The surface of Mars consists of an old, heavily cratered and elevated southern hemisphere and younger, resurfaced and depressed northern hemisphere, a feature often termed the crustal dichotomy. The global crustal structure [Zuber et al., 2000] revealed by topography and gravity data from the Mars Global Surveyor spacecraft, and the possible late formation of the boundary zone between the hemis...

We utilize earthquake recordings at two broadband seismographs located on the coast of the Gulf of Mexico to estimate Q of the mantle wedge. From the data at a station situated in the Laguna Verde nuclear power plant (LVIG), about 100 km northwest of Veracruz, and at the eastern edge of the Mexican Volcanic Belt, we estimate an upper bound of shear-wave Q of the mantle wedge, Q( f ) 120f 0.75 (...

BACKGROUND AND PURPOSE The properties of the cement mantle around a prosthesis are important. We investigated whether the surgical approach to the hip influences the quality and thickness of the cement mantle when using a straight femoral stem design. METHODS In a consecutive multi-surgeon series, we reviewed the radiographs of 270 patients after cemented Exeter total hip arthroplasty. 135 st...

Introduction Ocean island basalts (OIB) are thought to sample the Earth’s deep mantle, whereby thermochemical plumes entrain lower mantle material and bring it to the surface where it erupts. By measuring the isotopic compositions of global OIB—which record the isotopic compositions of OIB mantle sources—geochemists can “map” the isotopic heterogeneity of the Earth’s deep mantle (e.g., Gast et ...

Study of commercially produced volcanic CO2 gas associated with the Colorado Plateau, USA, has revealed substantial new information about the noble gas isotopic composition and elemental abundance pattern of the mantle. Combined with published data from mid-ocean ridge basalts, it is now clear that the convecting mantle has a maximum (20)Ne/(22)Ne isotopic composition, indistinguishable from th...

Seismic refraction, gravity, phase velocity, and magnetic data, coupled with the geologic record, are all approximately satisfied by the structure shown in Fig. 9. A 20-kilometer crust under the Coast Ranges and Great Valley thickens to more than 30 kilometers under the Sierra Nevada and parts of the Basin and Range province; this whole area is underlain by an anomalous upper mantle with a velo...

The components of rock-forming and accessory minerals of the upper mantle, transition zone and lower mantle rocks have been involved into the processes of diamond genesis. Through their dissolving in primary carbonate melts, the mantle minerals have turned into components of the parental silicate-(±oxide)carbonate-carbon melts-solutions for diamonds and co-crystallized paragenetic minerals. The...

Sr, Nd and Pb isotope data for basalts from spreading axes and off-axis volcanoes near the Pacific–Antarctic risecrest, from Vacquier transform to just south of Udintsev transform, reveal an isotopically heterogeneous upper mantle. The Ž . isotopic composition of the mantle is represented by three end-members: 1 the ‘depleted’ source of the bulk of Pacific Ž . Ž . normal-type mid-ocean ridge ba...

The mantle plume hypothesis is widely accepted for the formation of large igneous provinces and many modern day hotspot volcanoes. Petrologic models suggest that plume-derived melts originate at high mantle temperatures (>1500 °C) relative to those generated at ambient midocean ridge conditions (~1350 °C). Earth’s mantle has also appreciably cooled during its history due to heat loss and decrea...