462 research outputs found
New lithostratigraphy for the Cantabrian Mountains: A common tectono-stratigraphic evolution for the onset of the Alpine cycle in the W Pyrenean realm, N Spain
The Pyrenean-Cantabrian Orogen arose through the collision of the Iberian and Eurasian plates, mostly in Cenozoic times. This orogen comprises two main mountain ranges, the Pyrenees to the east, and the Cantabrian Mountains to the west. To date, the early Alpine tectono-sedimentary phases preserved in the Cantabrian Mountains, of Permian and Triassic age, have been considered independently from the same phases in neighbouring basins of SW Europe, and even from the eastern part of the same orogeny (the Pyrenean orogeny). In consequence, the beginning of the Alpine cycle in the Cantabrian Mountains has been interpreted within a specific geodynamic context, far from the general evolutionary phases of the western Peri-Tethys basins. Through detailed field work, including geological mapping, sedimentology, lithostratigraphy and petrology of volcanic rocks, and new palaeontological data, here we define several new lithostratigraphical formations and five new tectono-sedimentary cycles (TS I-V) for the initial phases of evolution of the Mesozoic Basque-Cantabrian Basin, interrupted by periods of tectonic stability. To complete this information, we include data from an onshore borehole (Villabona Mine) and two offshore boreholes constrained by 2D reflection seismic profiles acquired in the North Iberian continental platform. The main tectono-sedimentary cycles, related to the deposition of five major identified lithostratigraphic units, can be described as follows: TS I (late Gzelian-early Asselian), relating to the late Variscan deformation and preserved in a single outcrop in all the Cantabrian Mountains (San Tirso Formation). This formation is constituted by medium-distal alluvial fan deposits in which humid intervals predominate, forming some thin coal beds. TS II (Asselian-Sakmarian), a post-Variscan extensional phase with associated calc-alkaline magmatism, represented by profuse volcanic and volcanosedimentary intercalations in the early Permian sedimentary basins (Acebal Formation) and small plutons in surrounding areas. TS III (Kungurian), or reactivation of the post-Variscan extension leading to alluvial and lacustrine carbonate sedimentation in arid climate conditions, which do not change during the rest of the Permian and Triassic periods (Sotres Formation). A generalized karstification in the basin represents the end of Permian deposition, followed by an interruption in sedimentation longer than 30 Myr. The Permian tectono-sedimentary cycles (TS II and TS III) are contemporary with Variscan belt collapse and the basins are controlled by extensional reactivation of NE-SW and E-W Variscan structures, and NW-SE late Variscan structures. TS IV (late Anisian–middle Carnian), renewed sedimentation in more extensive basins, precursors of the great Mesozoic Basque-Cantabrian Basin. This cycle is represented by fluvial deposits (Cicera Formation, or Buntsandstein facies), which are interrupted by the first Mesozoic marine ingression (Rueda Formation, or Muschelkalk facies). TS V (Norian-Rhaetian), or shallow marine carbonate deposits (Transición Formation) related to increasingly compartmentalized sub-basins, controlled by normal faults. This final TS is broadly connected with different basins of the western Peri-Tethys domain. The identification of units TS I-V in the Cantabrian Mountains along with the volcanic character of TS II, all indicate the development of a common post-Variscan to early Alpine tectono-sedimentary evolution for the whole Pyrenean-Cantabrian realm
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
We report a multi-resolution search for anisotropies in the arrival
directions of cosmic rays detected at the Pierre Auger Observatory with local
zenith angles up to and energies in excess of 4 EeV ( eV). This search is conducted by measuring the angular power spectrum
and performing a needlet wavelet analysis in two independent energy ranges.
Both analyses are complementary since the angular power spectrum achieves a
better performance in identifying large-scale patterns while the needlet
wavelet analysis, considering the parameters used in this work, presents a
higher efficiency in detecting smaller-scale anisotropies, potentially
providing directional information on any observed anisotropies. No deviation
from isotropy is observed on any angular scale in the energy range between 4
and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no
other deviation from isotropy is observed for moments beyond the dipole one.
