High-pressure greenschist to blueschist facies transition in the Maimón Formation (Dominican Republic) suggests mid-Cretaceous subduction of the Early Cretaceous Caribbean Arc

The Maimón Formation (Cordillera Central, Dominican Republic) is formed of metamorphosed bi-modal mafic-felsic volcanic rocks and sedimentary horizons of Early Cretaceous age deposited in the forearc of the nascent Caribbean island arc. Two structural-metamorphic zones depict an inverted metamorphic gradient: the Ozama shear zone, which records intense mylonitic and phyllonitic deformation and ubiquitous metamorphic recrystallization, tectonically overlies the much less deformed and variably recrystallized rocks of the El Altar zone. The presence of ferri-winchite and high-Si phengite, first reported in this paper, in the peak metamorphic assemblage of rocks of the Ozama shear zone (actinolite + phengite + chlorite + epidote + quartz + albite ± ferri-winchite ± stilpnomelane) point to subduction-related metamorphism. Pseudosection calculations and intersection of isopleths indicate peak metamorphic conditions of ~ 8.2 kbar at 380 °C. These figures are consistent with metamorphism in the greenschist/blueschist facies transition, burial depths of ~ 25-29 km and a thermal gradient of ~ 13-16 °C/km. Our new data dispute previous models pointing to metamorphism of Maimón rocks under a steep thermal gradient related to burial under a hot peridotite slice. Instead, we contextualize the metamorphism of the Maimón Formation in a subduction scenario in which a coherent slice of the (warm) Early Cretaceous forearc was engulfed due to intra-arc complexities and regional-scale-driven tectonic processes operating in the late Early Cretaceous. Integration of our findings with previous studies on metamorphic complexes in Hispaniola suggests that a major tectonic event affecting the whole arc system took place at c. 120-110 Ma

Las formulaciones emulsionables de Dimetildisulfuro (DMDS) y sus mezclas con cloropicrina como alternativas al bromuro de metilo

Desde hace mucho tiempo se sabe que plantas de los géneros Allium sp. y Brassica sp. poseen una cierta capacidad antimicrobiana. Este poder ha sido explicado por la presencia de radicales sulfuro de alilo y sulfuro de metilo derivados de sulfóxido de LCisteina existente en los ajos y las brasicas. Una de las sustancias más interesantes es el Disulfuro de dimetilo (DMDS) que es un importante compuesto de los Allium sp., especialmente del ajo. Aunque sus propiedades fumigantes se conocen desde hace poco tiempo, el DMDS se viene utilizando desde hace mucho en la industria petroquímica e incluso como agente de aromas por su fuerte olor a ajo. El DMDS es un fumigante de amplio espectro con efectos nematicida, fungicida insecticida y herbicida, que ejerce su acción a nivel de respiración mitocondrial bloqueando la actividad citocromo oxidasa de las células. Los efectos nematicidas se han podido comprobar contra Heterodera sp. y Meloidogyne sp., mediante aplicación en preplantación. Se le reconoce eficacia contra hongos del suelo como Sclerotium rolfsii, Rhizoctonia solani, Phytophthora cactorum pero no tan efectivo contra Macrophomina phaseolina y solo parcialmente contra Sclerotinia scleritiorum. Desde el año 2003 al 2007 hemos venido estudiando sus efectos como alternativa al bromuro de metilo en el cultivo de pimiento en las zonas del Bajo Segura (SURINVER, Pilar de la Horadada, Alicante) y en La Canal de Navarrès (VALSUR, SAT Bolbaite, Valencia) usando formulaciones emulsionables aplicadas con el riego localizado, tanto sólo como mezclado con diversas proporciones de cloropicrina (50%; 33%), con objeto de mejorar su eficacia fungicida. El DMDS sólo, a dosis elevadas (105 g/m2), tiene una capacidad herbicida notable; a menor dosis, sus mezclas con cloropicrina poseen un excelente efecto fumigante que mejora cuando se aplica bajo plástico VIF. El efecto fungicida también mejora ostensiblemente. Una vez depurada la técnica de aplicación la calidad y producción de pimiento es comparable a la obtenida con los tratamientos tradicionales con bromuro de metilo

