In situ multiple sulfur isotope analysis by SIMS of pyrite, chalcopyrite, pyrrhotite, and pentlandite to refine magmatic ore genetic models

With growing interest in the application of in situ multiple sulfur isotope analysis to a variety of mineral systems, we report here the development of a suite of sulfur isotope standards for distribution relevant to magmatic, magmatic-hydrothermal, and hydrothermal ore systems. These materials include Sierra pyrite (FeS2), Nifty-b chalcopyrite (CuFeS2), Alexo pyrrhotite (Fe(1 −x)S), and VMSO pentlandite ((Fe,Ni)9S8) that have been chemically characterized by electron microprobe analysis, isotopically characterized for δ33S, δ34S, and δ36S by fluorination gas-source mass spectrometry, and tested for homogeneity at the micro-scale by secondary ion mass spectrometry. Beam-sample interaction as a function of crystallographic orientation is determined to have no effect on δ34S and Δ33S isotopic measurements of pentlandite. These new findings provided the basis for a case study on the genesis of the Long-Victor nickel-sulfide deposit located in the world class Kambalda nickel camp in the southern Kalgoorlie Terrane of Western Australia. Results demonstrate that precise multiple sulfur isotope analyses from magmatic pentlandite, pyrrhotite and chalcopyrite can better constrain genetic models related to ore-forming processes. Data indicate that pentlandite, pyrrhotite and chalcopyrite are in isotopic equilibrium and display similar Δ33S values + 0.2‰.This isotopic equilibrium unequivocally fingerprints the isotopic signature of the magmatic assemblage. The three sulfide phases show slightly variable δ34S values (δ34Schalcopyrite = 2.9 ± 0.3‰, δ34Spentlandite = 3.1 ± 0.2‰, and δ34Spyrrhotite = 3.9 ± 0.5‰), which are indicative of natural fractionation. Careful in situ multiple sulfur isotope analysis of multiple sulfide phases is able to capture the subtle isotopic variability of the magmatic sulfide assemblage, which may help resolve the nature of the ore-forming process. Hence, this SIMS-based approach discriminates the magmatic sulfur isotope signature from that recorded in metamorphic- and alteration-related sulfides, which may not be resolved during bulk rock fluorination analysis. The results indicate that, unlike the giant dunite-hosted komatiite systems that thermo-mechanically assimilated volcanogenic massive sulfides proximal to vents and display negative Δ33S values, the Kambalda ores formed in relatively distal environments assimilating abyssal sulfidic shales

The ammonites of the Middle Jurassic Cranocephalites beds of East Greenland. Appendix: pages 129-145

Appendix: Description of a new Bajocian (Middle Jurassic) ammonite species, Cranocephalites tvaerdalensis sp.nov., from Geographical Society Ø, North-East Greenland. A new Cranocephalites species, C. tvaerdalensis sp. nov., is described. Its type locality is a restricted outcrop of the Pelion Formation in Tværdal on Geographical Society Ø, North-East Greenland. It belongs to the C. carlsbergensis group and has its type horizon in the upper Bajocian (Middle Jurassic) Pompeckji Zone

The ammonites of the Middle Jurassic Cranocephalites beds of East Greenland, Plates 1-20

Thick successions of marine Middle Jurassic deposits rich in ammonites occur in the Jameson Land Basin in central East Greenland. The fauna of the so-called Cranocephalites beds of this basin, comprising the Borealis–Pompeckji Standard Zones, was until now largely represented by a single collection. This was made by T.M. Harris during a 1927 excursion up the valley of Ugleelv to Katedralen, the type area of Cranocephalites pompeckji, which is the oldest named species of this genus. Revisits to this area in 1994 and 1996 by JHC resulted in a large bed-by-bed collection of Cranocephalites. The number of faunal horizons that could be distinguished grew from the nine previously recognised to thirty-four today. The zonal stratigraphy of the Cranocephalites beds encompasses the Borealis, Indistinctus and Pompeckji Standard Zones. The Pompeckji Zone is subdivided into four new subzones, reflecting four successive basic morphologies of Cranocephalites that should be recognisable more widely and are thus useful for subzonal correlations. The detailed zonation that serves as the secondary standard zonation for the Boreal Province in the Middle Jurassic is thus highly improved. The biostratigraphic resolution obtained here is near the achievable limits. It allows a high-resolution study of the evolution of the ammonites which on this timescale appears to be continuous. Three new species are described: Cranocephalites carolae sp. nov., Cranocephalites intermissus sp. nov. and Cranocephalites episcopalis sp. nov. An additional new species, Cranocephalites tvaerdalensis sp. nov., is described in the appendix by P. Alsen based on collections from Tværdal on Geographical Society Ø, North-East Greenland. This species is also recorded in Jameson Land

The ammonites of the Middle Jurassic Cranocephalites beds of East Greenland, pages 01-86

Thick successions of marine Middle Jurassic deposits rich in ammonites occur in the Jameson Land Basin in central East Greenland. The fauna of the so-called Cranocephalites beds of this basin, comprising the Borealis–Pompeckji Standard Zones, was until now largely represented by a single collection. This was made by T.M. Harris during a 1927 excursion up the valley of Ugleelv to Katedralen, the type area of Cranocephalites pompeckji, which is the oldest named species of this genus. Revisits to this area in 1994 and 1996 by JHC resulted in a large bed-by-bed collection of Cranocephalites. The number of faunal horizons that could be distinguished grew from the nine previously recognised to thirty-four today. The zonal stratigraphy of the Cranocephalites beds encompasses the Borealis, Indistinctus and Pompeckji Standard Zones. The Pompeckji Zone is subdivided into four new subzones, reflecting four successive basic morphologies of Cranocephalites that should be recognisable more widely and are thus useful for subzonal correlations. The detailed zonation that serves as the secondary standard zonation for the Boreal Province in the Middle Jurassic is thus highly improved. The biostratigraphic resolution obtained here is near the achievable limits. It allows a high-resolution study of the evolution of the ammonites which on this timescale appears to be continuous. Three new species are described: Cranocephalites carolae sp. nov., Cranocephalites intermissus sp. nov. and Cranocephalites episcopalis sp. nov. An additional new species, Cranocephalites tvaerdalensis sp. nov., is described in the appendix by P. Alsen based on collections from Tværdal on Geographical Society Ø, North-East Greenland. This species is also recorded in Jameson Land

Donald Judd, The Multicolored Works

Aux approches traditionnelles de la couleur en Histoire de l’art, attentives à l’évolution des théories optiques de l’Antiquité à Isaac Newton, de Goethe à Paul Signac se sont ajoutés récemment des travaux anthropologiques, intéressés par la couleur comme terrain d’une pratique sociale et professionnelle, ainsi l’ouvrage The Color Revolution de Regina Lee Blaszczyk (Cambridge : MIT, 2012). On attend avec impatience la publication de la thèse d’Arnaud Dubois : La Vie chromatique des objets : a..

The experience of visible haematuria among schoolchildren in Umba, Mlola and Mlalo divisions of Lushoto district, Tanga

Objective: To determine the prevalence of S. haematobiuminfection among schoolchildren in the three lowland divisions ofLushoto district. DESIGN: A cross sectional study.Setting: A rapid assessment of the presence of S. haematobiuminfection was conducted using a questionnaire survey amongschoolchildren in 20 primary schools in the three divisions.Subject: Nine thousand and thirty three hundred schoolchildrenaged between 6 and 15 years were examined for S. haematobiuminfection using a questionnaire which asked about past (1 month)and present experience of blood in urine.Results: The prevalence of reported blood in urine was calculated foreach division and Umba division recorded a significantly higherprevalence of 21.6% compared to Mlola and Mlalo divisions whichhad prevalence of 5.9 and 2.0%, respectively. Conclusion: Urinaryschistosomiasis is prevalent in Lushoto district particularly in Umbadivision.Keywords: Schistosoma haematobium, haematuria, questionnaire, prevalence, schoolchildren, Lushot

Evaluation of antimicrobial activities of commonly available toothpastes on oral microbes

Objective: To determine the prevalence of S. haematobiuminfection among schoolchildren in the three lowland divisions ofLushoto district. DESIGN: A cross sectional study.Setting: A rapid assessment of the presence of S. haematobiuminfection was conducted using a questionnaire survey amongschoolchildren in 20 primary schools in the three divisions.Subject: Nine thousand and thirty three hundred schoolchildrenaged between 6 and 15 years were examined for S. haematobiuminfection using a questionnaire which asked about past (1 month)and present experience of blood in urine.Results: The prevalence of reported blood in urine was calculated foreach division and Umba division recorded a significantly higherprevalence of 21.6% compared to Mlola and Mlalo divisions whichhad prevalence of 5.9 and 2.0%, respectively. Conclusion: Urinaryschistosomiasis is prevalent in Lushoto district particularly in Umbadivision.Keywords: Schistosoma haematobium, haematuria, questionnaire, prevalence, schoolchildren, Lushot