Based on a pyrolitic compositional model, the lower mantle is mainly made of ferropericlase, aluminous silicate perovskite, and calcium perovskite. Silicate perovskite transforms into silicate post-perovskite structure just above the core-mantle region, the D" layer. The existence of iron in the lower-mantle minerals can affect a broad spectrum of the minerals’ physical and chemical properties....

We have discovered an isotopically highly anomalous MgSiO3 grain in the ungrouped carbonaceous chondrite Acfer 094 with a perovskite-like crystal structure resembling the dominant high-pressure mineral of the Earth’s lower mantle. Oxygen isotopic ratios of the silicate grain are O/ O p (4.91 0.36) # 10 (12 times the 3 solar value) and O/O p (1.36 0.19) # 10 (0.4 times the solar value). This sig...

Pyrosmalite-(Fe), ideally Fe(II) (8)Si(6)O(15)(OH,Cl)(10) [refined composition in this study: Fe(8)Si(6)O(15)(OH(0.814)Cl(0.186))(10)·0.45H(2)O, octa-iron(II) hexa-silicate deca-(chloride/hydroxide) 0.45-hydrate], is a phyllosilicate mineral and a member of the pyrosmalite series (Fe,Mn)(8)Si(6)O(15)(OH,Cl)(10), which includes pyrosmalite-(Mn), as well as friedelite and mcgillite, two polytypes...

Spectroscopic observations at 2.4 – 45 μm of the young supernova remnant Cas A with the Infrared Space Observatory (ISO) Short Wavelength Spectrometer (SWS) reveal strong emission lines of O, Ne, Si, S, and Ar. These lines are observed at high velocities (several 10 km s), and are therefore associated with the supernova ejecta known as the fast-moving knots (FMKs). Continuum emission from dust ...

Recent regulations are encouraging the replacement of older types of man-made mineral fibre by more soluble and, thus, less biopersistent compositions. In order for there to be any health benefits from this policy and to gain maximum benefit from such substitutions, the use of the new materials should not increase exposure. The work reported here was undertaken to investigate the use of new hig...

New high-resolution spectral and morphologic imaging of deposits on walls and floor of Ius Chasma extend previous geomorphic mapping, and permit a new interpretation of aqueous processes that occurred during the development of Valles Marineris. We identify hydrated mineralogy based on visible-near infrared (VNIR) absorptions. We map the extents of these units with CRISM spectral data as well as...

One of the weaknesses of using receptor models to apportion the sources of ambient particulate matter is their inability to separate collinear sources such as different types of geological material. In order to develop a methodology to separate the different geological source contributions an ambient monitoring and source apportionment study was carried out for the cities of Reno and Sparks, NV...

UNLABELLED Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus. OBJECTIVE The aim of this study was to evaluate biocompatibility and bioactivity of these two calcium silicate-based sealers in culture of human dental pulp cells (hDPCs). MATERIAL AND METHODS The cells were isolated from t...