Re-Os and U-Pb Geochronology of the Doña Amanda and Cerro Kiosko Deposits, Bayaguana District, Dominican Republic: Looking Down for the Porphyry Cu-Mo Roots of the Pueblo Viejo-Type Mineralization in the Island-Arc Tholeiitic Series of the Caribbean

Hosted in the Early Cretaceous bimodal tholeiite volcanic series of the Los Ranchos Formation, the Doña Amanda and Cerro Kiosko deposits in the Bayaguana district represent significant Au, Cu, and Ag resources in the Cordillera Oriental of the Dominican Republic. At Doña Amanda, a dense stockwork of quartz-sulfide veins is hosted by volcanic rocks with intense transitional phyllic-advanced argillic and silicic hydrothermal alteration assemblages, indicating a high-sulfidation environment. Wavy quartz veins with central sutures and rims of pyrite + enargite + molybdenite + fahlore (B veins) are cut by planar quartz-pyrite D veins. Primary fluid inclusions in quartz from B veins (Th: 160°->400°C; salinity: 7.9-16.4 wt % NaCl equiv) are interpreted as porphyry-type fluids. Inclusion fluids in quartz of quartz-pyrite veins (Th: 125°-175°C; salinity: 4.8-12.2 wt % NaCl equiv), quartz from silicic altered wall rocks (Th: 150°-175°C; salinity: 8.3-13.9 wt % NaCl equiv), and late, distal calcite veins (Th: 120°-160°C; salinity: 5.0-13.3 wt % NaCl equiv) indicate limited mixing with more dilute fluids and rule out mixing with fresh meteoric water. In Cerro Kiosko, a swarm of fault-controlled massive chalcopyrite + enargite + bornite + fahlore D veins and lodes are hosted by rocks with pervasive kaolinite alteration after sericite. δ34S values of vein sulfides from both deposits are all close to −2¿ and consistent with a predominance of magmatic sulfur and sulfide deposition from an oxidizing magmatic fluid. These data are consistent with a transitional environment between a deeper porphyry Cu(-Mo) and an overlying high-sulfidation epithermal deposit. An Re-Os age (112.6 ± 0.4 Ma) for molybdenite from the Doña Amanda deposit places the porphyry-epithermal mineralization as Early Cretaceous, coeval with the Los Ranchos Formation host rocks and with the Pueblo Viejo deposit. New sensitive high-resolution ion microprobe U-Pb ages on zircons from plagioclase-phyric rhyolite domes in the Bayaguana district are consistent with porphyry-high-sulfidation epithermal mineralization occurring along the Los Ranchos Formation during tonalite batholith emplacement in the basaltic island-arc basement at ca. 118 to 112 Ma and finalization of felsic volcanism at ca. 110 to 107 Ma

Modalidades productivas en el pimiento de invernadero y su incidencia en la comercialización

Se comenta, en principio, la situación económica del pimiento y cual es su posición competitiva. Actualmente la producción y comercialización de pimiento se encuentran muy condicionadas en aspectos económicos, medioambientales, y de la calidad y seguridad alimentaria, que se pueden sintetizar en: Unos costes de producción elevados; los mercados se encuentran muy abastecidos, con riesgo de saturación y descenso de los precios; dominio de la gran distribución en la comercialización; Política Agraria Comunitaria (PAC) a favor del medioambiente y de la biodiversidad; sensibilización de los consumidores por la sanidad de los productos y obligación de cumplir con la trazabilidad. Aunque España ha competido favorablemente con otros países europeos, en las producciones hortofrutícolas de invernadero, deberá en el futuro tener en cuenta a los países mediterráneos, más aún, después del Acuerdo Euromediterráneo. En el trabajo se analizan las características de la producción de pimiento en invernadero, centradas en el cultivo en sustrato, la producción integrada y la producción ecológica. Una vez efectuada la valoración económica de cada modalidad productiva, se establecen una serie de consideraciones sobre la incidencia de cada una de ellas en la comercialización

Petrogenesis of volcanic rocks from the Maimón Formation (Dominican Republic): Geochemical record of the nascent Greater Antilles paleo-arc

