The measured inwards motion of Phobos provides a constraint on the tidal dissipation factor, Q, within Mars. We model viscoelastic dissipation inside a convective Mars using a modified Burgers model based on laboratory experiments on anhydrous, melt-free olivine. The model tidal Q is highly sensitive to the mantle potential temperature and grain size assumed, but relatively insensitive to the b...

Estimates of the chemical composition of the bulk (entire) Moon fall into two drastically different categories. One group of estimates claims that the Moon is enriched in refractory elements (those that boil at high temperatures, such as calcium and aluminum) by about 50% compared to Earth. The other group claims that the abundances of refractory elements are the same in the Earth and Moon. Two...

We examine the implications of new 182W and 142Nd data for Mars and the Moon for the early evolution of the Earth. The similarity of 182W in the terrestrial and lunar mantles and their apparently differing Hf/W ratios indicate that the Moon-forming giant impact most probably took place more than 60Ma after the formation of calcium-aluminium-rich inclusions (4.568Gyr). This is not inconsistent w...

Major, trace element, and Nd–Sr–Pb isotopic compositions of mantle xenolith-bearing Cenozoic basalts in southeastern China are measured to provide an insight into the nature of their mantle sources and processes. Application of a modified Ž . dynamic melting inversion DMI method presented here to SE China basalts suggests that Nushan and Fangshan basalts are formed by 4–11% partial melting of a...

There is growing evidence that the budget of Pb in mantle peridotites is largely contained in sulfide, and that Pb partitions strongly into sulfide relative to silicate melt. In addition, there is evidence to suggest that diffusion rates of Pb in sulfide (solid or melt) are very fast. Given the possibility that sulfide melt ‘wets’ sub-solidus mantle silicates, and has very low viscosity, the im...

Introduction Seismological observations provide information about the properties and processes of the Earth’s interior in the form of profiles of density and velocity as a function of depth. Seismic tomography on a global scale reveals lateral variations in compressional (P) and shear (S) wave velocities and densities at various depths of the Earth’s interior, reflecting differences in chemical...

[1] The pyrolite model is one of the possible compositions of the Earth’s lower mantle. The lower mantle’s composition is generally modelled by comparing seismic observations with mineral physics data of possible lower mantle end-member phases. Here, we report the compression behavior of a natural KLB-1 peridotite (a representative composition of the pyrolite model) in a quasihydrostatic enviro...

Two underground detectors, in Japan and Italy, are currently recording interactions of highly penetrating particles called geoneutrinos, which are naturally produced inside the Earth. By measuring the geoneutrino flux, these pioneering projects along with several other projects that are being planned are advancing constraints on the contribution of radioactive elements to Earth’s heat budget in...

Introduction: Siderophile element concentrations in planetary basalts and mantle samples have been used to estimate conditions of core formation for many years and have included applications to Earth, Moon, Mars and asteroid 4 Vesta [1]. For Earth, we have samples of mantle and a diverse collection of mantle melts which have provided a mature understanding of the how to reconstruct the concentr...

a r t i c l e i n f o a b s t r a c t Keywords: viscosity lower mantle mantle plume elasticity spin transition A proper determination of the lower-mantle viscosity profile is fundamental to understanding Earth geodynamics. Based on results coming from different sources, several models have been proposed to constrain the variations of viscosity as a function of pressure, stress and temperature. ...