The corresponding -values obtained after accounting for searches blindly
performed at several angular scales, are in the case of
the angular power spectrum, and in the case of the needlet
analysis. While these results are consistent with previous reports making use
of the same data set, they provide extensions of the previous works through the
thorough scans of the angular scales.Comment: Published version. Added journal reference and DOI. Added Report
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Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory
On September 14, 2015 the Advanced LIGO detectors observed their first
gravitational-wave (GW) transient GW150914. This was followed by a second GW
event observed on December 26, 2015. Both events were inferred to have arisen
from the merger of black holes in binary systems. Such a system may emit
neutrinos if there are magnetic fields and disk debris remaining from the
formation of the two black holes. With the surface detector array of the Pierre
Auger Observatory we can search for neutrinos with energy above 100 PeV from
point-like sources across the sky with equatorial declination from about -65
deg. to +60 deg., and in particular from a fraction of the 90% confidence-level
(CL) inferred positions in the sky of GW150914 and GW151226. A targeted search
for highly-inclined extensive air showers, produced either by interactions of
downward-going neutrinos of all flavors in the atmosphere or by the decays of
tau leptons originating from tau-neutrino interactions in the Earth's crust
(Earth-skimming neutrinos), yielded no candidates in the Auger data collected
within s around or 1 day after the coordinated universal time (UTC)
of GW150914 and GW151226, as well as in the same search periods relative to the
UTC time of the GW candidate event LVT151012. From the non-observation we
constrain the amount of energy radiated in ultrahigh-energy neutrinos from such
remarkable events.Comment: Published version. Added journal reference and DOI. Added Report
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Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter
An in-situ calibration of a logarithmic periodic dipole antenna with a
frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of
a radio station system used for detection of cosmic ray induced air showers at
the Engineering Radio Array of the Pierre Auger Observatory, the so-called
Auger Engineering Radio Array (AERA). The directional and frequency
characteristics of the broadband antenna are investigated using a remotely
piloted aircraft (RPA) carrying a small transmitting antenna. The antenna
sensitivity is described by the vector effective length relating the measured
voltage with the electric-field components perpendicular to the incoming signal
direction. The horizontal and meridional components are determined with an
overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} %
respectively. The measurement is used to correct a simulated response of the
frequency and directional response of the antenna. In addition, the influence
of the ground conductivity and permittivity on the antenna response is
simulated. Both have a negligible influence given the ground conditions
measured at the detector site. The overall uncertainties of the vector
effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in
the square root of the energy fluence for incoming signal directions with
zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is
unchanged with respect to v2. 39 pages, 15 figures, 2 table
Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory
The azimuthal asymmetry in the risetime of signals in Auger surface detector
stations is a source of information on shower development. The azimuthal
asymmetry is due to a combination of the longitudinal evolution of the shower
and geometrical effects related to the angles of incidence of the particles
into the detectors. The magnitude of the effect depends upon the zenith angle
and state of development of the shower and thus provides a novel observable,
, sensitive to the mass composition of cosmic rays
above eV. By comparing measurements with predictions from
shower simulations, we find for both of our adopted models of hadronic physics
(QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass
increases slowly with energy, as has been inferred from other studies. However,
the mass estimates are dependent on the shower model and on the range of
distance from the shower core selected. Thus the method has uncovered further
deficiencies in our understanding of shower modelling that must be resolved
before the mass composition can be inferred from .Comment: Replaced with published version. Added journal reference and DO
Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum
We report a first measurement for ultra-high energy cosmic rays of the
correlation between the depth of shower maximum and the signal in the water
Cherenkov stations of air-showers registered simultaneously by the fluorescence
and the surface detectors of the Pierre Auger Observatory. Such a correlation
measurement is a unique feature of a hybrid air-shower observatory with
sensitivity to both the electromagnetic and muonic components. It allows an
accurate determination of the spread of primary masses in the cosmic-ray flux.
