Laboratory measurements of P-wave and S-wave velocities across a surface analog of the continental crust–mantle boundary: Cabo Ortegal, Spain

Eclogite as a seismic marker in subduction channels: Seismic velocities, anisotropy, and petrofabric of Cabo Ortegal eclogite tectonites (Spain)

“…These refl ectors should imprint a penetrative, dipping fabric to seismic-profi le segments up to 0.5 s wide in vertical dimension. Brown et al (2009) calculated refl ection coeffi cients across high-pressure lithological units and modeled a highly refl ective seismic section of Cabo Ortegal. Some of these refl ectors (with calculated refl ection coeffi cients ranging from 0.08 to 0.21) correspond to the eclogitemassif-bounding contacts.…”

Contribution of crystallographic preferred orientation to seismic anisotropy across a surface analog of the continental Moho at Cabo Ortegal, Spain

“…The scale at which compositional banding is developed is important because, in order to image it at a Moho depth of 50 km, the horizontal resolution (Fresnel zone) needed by seismic-refl ection data is ~7 km and the vertical resolution is ~117 m (assuming an average velocity of 7 km/s and a signal frequency of 15 Hz). Brown et al (2009) reported laboratory measurements of P-wave (V p ) and S-wave (V s ) velocities from the surface analog of the continental Moho transition in Cabo Ortegal of northwestern Spain in which there is very little correlation between the degree to which banding is developed and anisotropy. While we recognize the problem of scale between the minicores used in the velocity measurements and that which can be imaged by seismic-refl ection or wide-angle data, this observation suggests that the CPO of the constituent mineral phases may indeed play an important role in generating seismic anisotropy across the Moho transition.…”

“…In this contribution, we focus on the proposed surface analog of the continental Moho that outcrops in the Cabo Ortegal complex of northwestern Spain, particularly in the crustal part of the rock sequence Brown et al, 2009). CPO data of the main mineral phases found in each lithology of the outcropping lower continental crust and from one of the lithologies in the upper mantle have been measured using electron back scatter diffraction (EBSD) techniques .…”

Influence of magnetic fabric anisotropy on seismic wave velocity in paramagnetic granites from NW Himalaya: Results from preliminary investigations

“…They also show a negative correlation between SiO 2 content and Vp/Vs ratio (Fig.4). Silicate rocks usually show an inverse linear relationship between Vp/Vs and SiO 2 content (Punturo et al 2005;Brown et al 2009). As stated earlier, flaky minerals like muscovite, biotite and chlorite are the dominant contributors of magnetic susceptibility in paramagnetic granite.…”