Diachronism in the late Neoproterozoic–Cambrian arc-rift transition of North Gondwana: a comparison of Morocco and the Iberian Ossa-Morena Zone

In the northwestern border of the West African craton (North Gondwana), a transition from late Neoproterozoic subduction/collision to Cambrian rift processes was recorded in the Anti-Atlas (Morocco) and in the Ossa-Morena Zone (Iberia). Cambrian rifting affected both Pan-African and Cadomian basements in a stepwise and diachronous way. Subsequently, both areas evolved into a syn-rift margin episodically punctuated by uplift and tilting that precluded Furongian sedimentation. A comparison of sedimentary, volcanic and geodynamic evolution is made in the late Neoproterozoic (Pan-African and Cadomian) belts and Cambrian rifts trying to solve the apparent diachronous (SW–NE-trending) propagation of an early Palaeozoic rifting regime that finally led to the opening of the Rheic Ocean

Tracing the Cadomian magmatism with detrital/inherited zircon ages by in-situ U–Pb SHRIMP geochronology (Ossa-Morena Zone, SW Iberian Massif),

U–Pb SHRIMP geochronology on zircon extracted from a granite, a sandstone and a quartzite of the SW Iberian Massif (Ossa-Morena Zone), was used in order to investigate the contribution of Late Neoproterozoic (Cadomian) tectonothermal history to the crustal growth of northern Gondwana. The analysed Cambrian rocks were sampled along the southern margin of the Coimbra–Cordoba shear zone (Barquete granite and Crato sandstone), and within this shear zone (Ouguela quartzite). The Barquete granite yielded a crystallization age of 526±4 Ma and evidence for Neoproterozoic and Paleoproterozoic inherited ages. The geochemical signature of the Barquete granite matches the igneous activity of the initial magmatic flooding of the Ossa-Morena Zone during the Early Cambrian. The petrography and geochemical signature of the Crato and Ouguela sandstones indicate that these clastic rocks were mainly derived from felsic igneous rocks. The youngest detrital zircon grain extracted from the Crato sandstone, dated at 552.7±5.5 Ma, has a zircon overgrowth that yielded 532±5.6 Ma. In the Ouguela quartzite, the youngest concordant age yielded 556.4±5.7 Ma, but we also found a zircon overgrowth dated at 536.2±5.6 Ma. The ages of the youngest detrital zircon in each sedimentary rock place an upper limit on the deposition age of Early Cambrian (c. 536– 532 Ma). Four main Late Neoproterozoic age clusters at c. 640–638 Ma, c. 612–613 Ma, c. 590–585 Ma and c. 560 Ma were recognized in the populations of detrital zircons from both sandstones. These ages of zirconforming events seem to represent four successive thermal/magmatic pulses that overlap the Cadomian and Pan-African orogenies. These findings match other results published for the OMZ. Our U–Pb results show that detrital zircons in siliciclastic sediments and inherited zircon in granites are dominated by Neoproterozoic ages and few Paleoproterozoic and Archean ages. Those ages reported in the Ossa-Morena Zone rocks, together with a remarkable lack of Mesoproterozoic ages suggest that the clastic rocks in this peri-Gondwana basin were derived from the West African craton. The large population of Late Cryogenian and Ediacaran ages indicates denudation of the Cadomian basement during the Early Cambrian. A potential source for the detrital and inherited zircons found in this study is a long-lived magmatic arc that is only partly exposed in the SW Iberian Massif but is well represented in other peri-Gondwana regions. The large amount of Cadomian ages obtained in this study (c. 640–560 Ma) reinforces the idea that Cadomian magmatism played a significant role in the continental crustal growth history of Late Neoproterozoic uplift and erosion in Western and Central Europe (Cadomia)

Rift-related volcanism predating the birth of the Rheic Ocean

Two very different periods of magma emplacement in the crust of the Ossa-Morena zone (early and main events) in SW Iberia have been previously interpreted to record a Cambrian/Early Ordovician rifting event that is thought to have culminated in the opening of the Rheic Ocean during the Early Ordovician. New stratigraphic, petrographic, geochemical and Sm–Nd isotope data from Cambrian volcanic rocks included in six key low-grade sections in both Portugal and Spain considerably improve our understanding of these events. These data: (1) confirm the existence of two rift-related magmatic events in the Cambrian of the Ossa-Morena zone, (2) demonstrate that the early rift-related event was associated with migmatite and core-complex formation in the mid-upper crust and is represented by felsic peraluminous rocks, the parent magmas of which were derived mainly from crustal sources, and (3) show the main rift-related event to be represented by a bimodal association of felsic and mafic rocks with minor amounts of intermediate rocks. Some of the mafic rocks show N-MORB affinity, whereas others have OIB or E-MORB affinities, suggesting different heterogeneous mantle sources (depleted and enriched, asthenospheric and lithospheric, plume-like and non-plume-like). The acid and intermediate rocks appear to represent hybrid mixtures of crust and mantle-derived magmas. This new data supports the hypothesis that the onset of rifting was associated with a process of oblique ridgetrench collision. We interpret the significant differences between the early and main events as reflecting the evolution froma wide rift stagewith passive extensionmainly accommodated by lower-crust flowin a high heatflow setting, to a narrow rift stage with active extension characterized by extension rates that outpaced thermal diffusion rates

La importancia de la ética pública frente a la corrupción en la administración de justicia, Arequipa, 2022

La presente investigación lleva como título: “La importancia de la ética pública frente a la corrupción en la administración de justicia, Arequipa, 2022” la cual tuvo como objetivo general; Determinar la importancia de la ética pública frente a la corrupción en la administración de justicia Arequipa, 2022. Así mismo se trabajó con dos categorías de estudio las cuales fueron: Ética pública y Corrupción en la administración de justicia En el desarrollo de la investigación se utilizó el enfoque cualitativo, respecto al tipo de investigación se aplicó la investigación básica con un diseño Jurídico-Propositivo. Respecto a las técnicas e instrumentos para el análisis de las categorías de investigación planteadas fue necesario el uso de cuestionarios, entrevistas y análisis documental. Concluyendo que se determinó el compromiso de la ética en el ámbito público cobra importancia debido a que sirve como estrategia para sus respectivas administraciones, como medida para combatir las prácticas corrupta

Bioinspired catechol-terminated self-assembled monolayers with enhanced adhesion properties

The role of the catechol moiety in the adhesive properties of mussel proteins and related synthetic materials has been extensively studied in the last years but still remains elusive. Here, a simplified model approach is presented based on a self-assembled monolayer (SAM) of upward-facing catechols thiol-bound to epitaxial gold substrates. The orientation of the catechol moieties is confirmed by spectroscopy, which also showed lack of significant amounts of interfering o-quinones. Local force-distance curves on the SAM measured by atomic force microscopy (AFM) shows an average adhesion force of 45 nN, stronger than that of a reference polydopamine coating, along with higher reproducibility and less statistical dispersion. This is attributed to the superior chemical and topographical homogeneity of the SAM coating. Catechol-terminated SAMs are also obtained on high-roughness gold substrates that show the ability to assemble magnetic nanoparticles, despite their lack of enhanced adhesion at the molecular level. Finally, the influence of the catechol group on the formation and quality of the SAM is explored both theoretically (molecular dynamics simulations) and experimentally using direct-write AFM lithography.Peer ReviewedPostprint (published version

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file