Fumarolic pipes in the Tshirege Member of the Bandelier Tuff on the Pajarito Plateau, Jemez Mountains, New Mexico     

Florie A. Caporuscio  Jamie N. Gardner  Emily S. Schultz-Fellenz  Richard E. Kelley 《Bulletin of Volcanology》2012,74(5):1023-1037

The objective of this study is to demonstrate the relationships among devitrification, vapor phase alteration, localization of gas emanations into fumarolic pipes, and initial deformation of the ash flow sheet during cooling and lithification. Utilizing a unique and temporary exposure of the Tshirege Member of the Bandelier Tuff near Los Alamos, New Mexico, we identify several zones of distinctly preserved fossil fumarolic activity. The fumarolic zones vary in width from a few centimeters to more than a meter. Almost ubiquitously, these zones demonstrate fines-depletion, induration of the margins, upward-flaring geometries, and intense fracturing of overlying geologic units. The fumaroles were preferentially located on post welding, early formed cooling joints that vented to the surface after the vapor phase alteration stage. The pipes were regularly spaced at distances of approximately 4.5?m (N–S) to 7?m (E–W). In turn the pipes were covered by a surge deposit and overlying tuff which rapidly lithified. The overlying tuff was then brecciated during continued fumarolic pipe emissions. Geochemical evaluations confirm the presence of high-temperature mineral (scapolite) indicative of transport of hot volcanic gases through these zones. The pipe centers and walls are depleted in SiO₂, and enriched in Al₂O₃ and FeO. The overlying tuff breccia zones are enriched in Al₂O₃, FeO and MgO, and depleted in SiO₂, NaO, and K₂O. From comparison to other ignimbrite cooling histories, the fissures, fumaroles, and structures observed all likely formed in the first few decades after the deposition of the upper Tshirege subunits. This may have significant implications as to timing of initial cooling fractures and subsequent consolidation of gas emission pathways.  相似文献   

Effect of Biochar and Amendments on Pb and As Phytotoxicity and Phytoavailability in a Technosol     

Romain Nandillon  Florie Miard  Manhattan Lebrun  Marie Gaillard  Stphane Sabatier  Sylvain Bourgerie  Fabienne Battaglia‐Brunet  Domenico Morabito 《洁净——土壤、空气、水》2019,47(3)

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Trace element crystal chemistry of mantle eclogites     

Florie A. Caporuscio  Joseph R. Smyth 《Contributions to Mineralogy and Petrology》1990,105(5):550-561

Rare earth element (REE) concentrations have been measured using instrumental neutron activation analysis on clean separates of primary minerals from 11 eclogite samples from the Bobbejaan and Roberts Victor kimberlites, South Africa. Samples were selected to reflect minimal secondary alteration and represent a broad range of eclogite compositions from coesiteand corundum-grospydites through magnesian bimineralic eclogites. Correlations between REE concentrations and major-element compositions suggest that garnet and clinopyroxene crystal chemistry are the dominant control on REE distribution and that these approach solidstate equilibrium distributions. Reconstructed wholerock REE concentration variation with whole-rock major-element compositions are consistent with an origin by high-pressure igneous fractionation followed by reequilibration to lower temperatures at pressures in excess of three GPa.  相似文献