The study, published in Earth and Planetary Science Letters on April 14, was supported by the National Natural Science Foundation of China, PIFI from Chinese Academy of Sciences (CAS) and NERC Grants. The width of the phase loop was negligible for water contents less than about 1000 ppm, but then grew rapidly to become about 10 km wide, before shrinking again as the water content approaches ringwoodite saturation. This variation on depth was relatively small compared to seismically observed variations in the 660 km discontinuity of around 35 km and so water alone could not account for the observed 660 km discontinuity topography.įurthermore, this study demonstrated that the addition of water caused a large broadening of the three-phase loop (ringwoodite + bridgmanite + MgO) through the development of post-spinel transition. 1 wt.% water increased the depth of phase transition onset by about 8 km. On the other hand, water had a moderate effect on its depth. ![]() The results indicated that the water only had a very small effect on the Clapeyron slope of the post-spinel transition. John Brodholt from University College London (UCL), investigated the effect of water on the post-spinel transition at high temperatures and pressures. ZHANG Feiwu from the Institute of Geochemistry of the Chinese Academy of Sciences (IGCAS), in collaboration with Prof. Joshua Muir, the postdoctoral researcher, and the team leader Prof. According to recent studies, the transition zone may contain significant amounts of water, and thus understanding the effect of water on the post-spinel transition is important to determine its properties.ĭr. One important parameter that can potentially affect the post-spinel transition is hydration. It is considered to be caused by the transformation of ringwoodite to bridgmanite and MgO (post-spinel transition). The anomalies may not have been seen clearly in the reflectivity and similarity data calculated without the application of dip-steering.The seismic discontinuity that occurs at an average depth of 647-654 km, usually called the 660 km seismic discontinuity, is the boundary between the transition zone and the lower mantle. The attribute data detected discrete zones of dip and similarity anomalies, trending WNW-ESE, that represented the location of discontinuities in the area. A multitrace similarity attribute volume was then calculated with the reflectivity and background dip-steering data as the input. The data were further improved by calculating two additional generations of dip volumes representing localized and subregional structural dips referred to as the "detailed" and "background" steering volumes, respectively. Firstly, the dip and azimuth of seismic traces in the data were calculated in a volume referred to as the "raw steering" data. The anomalies may not have been seen clearly in the reflectivity and similarity data calculated without the application of dip-steering.ĪB - Techniques for detecting faults have been applied to a 3D seismic volume acquired in the outer fold and thrust belt in the deep-water Niger Delta. A boundary between seismic layers of the earth. ![]() (geophysics) A surface at which velocities of seismic waves change abruptly. ![]() N2 - Techniques for detecting faults have been applied to a 3D seismic volume acquired in the outer fold and thrust belt in the deep-water Niger Delta. T2 - Case study using deep-water Niger Delta 3D seismic data T1 - Application of volumetric seismic discontinuity attribute for fault detection
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |