Measurements of carbon dioxide and heat fluxes during monsoon-2011 season over rural site of India by eddy covariance technique

An increase in carbon dioxide (CO₂) concentrations in the atmosphere due to anthropogenic activities is responsible for global warming and hence in recent years, CO₂ measurement network has expanded globally. In the monsoon season (July–September) of year 2011, we carried out measurements of CO₂ and water vapour (H₂O) concentrations along with wind and air temperature over a tropical site in south-east India having rural topography. To collect these observations, the instrumentations used were the sonic anemometer for wind and temperature, and the open path H₂O/CO₂ infrared gas analyzer for CO₂ and H₂O concentrations. Using these observations, we explored the diurnal variability of CO₂ flux along with sensible and latent heat. The CO₂ flux was positive during night-time and negative during daytime and in phase with convective instability. The CO₂ flux relationships with the meteorological parameters such as wind speed, temperature and heat fluxes have been analysed. The seasonal (monsoon) half hour mean of CO₂ flux which was ?3.55 μmol m^???2 s^???1 indicated the experimental site as a CO₂ sink region (net seasonal uptake). An increase in CO₂ concentrations during weekends was not observed due to unavailability of heavy vehicular traffic.     

A “tsunami” in the protoplanetary disk of SV Cep

The results of ~15 years of photometric observations of the UX Ori star SV Cep in the near-infrared (JHKL) are presented. They demonstrate the presence of a cyclic component with a period of ~7 years in the variations of the IR fluxes. This is clearly seen in all four IR bands, but is absent in the optical. The variation amplitude is highest in the K band: ΔK ≈ 0.68 ^m . The shape of the variations differs slightly in the transition from J to L. However, it is reproduced with good accuracy during two cycles, suggesting a periodic process is observed. If the periodic perturbations in the circumstellar disk of SV Cep are due to a companion’s orbitalmotion, the orbital semi-major axis should be ~5AU, foramass of SVCep of 2.6M _⊙. The absence of a seven-year period in the optical light curve of SV Cep means that the observed period cannot be due to variations in the circumstellar extinction. The IR brightness variations could be due to the companion’s motion along an eccentric orbit, resulting in a periodic modulation of the rate of accretion onto the star.     

Directional dependence of P- and S-wave propagation and polarization in foliated rocks from the Kola superdeep well: Evidence from laboratory measurements and calculations based on TOF neutron diffraction

We have measured P- and S-wave velocities on two amphibolite and two gneiss samples from the Kola superdeep borehole as a function of pressure (up to 600 MPa) and temperature (up to 600 °C). The velocity measurements include compressional (Vp) and shear wave velocities (Vs1, Vs2) propagating in three orthogonal directions which were in general not parallel to inherent rock symmetry axes or planes. The measurements are accompanied by 3D-velocities calculations based on lattice preferred orientation (LPO) obtained by TOF (Time Of Flight) neutron diffraction analysis which allows the investigation of bulk volumes up to several cubic centimetres due to the high penetration depth of neutrons. The LPO-based numerical velocity calculations give important information on the different contribution of the various rock-forming minerals to bulk elastic anisotropy and on the relations of seismic anisotropy, shear wave splitting, and shear wave polarization to the structural reference frame (foliation and lineation). Comparison with measured velocities obtained for the three propagation directions that were not in accordance with the structural frame of the rocks (foliation and lineation) demonstrate that for shear waves propagating through anisotropic rocks the vibration directions are as important as the propagation directions. The study demonstrates that proper measurement of shear wave splitting by means of two orthogonal polarized sending and receiving shear wave transducers is only possible when their propagation and polarization directions are parallel and normal to foliation and lineation, respectively.     

The influence of the Sabatayn Evaporites on the hydrocarbon prospectivity of the Eastern Shabwa Basin, Onshore Yemen

The Shabwa Basin is the northeastern extension of the Marib-Al Jawf-Shabwa system of Mesozoic grabens, located onshore in the Republic of Yemen. An evaporitic sequence with an estimated maximum depositional thickness of 300 metres was deposited during the Tithonian. It is designated the Sabatayn Formation and exerts significant control on most of the play elements in the principal hydrocarbon play systems anticipated in the northeastern part of the basin. Migration of hydrocarbons from pre-salt source rocks into intra-and post-salt reservoirs is restricted by the evaporites. Localised heat flow perturbations introduced by the salt, increase the maturity of post-salt source rocks. Post and intra-salt reservoirs are structured by listric faulting on a salt detachment, salt pillowing due to post-depositional loading, by local salt dissolution and by late folding due to gravity sliding of the post-salt section on a salt detachment. Early dissolution and reprecipitation of salt is responsible for occlusion of porosity in intra-salt clastic reservoirs.     

Archean regional transpression and paleomagnetism in northwestern Ontario, Canada

The Archean metamorphic rocks of the Superior province of the Canadian Shield occur in lithologically defined belts or subprovinces. The tectonically more stable interiors of belts possess consistent primary components of magnetic remanence. In the case of the Quetico belt, these stable directions are tightly grouped about 005°/55° with some minor dispersion and most were acquired during the cooling that followed syntectonic recrystallisation.

This study examines the directions of primary remanence components for rocks along the margins of the Quetico belt, within 4 km of the strongly deformed vertical, ENE-trending boundaries. The boundaries are known to have experienced dextral transpression involving penetrative single-phase deformation which out-lasted metamorphism. Within a few kilometres of the belt boundaries, the primary remanence components are re-distributed along a vertical ENE-trending, great-circle girdle which is nearly parallel to the plane of transpressive shear and regional schistosity. It is suggested that the effects of transpression have mechanically deflected the components of primary remanence toward this plane.