Paleomagnetic and rock magnetic study of the Yaxcopoil‐1 impact breccia sequence,Chicxulub impact crater (Mexico)     

J. Urrutia‐Fucugauchi  A. M. Soler‐Arechalde  M. Rebolledo‐Vieyra  P. Vera‐Sanchez 《Meteoritics & planetary science》2004,39(6):843-856

Abstract— Results of a detailed paleomagnetic and rock magnetic study of samples of the impact breccia sequence cored in the Yaxcopoil‐1 (Yax‐1) borehole between about 800 m and 896 m are presented. The Yax‐1 breccia sequence occurs from 794.63 m to 894.94 m and consists of redeposited melt‐rich, clast‐size sorted, fine‐grained suevites; melt‐rich, no clast‐size sorting, medium‐grained suevites; coarse suevitic melt agglomerates; coarse melt‐rich heterogeneous suevites; brecciated suevites; and coarse carbonate and silicate melt suevites. The low‐field susceptibility ranges from ?0.3 to 4018 times 10^?6 SI, and the NRM intensity ranges from 0.02 mA/m up to 37510 mA/m. In general, the NRM intensity and magnetic susceptibility present wide ranges and are positively correlated, pointing to varying magnetic mineral contents and textures of the melt‐rich breccia sequence. The vectorial composition and magnetic stability of NRM were investigated by both stepwise alternating field and thermal demagnetization. In most cases, characteristic single component magnetizations are observed. Both upward and downward inclinations are present through the sequence, and we interpret the reverse magnetization as the primary component in the breccias. Both the clasts and matrix forming the breccia appear to have been subjected to a wide range of temperature/pressure conditions and show distinct rock magnetic properties. An extended interval of remanence acquisition and secondary partial or total remagnetization may explain the paleomagnetic results.  相似文献   

STE-QUEST mission and system design     

Gerald Hechenblaikner  Marc-Peter Hess  Marianna Vitelli  Jan Beck 《Experimental Astronomy》2014,37(3):481-501

STE-QUEST is a fundamental science mission which is considered for launch within the Cosmic Vision programme of the European Space Agency (ESA). Its main scientific objectives relate to probing various aspects of Einstein’s theory of general relativity by measuring the gravitational red-shift of the earth, the moon and the sun as well as testing the weak equivalence principle to unprecedented accuracy. In order to perform the measurements, the system features a spacecraft equipped with two complex instruments, an atomic clock and an atom interferometer, a ground-segment encompassing several ground-terminals collocated with the best available ground atomic clocks, and clock comparison between space and ground via microwave and optical links. The baseline orbit is highly eccentric and exhibits strong variations of incident solar flux, which poses challenges for thermal and power subsystems in addition to the difficulties encountered by precise-orbit-determination at high altitudes. The mission assessment and definition phase (Phase-A) has recently been completed and this paper gives a concise overview over some system level results.  相似文献   

On covariances of eigenvalues and eigenvectors of second-rank symmetric tensors     

Tomás Soler  Boudewijn H. W. van  Gelder 《Geophysical Journal International》1991,105(2):537-546

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On differential scale changes and the satellite Doppler system z-shift   总被引：2，自引：0，他引：2  

Tomás Soler  Boudewijn H. W. van  Gelder 《Geophysical Journal International》1987,91(3):639-656

An often neglected but important role is played by differential scale changes in transforming geodetic datums. A rigorous account of scale variations in any transformation involving reference ellipsoids and its effects on geodetic heights is essential. This role provides a plausible explanation for the reported z -shift between the Doppler defined terrestrial systems and the satellite laser ranging frames.  相似文献   

GPS & GLONASS Current Bibliography     

Tomás Soler 《GPS Solutions》2001,5(1):71-73

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Eruptive response of oceanic islands to giant landslides: New insights from the geomorphologic evolution of the Teide-Pico Viejo volcanic complex (Tenerife, Canary)     

Thomas Boulesteix  Anthony Hildenbrand  Pierre-Yves Gillot  Vicente Soler 《Geomorphology》2012,138(1):61-73

Large sector collapses are a major component of oceanic islands evolution. Here we show that voluminous events such as the Icod landslide on Tenerife (Canary Islands) cause dramatic changes on the magma feeding system and control the subsequent volcanic and geomorphologic evolution of the eruptive complex over a period of more than 150 kyr. Instantaneous unloading by the Icod landslide is marked by the development of a large phonolitic explosive eruption dated at 175 ± 3 ka and interpreted as reflecting the immediate emptying of a shallow pre-existing magma chamber. Geochronological, geomorphological and geochemical analyses, carried out on the post-landslide volcanic succession sampled in a 4.4 km-long underground water-recovery gallery, provide further evidence for an enhanced extrusion of primitive lavas starting in the 10 kyr time interval following the failure. Rapid construction (< 40 kyr) of a thick basaltic volcano in the landslide scar at high eruptive rates (up to 8 km³ kyr⁻¹) increased the lithostatic pressure which then favored the intermittent storage of basic magma under the edifice. This resulted in more episodic construction evidenced by a significant decrease in output rates and the increasing occurrence of lavas with intermediate composition from 117 ± 7 to 52 ± 7 ka. An apparent volcanic gap is observed between 52 ± 7 and 18 ± 1 ka, after which highly differentiated lavas have been dominantly erupted. We propose that part of the gap can be explained by the individualization of a shallow magma reservoir a few kilometers below the base of the Teide volcano. During recent periods, vertical and lateral extrusions of trachytic and phonolitic viscous bodies from this storage area contributed to increase the slope of the main edifice up to 35°, overall favoring its present-day instability.  相似文献   

