenstone belt in southeastern Brazil, Ni-Cu massive sulfides hosted by komatiites occur in the vicinity of the town of Fortaleza de Minas. Sulfur-isotope abundances were analyzed in sulfides from the main orebody in order to determine the source of the sulfur. The main sulfide minerals in the ore are pyrrhotite (65%), pentlandite (30%), and chalcopyrite (5%). The δ34S values of the ores fall within a relatively narrow range, but are slightly higher than values for similar occurrences in other greenstone belts. As there does not seem to be evidence of thermal erosion of country rocks and sulfur assimilation, the heavier sulfur possibly is the result of crustal contamination of the ascending komatiite magma and separation of an immiscible sulfide liquid already at this stage.393230238De Almeida, F.F.M., Hasui, Y., Brito Neves, B.B., Fuck, R.A., Brazilian structural provinces (1981) Earth Sci. 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Lett., 92, pp. 144-156Compston, W., Williams, I.S., Campbell, I.H., Gresham, J.J., Zircon xenocrysts from the Kambalda volcanics: Age constraints and direct evidence for older continental crust below the Kambalda Norseman greenstones (1986) Earth Planet. Sci. Lett., 76, pp. 299-311Czamanske, G.K., Kunilov, V.E., Zientek, M.L., Cabri, L.J., Likhachev, A.P., Calk, L.C., Oscarson, R.L., A proton-microprobe study of magmatic sulfide ores from the Nori'sk-Talnakh district, Siberia (1992) Can. Mineral., 30, pp. 249-287Donnelly, T.H., Lambert, I.B., Oehler, D.Z., Hallberg, J.A., Hudson, D.R., Smith, J.W., Bavinton, O.A., Golding, I., A reconnaissance study of stable isotope ratios in Archean rocks from the Yilgarn Block, Western Australia (1977) Jour. Geol. Soc. 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Geol., 87, pp. 437-443Keays, R.R., The role of komatiitic and picritic magmatism and S-saturation in the formation of ore deposits (1995) Lithos, 34, pp. 1-18Lesher, C.M., Lee, R.F., Groves, D.I., Bickle, M.J., Donaldson, M.J., Geochemistry of komatiites from from Kambalda, Western Australia: I. Chalcophile-element depletion, consequence of sulfide liquid separation from komatiitic magma (1981) Econ. Geol., 76, pp. 1714-1728Machado, N., Carneiro, M., U-Pb evidence of late Archean tectono-thermal activity in the southern São Francisco shield, Brazil (1992) Can. Jour. Earth Sci., 29, pp. 2341-2346Machado, N., Schrank, A., Geocronologia U/Pb no maciço de Piumhi: Resultados preliminares (1989) Proc. 5 Simp. Geol. Minas Gerais, pp. 45-49. , Belo Horizonte, MGMarchetto, C.L.M., Platinum group minerals in the O'Toole (Ni-Cu-Co) deposit, Brazil (1990) Econ. 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AmerOhmoto, H., Felder, R., Bacterial activity in the warmer sulfate-bearing Archean oceans (1987) Nature, 328, pp. 244-246Oostindier, J., Vriend, S.P., Huijstmans, J.P.P., Taufen, P.M., Weathered, Ni-sulfide ore-hosting and barren serpentinites in the Fortaleza de Minas greenstone belt, Minas Gerais, Brazil: A rock geochemical study (1990) Chem. Geol., 81, pp. 209-220Ottino, J.M., Muzzio, F.J., Tjahjadi, M., Franijone, J.G., Jana, S.C., Kusch, H.A., Chaos, symmetry, and self-similarity: Exploiting order-disorder in mixing processes (1992) Science, 257, pp. 754-760Paktune, A.D., Hulbert, L.J., Harris, D.C., Partitioning of the platinum-group and other trace elements in sulfides from the Bushveld Complex and Canadian occurrences of nickel-copper sulfides (1990) Can. Mineral., 8, pp. 475-488Roberts, S., Foster, R.P., Nesbitt, R.W., Mineralization associated with early Precambrian basic magmatism (1990) Early Precambrian Basic Magmatism, pp. 157-188. , Hall, R. P., and Hughs, D. J., eds., Glasgow, Blackie and Sons LtdRoig, H.L., Caracterizaçáo da zona de sutura Jacuí-Conceição da Aparecida/MG (1993) Implicações Geotectônicas e Metalogenéticas, 125p. , Unpubl. M.Sc. thesis, University of Campinas, BrazilRye, R.O., Ohmoto, H., Sulfur and carbon isotopes and ore genesis: A review (1974) Econ. Geol., 69, pp. 826-842Sasaki, A., Arikawa, A., Folinsbee, R.E., Kiba reagent method of sulfur extraction applied to isotope work (1979) Bull. Geol. Surv. Japan, 30, pp. 241-245Schmidt, W., (1983) Die Geologie der Araxa Gruppe in Südwest Minas Gerais, Brasilien, Unter Besonderer Berücksichtigung des Grünsteingürtels Von Fortaleza de Minas, 134p. , Unpubl. Ph.D. thesis, Freiburg Univ., GermanySchrank, A., De Abreu, F.R., Roig, H.L., Choudhuri, A., Carvalho, E.D.R., Determinação l dos vectores de transporte tectônico na borda sudoeste do Craton do São Francisco (1990) Proc. 36 Congr. Bras. Geol. 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Regional Geol., 2, Curitiba, Pr, Anais, 1, pp. 328-34

Measurement of selenium isotope abundance variations by ICP-MS

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Superimposed ice observation in summer on ice floes in the Eastern Ross Sea

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Superimposed-ice formation in summer on Ross Sea pack-ice floes

Austral summer sea-ice processes were investigated in January 1999 during a cruise of the R.V. Nathaniel B. Palmer in the central and eastern Ross Sea, Antarctica. The crystal texture, 18O/ 16O ratios, density and salinity of ice cores and of ice blocks 'perched' on slush at the ice surface were studied. The perched ice blocks had a distinctive polygonal granular (PG) crystal texture and very negative isotope signature that were also characteristic of layers at the top of first-year floes and of layers 'buried' below the surface in multi-year floes. The PG ice is superimposed ice that results from melting in the snow cover and refreezing at the slush surface and directly on top of ice floes. If PG ice is buried after the ice surface floods and the resultant slush freezes, then snow ice forms above the PG ice. The contribution of superimposed ice to floe surface mass balance and some implications with respect to weather and climate are discussed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe