Environmental controls on clay mineralogy of an Early Jurassic mudrock (Blue Lias Formation, southern England)

We present a dataset including clay mineralogy, gamma-ray spectrometry, organic matter content and magnetic susceptibility of the Hettangian to lowest Sinemurian successions of Dorset and Somerset, southern UK (Blue Lias Formation, Bristol Channel and Wessex basins). In both areas, the clay assemblages comprise predominantly detrital illite, kaolinite and illite/smectite mixed layers. Clays probably originated from the erosion of the Hercynian massifs, the relative proportions of kaolinite and illite being modulated by arid-humid climatic fluctuations. The organic matter (OM) content (types II to IV) ranges up to 12% in both areas. A clear stratigraphical trend in clay mineral assemblages is apparent in Somerset, whereas in Dorset sharp contrasts between adjacent horizons and a greater dilution by carbonate mask the long-term evolution. Correlations between both areas based on similar vertical trends in clay mineral abundance support the suggestion of a hiatus within the angulata Zone of the Dorset succession. As expected, the kaolinite/illite ratio correlates with the Th/K ratio deduced from gamma-ray spectrometry. However, significant departures from the correlation occur in OM- rich intervals, suggesting that Th may be partly adsorbed on to OM particles. Surprisingly, high magnetic susceptibility correlates with abundant kaolinite, not with Fe-rich clays, indicating either that kaolinite is accompanied by a soil-inherited magnetisable phase (possibly iron oxide) or that illite-rich rocks are more strongly diluted by carbonate than are kaolinite-rich strata

Paecilomyces variotii Fungemia in a Patient with Lymphoma Needing Liver Transplant

International audiencePaecilomyces sp. are emerging pathogens in immunocompromised patients. We report here a case of Paecilomyces variotii fungemia, cured with amphotericin and anidulafungin, illustrating difficulties of early diagnosis and therapeutic choice in such rare fungal infection

Understanding the insulating phase in colossal magnetoresistance manganites : shortening of the Jahn-Teller long-bond across the phase diagram of La1-xCaxMnO3

The detailed evolution of the magnitude of the local Jahn-Teller (JT) distortion in La_{1-x} Ca_x Mn O_3 is obtained across the phase diagram for 0 < x < 0.5 from high quality neutron diffraction data using the atomic pair distribution function (PDF) method. A local JT distortion is observed in the insulating phase for all Ca concentrations studied. However, in contrast with earlier local structure studies its magnitude is not constant, but decreases continuously with increasing Ca content. This observation is at odds with a simple small-polaron picture for the insulating state.Comment: 4 pages, 4 figures, submitted to Physical Review Letter