Up till now, constraints on the spread of primary masses have been dominated by
systematic uncertainties. The present correlation measurement is not affected
by systematics in the measurement of the depth of shower maximum or the signal
in the water Cherenkov stations. The analysis relies on general characteristics
of air showers and is thus robust also with respect to uncertainties in
hadronic event generators. The observed correlation in the energy range around
the `ankle' at differs significantly from
expectations for pure primary cosmic-ray compositions. A light composition made
up of proton and helium only is equally inconsistent with observations. The
data are explained well by a mixed composition including nuclei with mass . Scenarios such as the proton dip model, with almost pure compositions, are
thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray
flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report
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RBX: The new X-band SAR system from INTA
Revista oficial de la Asociación Española de Teledetección[EN] This paper describes the characteristics and the first results of the RBX system, the new airborne Synthetic Aperture Radar developed at Spanish National Institute of Aerospace Technology. The new system supports submetric resolution with interferometric and polarimetric capabilities. The system architecture has been designed taking into account an easy upgrade ability and the quality of the acquired data, including multiple internal calibration loops.[ES] Este artículo describe las características y los primeros resultados del sistema RBX, nuevo radar de apertura sintética aerotransportado que ha sido desarrollado en el Instituto Nacional de Técnica Aeroespacial. El nuevo sistema soporta resoluciones submétricas con capacidades interferométricas y polarimétricas. La arquitectura del sistema se ha diseñado teniendo en cuenta la facilidad de incorporar mejoras y la calidad de los datos adquiridos, incluyendo múltiples lazos de calibración interna.Larrañaga, J. R., De Porras Bernácer, R., Del Castillo, J., Gimeno, N., Aguilar, P., Baquero, A. M., . . . Sánchez, S. (2014). RBX: The new X-band SAR system from INTA. [RBX: El nuevo radar SAR en banda X del INTA] Revista De Teledeteccion, (41), 89-96. doi:10.4995/raet.2014.2285SWORD899641G. Bonin, P. Dreuillet. 2008. The new ONERA airborne SAR system SETHI. EUSAR, Dresden, Germany.Rodriguez, M. G. (2008). Design of a Coherent Generation and Acquisition System at 1,2GHz. 2008 4th Southern Conference on Programmable Logic. doi:10.1109/spl.2008.4547745Gonzalez Bonilla, M. J., Gomez Miguel, B., Cuerda Muñoz, J. M., Larrañaga Sudupe, J. R., Garcia Rodriguez, M., 2009. INTASAR program. Proceedings IGARSSHORN, RALF; NOTTENSTEINER, ANTON; SCHEIBER, ROLF. 2008. F-SAR – DLR's advanced airborne SAR system onboard DO228. Proceedings EUSARMoreira, A., & Yonghong Huang. (1994). Airborne SAR processing of highly squinted data using a chirp scaling approach with integrated motion compensation. IEEE Transactions on Geoscience and Remote Sensing, 32(5), 1029-1040. doi:10.1109/36.31289
Guía de Incorporación de Cartas Temáticas Pre-existentes de la Dirección de Geología Ambiental y Aplicada de la República de Argentina a Escala 1:250.000
Fil: Pedreira Junco, José Ángel. SADIM: Sociedad Asturiana de Diversificación Minera; España.
.Fil: Avanzas, Rubén. SADIM: Sociedad Asturiana de Diversificación Minera; España.Fil: López Rivas, J. SADIM: Sociedad Asturiana de Diversificación Minera; España.Fil: Tobio, María Inés. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Chavez, Roxana. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: González, María Alejandra. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Elisondo, Manuela. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Villegas, Daniela. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Caballaro, Sandra. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Nicosia Burgos, Federico R. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Rivas, Irma S. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Fratalochi, Catalina. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Tello, Norma Elisa. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Ferpozzi, Federico Javier. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Candaosa, Norberto Gabriel. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Chavez, Silvia Beatríz. SEGEMAR: Servicio Geológico Minero Argentino; Argentina.Fil: Álvarez Fernández, Saúl. SADIM: Sociedad Asturiana de Diversificación Minera; España
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