High CO2 Levels in Boreholes at El Teide Volcano Complex (Tenerife, Canary Islands): Implications for Volcanic Activity Monitoring     

V. Soler  J. A. Castro-Almazán  R. T. Viñas  A. Eff-Darwich  S. Sánchez-Moral  C. Hillaire-Marcel  I. Farrujia  J. Coello  J. de la Nuez  M. C. Martín  M. L. Quesada  E. Santana 《Pure and Applied Geophysics》2004,161(7):1519-1532

Emissions of CO₂ have been known for more than a hundred years as fumarolic activity at the terminal crater of El Teide volcano and as diffuse emissions at numerous water prospection drillings in the volcanic island of Tenerife. Large concentrations of CO₂ (>10% in volume) have been found inside galleries, long horizontal tunnels excavated for water mining. However, CO₂ concentrations of only 2900 ppm have been observed at the surface of the central region of the island (Las Cañadas del Teide caldera). In this work we analysed CO₂ concentrations in the subsurface of Las Cañadas caldera, in an attempt to study the vertical distribution of carbon dioxide and, in particular, the low emissions at the surface. This has been done through a series of 17 vertical profiles in two deep boreholes excavated in the Caldera. We found high levels of CO₂, varying in time from 13 vol% up to 40 vol% in different profiles directly above the water table, while no significant concentrations were detected above the thermal inversion that takes places in both boreholes at approximately 100 m from the water table. Water analyses also showed high dissolved CO₂ levels in equilibrium with the air, and an average 13C value in DIC of +4.7 (PDB), apparently induced by fast CO₂ degassing in the bicarbonated water.  相似文献   

Simulations of minerals using density-functional theory based on atomic orbitals for linear scaling     

M. S.?Craig  M. C.?Warren  M. T.?DoveEmail author  J. D.?Gale  D.?Sanchez-Portal  P.?Ordejon  J. M.?Soler  E.?Artacho 《Physics and Chemistry of Minerals》2004,31(1):12-21

The use of quantum mechanics methods within the formalism of density functional theory requires a method to represent the electron wave functions. We compare the use of strictly localized basis functions based on atomic orbitals with the use of plane waves for the study of mineral properties and behaviour. Strictly localized functions enable the computational resources to scale linearly with the size of the system, whereas plane-wave methods scale more as the cube power of the system size, and for this reason the use of localized functions will be preferred for studies of large sizes. We present test results obtained from studies of cation ordering in spinel, garnet and amphibole phases, the high-pressure displacive phase transition in cristobalite, and the intercalation of organic molecules into pyrophyllite. We conclude that the use of localized basis sets provides a useful route forward for quantum mechanical studies of large-scale mineral problems.Received: 5 July 2001  相似文献   

An integrated thermodynamic mixing model for sphalerite geobarometry from 300 to 850°C and up to 1 GPa     

Jordi Delgado Martín  Albert Soler I Gil 《Geochimica et cosmochimica acta》2005,69(4):995-1006

An asymmetric, Margules-type, solid solution model was used to model the mixing behavior of Fe-Zn sphalerites. The model is based on an analysis of experimental results from fifteen independent data sources. After a careful, stepwise, analysis of the available runs, the solid solution model was constrained using a refined experimental database of 279 experiments which were simultaneously regressed to obtain the excess parameters and a general geobarometric equation. The model indicates that, when pressures are low, the value of γ_FeS^Sph, which is always greater than one, is higher at low FeS contents and an increase in temperature causes it to decline. However, for certain compositions γ_FeS^Sph values might be slightly less at low T than at high T. This behavior is corrected when pressure increases, regardless of the composition. The excess Gibbs free energy has positive values at any P&T while it is asymmetric. Pressure increases the value of the excess free energy. On the other hand, the Gibbs free energy of mixing is always negative, with a single minimum that tends to move towards Fe-poorer compositions as the pressure goes up. An increase in temperature leads to a more negative Gibbs free energy mixing function suggesting that increasingly Fe-poorer sphalerite would be expected at high temperatures and pressures. The application of the solid solution model to a selection of case-studies provided results which are consistent with independent pressure estimates. However, the pressure determinations for sphalerite + pyrite + pyrrhotite and sphalerite + pyrrhotite assemblages are very sensitive to uncertainties in the composition of the phases involved and, to a lesser extent, to temperature. The results of the application of the model to a field case (scheelite-mineralized Hercynian veins from the Central Pyrenees) were also consistent when compared with independent pressure-constraining silicate assemblages. Thus, the solid solution model described in this paper provides a workable framework with which to compute the pressures of the formation of rocks over a wide range of geological conditions.  相似文献   

On covariance propagation of eigenparameters of symmetric n-D tensors     

J. Y. Han  B. H. W. van Gelder  T. Soler 《Geophysical Journal International》2007,170(2):503-510

Symmetric tensors are typically encountered during investigations associated with stress and strain analysis and, thus, they are of particular interest to geophysicists and geodesists. Furthermore, symmetric tensors are studied using eigentheory analysis which provides the decomposition of the tensor on its principal components (n independent eigenvalues and the corresponding eigenvectors). In this paper, an analytical expression of the covariance matrix of the eigenvalues and eigenvectors of an n-D symmetric tensor is derived based on the principles of linear algebra and differential calculus. Through numerical tests, the proposed formulation is proven to give realistic uncertainty estimates of the determined eigenparameters. The methodology also reveals the significant impact on uncertainty assessments when the parameter dependencies between principal components are neglected.  相似文献