.... The volcanic rocks from Ulleung Island range in composition from trachybasalt to trachyte and contain abundant euhedral pseudomorphic carbonate grains, ulvöspinel-hosted and biotite-hosted carbonate-silicate melt inclusions, and irregular carbonate globules. Integrated petrographic and geochemical studies...

... by the biotite-ilmenite-feldspar-ulvöspinel (KUIlB) mineral assemblages crystallized from hydrated mafic magmas. The magnetite-rutile symplectite may be used as a unique texture indicator of magma hydration in the evolution history of terrestrial, martian, and lunar magmas. Magnetite-rutile symplectites...

... lamellae and among phases forming the NPs support exsolution from magnetite ss , followed by replacement via mineral-buffered reactions. Lattice-scale intergrowths between ulvöspinel and ilmenite within NPs are interpreted as exsolution recording cooling under O 2 -conserving conditions, whereas...

... oxygen atoms per formula unit, and that of matyhite was shown to be trigonal, R 3 c , with a = 10.456 (7) Å, c = 37.408(34) Å, V = 3541.6 (4.8) Å 3 and Z = 6 for 28 oxygen atoms per formula unit. On the basis of their constant association with the grain-boundary assemblage: Fe sulfide + ulvöspinel + Al...

...) titanomagnetite exsolutions into ulvöspinel + magnetite; followed by (IV) sub-solidus re-equilibration in clinopyroxenes and among Fe–Ti oxides + hercynite. Using exact phase boundary theory, pressures of lamellar exsolution within the host diopside are estimated as ~2 GPa with an error of ± ≤1 GPa. The present...

... X 4 . The oxyspinel group (33 species) can be divided into the spinel subgroup 2-3 ( A 2 + B 2 3 + O 4 ) and the ulvöspinel subgroup 4-2 ( A 4 + B 2 2 + O 4 ) , the thiospinel group (20 species) into the carrollite subgroup 1-3.5 ( A 1 + B 2 3.5 + S 4 ) and the linnaeite subgroup 2-3 ( A 2 + B 2 3...

... clinopyroxenes; feldspars (K-feldspar, Ba-K-feldspar and Na-feldspar) and spinels (chromite-magnetite and qandilite-ulvöspinel-franklinite). These dykes have undergone diverse and significant degrees of deuteric alteration as shown by the formation of secondary phases such as: titanite, allanite, hydro-zircon...

..., kuratite coexisting with Al, Ti-bearing hedenbergite, ulvöspinel, iron-sulfide, tsangpoite, Ca-rich fayalite and kirschsteinite in D'Orbigny angrite most probably was formed at >1000°C by rapid cooling of an interstitial melt, which is subsilicic, almost Mg-free but enriched in Al-P-Ca-Ti-Fe. 21 06...

... dominant exsolution phases in the Ti-rich magnetite, whereas the ulvöspinel phase is barely found. The ilmenite exsolution may have different origins: (1) the cloth-texture lamellae primarily exsolved as ulvöspinel, which was oxidized to ilmenite later at <600 °C; (2) most of the trellis- and sandwich...

... ( Serneels and Perret 2003 ). XRD results show a complex mixture of iron oxides (wüstite, magnetite, hematite), silicates (fayalite, forsterite, kirschsteinite, wollastonite), spinel (hercynite, ulvospinel), amorphous material and alteration products [goethite, lepidocrocite, akaganeite, gypsum...

... ülvospinel contents. * E-mail: pvburger@unm.edu Manuscript handled by Don Baker 02 10 2014 20 1 2015 © 2015 Mineralogical Society of America 2015 Spinel crystal chemistry partitioning vanadium chromium Invited Centennial article Spinels are a common accessory...

... have been approved: ahrensite, brunogeierite, chromite, cochromite, coulsonite, cuprospinel, filipstadite, franklinite, gahnite, galaxite, hercynite, jacobsite, magnesiochromite, magnesiocoulsonite, magnesioferrite, magnetite, manganochromite, qandilite, ringwoodite, spinel, trevorite, ülvospinel...

...Ferdinando Bosi; Ulf Hålenius; Henrik Skogby Abstract Five spinel single-crystal samples within the ulvöspinel-qandilite series [(Fe 2− x Mg x )TiO 4 , 0.15 < x < 0.94] were synthesized and structurally and chemically characterized by X-ray diffraction and electron microprobe techniques. Site...

...G. Diego Gatta; Ferdinando Bosi; Garry J. McIntyre; Ulf Hålenius Abstract A single-crystal neutron diffraction study of a synthetic ulvöspinel sample of composition Fe 3+ 0.40 Fe 2+ 1.80 Ti 0.80 O 4 was performed to investigate the static positional disorder at the octahedrally coordinated M site...

... silicate matrix. Sulfide spheroids (either associated with oxides or separated from them) are changed by dissemination and nests. The chemical compositions of both oxides and sulfides are correlated with the petrochemical types of rocks. Chrome-spinels or chrome-enriched ulvospinels crystallize first...

...Kristina I. Lilova; Carolyn I. Pearce; Christopher Gorski; Kevin M. Rosso; Alexandra Navrotsky Abstract The thermodynamics of mixing and its dependence on cation distribution in the Fe 3 O 4 –Fe 2 TiO 4 (magnetite-ulvöspinel) spinel solid solution were studied using high-temperature oxide melt...

... is buffered by the nepheline-albite equilibrium. In these situations, AUNIlF is stable at oxygen fugacities ≥ −1.15 (ΔFMQ). At values below a SiO 2 / a Fa ~0.77, the AUNIlF equilibrium is shifted to lower oxygen fugacities and ilmenite becomes unstable relative to ulvøspinel. Analogous to the construction...