R-modes in neutron stars with crusts are damped by viscous friction at the crust-core boundary. The magnitude of this damping, evaluated by Bildsten and Ushomirsky (BU) under the assumption of a perfectly rigid crust, sets the maximum spin frequency for a neutron star spun up by accretion in a Low-Mass X-ray binary (LMXB). In this paper we explore the mechanical coupling between the core r-mode...

Since heavy metals are considered as one of the major pollutants threatening, the main goal of this study was to bring out the concentrations of Pb, Zn and Mn in the surface sediments off Bushehr in the Persian Gulf. For this purpose, after collection of samples, the concentrations of the three metals in surface sediments were measured through the atomic absorption. The results were compared wi...

Authigenic seafl oor carbonate crusts include fenestrate microbialite, thrombolite, and four types here designated: Fine-grained Crust, Sparry Crust, Hybrid Sparry Fine-grained Crust, and Sparry Crust plus Coarse Grains. Each of the latter four types includes at least some layered examples that have generally been regarded as stromatolites. Recognition and interpretation of these various deposi...

Abstract Metamorphism of dry, lower crust within orogens is often localized in shear zones composed mechanically weaker rocks 1–4 . Several field-based studies suggest zone development preceded by brittle faults which provide the fluid pathways required for metamorphism and weakening 4–12 However, a unifying model couples long-term geological deformation to migration metamorphic reactions does ...

In modern plate tectonic regimes, continental crust is generated above subduction zones in magmatic island arcs. Models for growth—largely based on the modeling of geochemical processes that can transform mantle melts into intermediate composition bulk crust—have been hampered by a lack definitive geochronology, which could clarify temporal emplacement igneous rocks at base arc crust. The Kohis...

We collected continuous seismic data recorded between 2007 and 2010 by 208 broadband stations from the Chinese Provincial Digital Seismic Networks, A Seismic Collaborative Experiment of Northern Tibet, and the Northeastern Tibet Seismic experiment. Cross correlations of vertical component records are computed to extract the Rayleigh wave empirical Green’s functions. Group and phase velocities a...

Numerical experiments reproduce the fundamental architecture of magma-poor rifted margins such as the Iberian or Alpine margins if the lithosphere has a weak mid-crustal channel on top of strong lower crust and a horizontal thermal weakness in the rift center. During model extension, the upper crust undergoes distributed collapse into the rift center where the thermally weakened portion of the ...