Ferric iron stabilization at deep magma ocean conditions.

FeO produced in a deep magma ocean in equilibrium with core-destined alloy sets the early redox budget and atmospheric composition of terrestrial planets. Previous experiments (≤28 gigapascals) and first-principles calculations indicate that a deep terrestrial magma ocean produces appreciable Fe but predict Fe/ΣFe ratios that conflict by an order of magnitude. We present Fe/ΣFe of glasses quenched from melts equilibrated with Fe alloy at 38 to 71 gigapascals, 3600 to 4400 kelvin, analyzed by synchrotron Mössbauer spectroscopy.

Early volatile depletion on planetesimals inferred from C-S systematics of iron meteorite parent bodies.

During the formation of terrestrial planets, volatile loss may occur through nebular processing, planetesimal differentiation, and planetary accretion. We investigate iron meteorites as an archive of volatile loss during planetesimal processing. The carbon contents of the parent bodies of magmatic iron meteorites are reconstructed by thermodynamic modeling.

Hydrogen Incorporation in Plagioclase.

We conducted experiments at high pressure () and temperature () to measure hydrogen solubility in plagioclase (Pl) with a range of compositions (An to An). Experiments were run at 700-850 °C, 0.5 GPa, and close to either the Ni-NiO (NNO) or iron-wüstite (IW) oxygen buffers.

Predictors for Target Vessel Failure after Recanalization of Chronic Total Occlusions in Patients Undergoing Surveillance Coronary Angiography.

(1) Background: Knowledge about predictors for the long-time patency of recanalized chronic total coronary occlusions (CTOs) is limited. Evidence from invasive follow-up in the absence of acute coronary syndrome (routine surveillance coronary angiography) is scarce. (2) Methods: In a monocentric-retrospective analysis, we obtained baseline as well as periprocedural data of patients undergoing routine invasive follow-up.

Hydrogen isotopic evidence for early oxidation of silicate Earth.

The Moon-forming giant impact extensively melts and partially vaporizes the silicate Earth and delivers a substantial mass of metal to Earth's core. The subsequent evolution of the magma ocean and overlying atmosphere has been described by theoretical models but observable constraints on this epoch have proved elusive. Here, we report thermodynamic and climate calculations of the primordial atmosphere during the magma ocean and water ocean epochs respectively and forge new links with observations to gain insight into the behavior of volatiles on the Hadean Earth.

Tracing the ingredients for a habitable earth from interstellar space through planet formation.

We use the C/N ratio as a monitor of the delivery of key ingredients of life to nascent terrestrial worlds. Total elemental C and N contents, and their ratio, are examined for the interstellar medium, comets, chondritic meteorites, and terrestrial planets; we include an updated estimate for the bulk silicate Earth (C/N = 49.0 ± 9.

Within-lesion differences in quantitative MRI parameters predict contrast enhancement in multiple sclerosis.

Purpose: To investigate the relationship between quantitative magnetic resonance imaging (qMRI) and contrast enhancement in multiple sclerosis (MS) lesions. We compared maps of T1 relaxation time, proton density (PD), and magnetization transfer ratio (MTR) between lesions with and without contrast enhancement as quantified by the amount of T1 shortening postcontrast agent (CA).

Materials And Methods: In 17 patients with relapsing-remitting MS (RRMS), 15 with progressive MS (PMS), and 17 healthy controls, T1, PD, and MTR were measured at 3T and T1-mapping was repeated after CA administration.

Carbon-dioxide-rich silicate melt in the Earth's upper mantle.

The onset of melting in the Earth's upper mantle influences the thermal evolution of the planet, fluxes of key volatiles to the exosphere, and geochemical and geophysical properties of the mantle. Although carbonatitic melt could be stable 250 km or less beneath mid-oceanic ridges, owing to the small fraction (∼0.03 wt%) its effects on the mantle properties are unclear.

Structure and speciation in hydrous silica melts. 2. Pressure effects.

The effect of pressure on structure and water speciation in hydrated liquid silica is examined over a range of temperatures and compositions. The Feuston-Garofalini (FG) potential is used in isobaric-isothermal Monte Carlo simulations carried out at four pressures (0.25, 1.

Structure and speciation in hydrous silica melts. 1. Temperature and composition effects.

Monte Carlo simulations were used to investigate the phase behavior of hydrated liquid silica as a function of temperature and overall water mole fraction, x w. Simulations using the Feuston-Garofalini potential were performed in the isobaric-isothermal ensemble at p = 1 GPa for 15 temperatures (2000 < or = T < or = 9000 K) and 25 compositions (0.0 < or = x w < or = 0.

Melting in the Earth's deep upper mantle caused by carbon dioxide.

The onset of partial melting beneath mid-ocean ridges governs the cycling of highly incompatible elements from the mantle to the crust, the flux of key volatiles (such as CO2, He and Ar) and the rheological properties of the upper mantle. Geophysical observations indicate that melting beneath ridges begins at depths approaching 300 km, but the cause of this melting has remained unclear. Here we determine the solidus of carbonated peridotite from 3 to 10 GPa and demonstrate that melting beneath ridges may occur at depths up to 330 km, producing 0.

Earth science: a wet mantle conductor?

The suggestion that the transition zone of Earth's mantle (410-670 km in depth) is enriched in water is of great possible significance to the geodynamics and geochemistry of Earth's interior, as well as for the role of the mantle in the global water cycle. Huang et al. compare the effect of water on electrical conductivities of transition-zone phases to electromagnetic and magnetotelluric soundings of the mantle beneath the North Pacific and conclude that the transition zone contains between 1,000 and 2,000 p.