a r t i c l e i n f o Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic gneisses that are less dense than peridotite but more dense than the uppe...

CRUSTAL-CONTAMINATED MELTS ? J. A. Barrat 1 , A. Yamaguchi, R.C. Greenwood, M. Bohn, J. Cotten, M. Benoit and I. A. Franchi, UBO-IUEM, CNRS-UMR 6538, Place Nicolas Copernic, F-29280 Plouzané Cedex ([email protected]), Antarctic Meteorite Research Center, National Institute of Polar Research, 1-9-10 Kaga, Itabashi, Tokyo 173-8515, Japan. PSSRI, Open University, Walton Hall, Milton Keynes MK7 ...

It is generally accepted that continental subduction and crustal exhumation play an important role in the evolution of many orogenic belts. A variety of geological evidence suggests that continental crust is occasionally subducted to depths of tens to perhaps 150 km (e.g. Chopin, 1984; Dewey et al., 1993; Matte et al., 1997). Recently, a series of simulations (Chemenda, 1993; Chemenda et al., 1...

[1] Noble gas concentrations and isotopic ratios are presented for 38 deep ( 0.5–3.6 km) brine samples in the Michigan Basin. These brine samples clearly show the presence of an important crustal component of He, Ne, Ar, and Xe. Both Arcrust and Xecrust display the presence of a strong vertical gradient along the sedimentary strata of the basin. We show that the in situ production for these two...

The formation of the lunar farside highlands has long been an open problem in lunar science. We show that much of the topography and crustal thickness in this terrain can be described by a degree-2 harmonic. No other portion of the Moon exhibits comparable degree-2 structure. The quantified structure of the farside highlands unites them with the nearside and suggests a relation between lunar cr...

Using an inversion strategy based on adjoint methods, we developed a three-dimensional seismological model of the southern California crust. The resulting model involved 16 tomographic iterations, which required 6800 wavefield simulations and a total of 0.8 million central processing unit hours. The new crustal model reveals strong heterogeneity, including local changes of +/-30% with respect t...

[1] Integration of stress indicator data, gravity data, crustal kinematics data, and analysis of topography and recent vertical motions demonstrates the occurrence of consistently oriented spatial patterns of large-scale Alpine to recent intraplate deformation in Iberia. The inferred upper crustal and lithospheric deformation patterns and the timing of the associated expressions at or near the ...

Energy-time dispersed electron signatures are observed by the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission in the vicinity of strong Martian crustal magnetic fields. Analysis of pitch angle distributions indicates that these dispersed electrons are typically trapped on closed field lines formed above strong crustal magnetic sources. Most of the dispersed electron signatures are charac...

Mineral physics observations suggest that distinct density and rheological differences exist between the crustal component of oceanic lithosphere and the underlying mantle. We have conducted numerical experiments to investigate the influence of both density and viscosity on the effectiveness of recycling of oceanic crust into the lower mantle. Confirming previous results, the density inversion ...

Structural and tectonic patterns mapped in Fortuna Tessera are interpreted to reflect a change in the style and intensity of deformation from east to west, beginning with simple tessera terrain at relatively low topographic elevations in the east and progressing through increasingly complex deformation patterns and higher topography to Maxwell Montes in the west. These morphologic and topograph...