Metamorphosed basalts, basaltic andesites, andesites and plagiorhyolites of the Early Cretaceous, probably pre-Albian, Maimón Formation, located in the Cordillera Central of the Dominican Republic, are some of the earliest products of the Greater Antilles arc magmatism. In this article, new whole-rock element and Nd-Pb radiogenic isotope data are used to give new insights into the petrogenesis of the Maimón meta-volcanic rocks and constrain the early evolution of the Greater Antilles paleo-arc system. Three different groups of mafic volcanic rocks are recognized on the basis of their immobile element contents. Group 1 comprises basalts with compositions similar to low-Ti island arc tholeiites (IAT), which are depleted in light rare earth elements (LREE) and resemble the forearc basalts (FAB) and transitional FAB-boninitic basalts of the Izu-Bonin-Mariana forearc. Group 2 rocks have boninite-like compositions relatively rich in Cr and poor in TiO2. Group 3 comprises low-Ti island arc tholeiitic basalts with near-flat chondrite-normalized REE patterns. Plagiorhyolites and rare andesites present near-flat to subtly LREE-depleted chondrite normalized patterns typical of tholeiitic affinity. Nd and Pb isotopic ratios of plagiorhyolites, which are similar to those of Groups 1 and 3 basalts, support that these felsic lavas formed by anatexis of the arc lower crust. Geochemical modelling points that the parental basic magmas of the Maimón meta-volcanic rocks formed by hydrous melting of a heterogeneous spinel-facies mantle source, similar to depleted MORB mantle (DMM) or depleted DMM (D-DMM), fluxed by fluids from subducted oceanic crust and Atlantic Cretaceous pelagic sediments. Variations of subduction-sensitive element concentrations and ratios from Group 1 to the younger rocks of Groups 2 and 3 generally match the geochemical progression from FAB-like to boninite and IAT lavas described in subduction-initiation ophiolites. Group 1 basalts likely formed at magmatic stages transitional between FAB and first-island arc magmatism, whereas Group 2 boninitic lavas resulted from focused flux melting and higher degrees of melt extraction in a more mature stage of subduction. Group 3 basalts probably represent magmatism taking place immediately before the establishment of a steady-state subduction regime. The relatively high extents of flux melting and slab input recorded in the Maimón lavas support a scenario of hot subduction beneath the nascent Greater Antilles paleo-arc. Paleotectonic reconstructions and the markedly depleted, though heterogeneous character of the mantle source, indicate the rise of shallow asthenosphere which had sourced mid-ocean ridge basalts (MORB) and/or back-arc basin basalts (BABB) in the proto-Caribbean domain prior to the inception of SW-dipping subduction. Relative to the neighbouring Aptian-Albian Los Ranchos Formation, we suggest that Maimón volcanic rocks extruded more proximal to the vertical projection of the subducting proto-Caribbean spreading ridge

Mineralogy, geochemistry and sulfur isotope characterization of Cerro de Maimón (Dominican Republic), San Fernando and Antonio (Cuba) lower Cretaceous VMS deposits: Formation during subduction initiation of the proto-Caribbean lithosphere within a fore-arc

The volcanic-arc Lower Cretaceous Maimón (Dominican Republic) and Los Pasos (Cuba) Formations, representative of the oldest magmatism recorded in the Caribbean island arc, host most of the known volcanogenic massive sulfide (VMS) deposits in the Greater Antilles. On the basis of new lithogeochemical data, basalts of the Maimón Formation are classified as fore arc basalts (FAB), boninites and less abundant low-Ti (LOTI) and normal island-arc tholeiites (IAT), and those of the Los Pasos Formation as LOTI and IAT. Felsic volcanics from the two formations are geochemically analogous and present mantle-type (M-type), boninitic and tholeiitic signatures, classifying as FIV-type, typical of post-Archaean VMS-bearing juvenile volcanic suites. This lithogeochemical data is indicative of formation in a fore-arc environment just after subduction initiation in association with initial extensional regimes and associated boninitic and tholeiitic melts that originated in the shallow mantle. Within this tectonic framework, rocks of the Los Pasos Formation and associated VMS deposits likely formed at a slightly later stage than those of the Maimón Formatio

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations