No direct contribution of recycled crust in Icelandic basalts

Using Melt-PX to model the decompression melting of a heterogeneous mantle, I investigated the role of major-element composition of the lithologies present in the source on magmatic productivity, and trace element and isotopic melt compositions, independently of the bulk mantle composition. My calculations demonstrate that the volume of magma produced is not significantly affected by the nature of the lithological heterogeneity, but depends on the bulk mantle composition. However, an isochemical bulk mantle can produce contrasting trace element and isotopic melt compositions depending on the major-element compositions of the lithologies present in the source. Results show that the observed crust thickness of the Icelandic rift zones is consistent with about 10 % of recycled crust in the source, but also demonstrate there is no need to involve the contribution of melts derived from a recycled basalt component to explain the compositional variability of the Icelandic basalts in rift zones, and rather advance the contribution of olivine-bearing hybrid lithologies formed by solid-state reactions between the recycled crust and the peridotite

La Triada Oscura de la Personalidad y tácticas de retención de pareja

Una versión preliminar de este trabajo fue presentada como Trabajo Fin de Grado en Psicología en la Universidad de Huelva, siendo dirigido por la segunda autora y defendido por la primera autora.El objetivo principal de este estudio ha sido analizar la «Triada Oscura de la Personalidad» y las tácticas de retención de pareja en una muestra de población general. Asimismo, como objetivos específicos se plantea determinar la incidencia de los rasgos de la Triada en dicha muestra, así como estudiar la existencia de diferencias en las tácticas de retención de pareja utilizadas en función del sexo, situación sentimental y orientación sexual de los participantes.Se ha realizado un diseño transversal y se siguió una metodología selectiva ex post facto. La muestra estuvo compuesta por 229 personas de edades comprendidas entre 17 y 62 años y fue seleccionada mediante un muestreo accidental online. Para la recogida de datos se aplicaron tres cuestionarios; The Dirty Dozen (DD), Mate Retention Inventory-Short Form (MRI-SF) y Protocolo de recogida de información sociodemográfica. Los resultados obtenidos muestran que los hombres presentan mayor TRIOPE que las mujeres, que éstos aplican mayores tácticas de retención de pareja, y que las personas que conviven con su pareja utilizan más tácticas de retención de pareja.The main objective of this study has been analyzed in the Dark Triad Personality and the retention tactics of couple in a sample of general population. Likewise, specific objectives are to determine the incidence of Triada traits in the sample, as well as to study the existence of differences in the retention tactics of couples based on sex, the emotional situation and the sexual orientation of the participants. A cross-sectional design was carried out and an ex post facto selective methodology was followed. The sample consisted of 229 people aged between 17 and 62 years and was selected by means of an accidental online sampling. For data collection, three questionnaires were applied; The Dirty Dozen (DD), Mate Retention Inventory Short-Form (MRI-SF) and Protocol for the Collection of Sociodemographic Information. The results obtained show that men present a greater TRIOPE than women, these apply greater retention tactics of couple, and that the people who live with their partner they use more retention tactics of couple

Corrigendum to “Testing pyroxenite versus peridotite sources for marine basalts using U-series isotopes” [Lithos 332–333 (2019) 226–244]

The authors regret that a small error in the dynamic melting Matlab script used for this paper produced erroneous results for some of the included modeling outcomes. We have written an updated modeling program in python, which can be accessed in the ENKI and pyUserCalc public data repository (https://gitlab.com/ENKI-portal/pyUsercalc/). Although the corrected results shown in revised versions of Figs. S3, S4, S8, S9, and S10 now appear quite different from the original publication, however, we find that when restricted to plausible scenarios of interest, our conclusions overall have not significantly changed. Some details of our results and discussion require corrections, however

Testing pyroxenite versus peridotite sources for marine basalts using U-series isotopes

Geochemically enriched signatures in global oceanic basalts have long indicated a heterogeneous mantle source, but the role of lithologic heterogeneity in producing mantle partial melts, particularly fertile pyroxenite rocks, remains unclear. Uranium-series disequilibria in basalts are particularly sensitive to the increased garnet mode and melting rates of pyroxenite rocks, making the system a useful indicator of mantle lithologic heterogeneity in the melt region for oceanic basalts. Here we summarize evidence for the presence and importance of pyroxenite rocks in the upper mantle and their role in melt generation of mid-ocean ridge basalts and ocean island basalts, with a synthesis of U-series disequilibrium systematics in oceanic basalts and implications for global lithologic heterogeneity of the upper mantle. We further synthesize the melt modeling approaches for the interpretation of U-series disequilibria in basalts and demonstrate the use of numerical solution models for time-dependent reactive porous flow and dynamic melting during decompression of a two-lithology mantle in thermal equilibrium. Our model outcomes corroborate prior interpretations in favor of reactive porous flow and two-porosity transport for relatively homogeneous, peridotite-dominated mantle regimes, and further support contributions of pyroxenite partial melts to aggregated melts in order to reproduce the heterogeneous global basalt data. To most accurately predict the conditions of melting by comparison with measured data, two-lithology melting calculations should carefully consider the role of thermal equilibrium, mineral/melt partitioning, non-linear variations in mineral modes, and degree of melting during the melting process

Uranium-series disequilibria in MORB, revisited: A systematic numerical approach to partial melting of a heterogeneous mantle

We present computational modeling outcomes for bilithologic (peridotite and pyroxenite) mantle melting in divergent environments, considering equilibrium and disequilibrium porous flow melting of 0–50 % pyroxenite in thermal equilibrium with peridotite, potential temperatures of 1300 and 1400 °C, upwelling rates from 1–50 cm yr−1, maximum porosities of 0.1–2.0 %, and four compositions that span pyroxenite melting behavior. Basalt-like pyroxenites (G2) uniquely produce low (226Ra/230Th) and (231Pa/235U) with high (230Th/238U), but quantities greater than ~10 % produce anomalously thick crust, restricting their global abundance. Silica-deficient pyroxenite (M7-16 and MIX1G) melts are more moderate, but require chemical re-equilibration during transport to resemble global basalts, while hybrid lithologies (KG1) produce melts similar to those of peridotites. Uranium-series disequilibria in partial melts can also be decoupled from trace elements by radioactive decay in two-dimensional regimes. The mantle must thus contain multiple types of pyroxenite on a global scale, with melts traveling by complex networks and experiencing heterogeneous extents of chemical re-equilibration

Reactive Infiltration of MORB-Eclogite-Derived Carbonated Silicate Melt into Fertile Peridotite at 3GPa and Genesis of Alkalic Magmas

We performed experiments between two different carbonated eclogite-derived melts and lherzolite at 1375°C and 3 GPa by varying the reacting melt fraction from 8 to 50 wt %. The two starting melt compositions were (1) alkalic basalt with 11·7 wt % dissolved CO2 (ABC), (2) basaltic andesite with 2·6 wt % dissolved CO2 (BAC). The starting melts were mixed homogeneously with peridotite to simulate porous reactive infiltration of melt in the Earth’s mantle. All the experiments produced an assemblage of melt + orthopyroxene + clinopyroxene + garnet ± olivine; olivine was absent for a reacting melt fraction of 50 wt % for ABC and 40 wt % for BAC. Basanitic ABC evolved to melilitites (on a CO2-free basis, SiO2 ∼27–39 wt %, TiO2 ∼2·8–6·3 wt %, Al2O3 ∼4·1–9·1 wt %, FeO* ∼11–16 wt %, MgO ∼17–21 wt %, CaO ∼13–21 wt %, Na2O ∼4–7 wt %, CO2 ∼10–25 wt %) upon melt–rock reaction and the degree of alkalinity of the reacted melts is positively correlated with melt–rock ratio. On the other hand, reacted melts derived from BAC (on a CO2-free basis SiO2 ∼42–53 wt %, TiO2 ∼6·4–8·7 wt %, Al2O3 ∼10·5–12·3 wt %, FeO* ∼6·5–10·5 wt %, MgO ∼7·9–15·4 wt %, CaO ∼7·3–10·3 wt %, Na2O ∼3·4–4 wt %, CO2 ∼6·2–11·7 wt %) increase in alkalinity with decreasing melt–rock ratio. We demonstrate that owing to the presence of only 0·65 wt % of CO2 in the bulk melt–rock mixture (corresponding to 25 wt % BAC + lherzolite mixture), nephelinitic-basanite melts can be generated by partial reactive crystallization of basaltic andesite as opposed to basanites produced in volatile-free conditions. Post 20% olivine fractionation, the reacted melts derived from ABC at low to intermediate melt–rock ratios match with 20–40% of the population of natural nephelinites and melilitites in terms of SiO2 and CaO/Al2O3, 60–80% in terms of TiO2, Al2O3 and FeO, and <20% in terms of CaO and Na2O. The reacted melts from BAC, at intermediate melt–rock ratios, are excellent matches for some of the Mg-rich (MgO >15 wt %) natural nephelinites in terms of SiO2, Al2O3, FeO*, CaO, Na2O and CaO/Al2O3. Not only can these reacted melts erupt by themselves, they can also act as metasomatizing agents in the Earth’s mantle. Our study suggests that a combination of subducted, silica-saturated crust–peridotite interaction and the presence of CO2 in the mantle source region are sufficient to produce a large range of primitive alkalic basalts. Also, mantle potential temperatures of 1330–1350°C appear sufficient to produce high-MgO, primitive basanite–nephelinite if carbonated eclogite melt and peridotite interaction is taken into account

The role of pyroxenite in basalt genesis: Melt-PX, a melting parameterization for mantle pyroxenites between 0.9 and 5 GPa

Geochemical and isotopic data suggest that the source regions of oceanic basalts may contain pyroxenite in addition to peridotite. In order to incorporate the wide range of compositions and melting behaviors of pyroxenites into mantle melting models, we have developed a new parameterization, Melt-PX, which predicts near-solidus temperatures and extents of melting as a function of temperature and pressure for mantle pyroxenites. We used 183 high-pressure experiments (25 compositions; 0.9–5 GPa; 1150–1675°C) to constrain a model of melt fraction versus temperature from 5% melting up to the disappearance of clinopyroxene for pyroxenites as a function of pressure, temperature, and bulk composition. When applied to the global set of experimental data, our model reproduces the experimental F values with a standard error of estimate of 13% absolute; temperatures at which the pyroxenite is 5% molten are reproduced with a standard error of estimate of 30°C over a temperature range of ~500°C and a pressure range of ~4 GPa. In conjunction with parameterizations of peridotite melting, Melt-PX can be used to model the partial melting of multilithologic mantle sources—including the effects of varying the composition and the modal proportion of pyroxenite in such source regions. Examples of such applications include calculations of isentropic decompression melting of a mixed peridotite + pyroxenite mantle; these show that although the potential temperature of the upwelling mantle plays an important role in defining the extent of magma production, the composition and mass fraction of the pyroxenite also exert strong controls

Apolipoprotein E4 facilitates transfection of human monocyte-derived dendritic cells by lipid nanoparticles

The use of mRNA as a therapeutic drug class is a safe and fast alternative to viral vector or plasmid DNA therapies. Nevertheless, free mRNA will be rapidly degraded after administration to the body and only reach the cytosol of desired cells with difficulty. Lipid nanoparticles (LNP) safely deliver mRNA to cells of interest and can be used in the treatment of different diseases. Dendritic cells are the primary antigen-presenting cells and important for mRNA vaccine delivery. Efforts to increase LNP transfection of these cells are necessary and can be achieved by different approaches. Here, we present apolipoprotein E4 addition to LNP administration as one mean of increasing LNP-mediated eGFP mRNA delivery to human monocyte-derived dendritic cells. We also show some steps in the preparation method for LNP optimization using MS2 RNA as a novel model nucleic acid

Tracing mantle source variation through xenocrystic olivine in the Taupo Volcanic Zone, New Zealand: A role for lithospheric mantle in the shift from andesitic to rhyolitic compositions

The central Taupo Volcanic Zone (TVZ) in New Zealand, the most productive of silicic volcanic centres, is flanked by younger andesitic stratovolcanoes to the south. Small basaltic scoria cones occur along the length of the TVZ, the most primitive of which contain abundant xenocrysts, giving insight into the mantle feeding the TVZ.Here, we present major and minor element compositions of olivine from eleven mafic eruptions spanning the length of the central and south TVZ. Olivine compositions can be divided into three major groups, based on their texture, major and minor element composition, and zoning. Group 1 olivines are Fo88 in the most primitive cores, with minor element concentrations consistent with magmatic origin. Group 2 olivine compositions range from Fo72–88 but are homogeneous within individual crystals. CaO contents are consistently lower for a given forsterite content compared to group 1 olivines and are most consistent with a plutonic crystal mush origin. Group 3 olivines have core compositions of Fo93–90, and NiO and CaO (0.36–0.56 wt%, &lt;0.15 wt%, respectively) concentrations consistent with a primary magma or mantle-derived origin. Compositional variation within group 3 olivine allows for further characterisation of the mantle lithologies from which the crystals were sourced. Group 3 olivines from the central TVZ are lherzolite-derived, whereas group 3 olivines from the south TVZ are harzburgite-derived. However, recent whole-rock and melt inclusion data suggests that the most fertile mantle underlies the south TVZ, and the least fertile mantle underlies the inter-caldera regions of the central TVZ where caldera-forming volcanism has ceased. This is inconsistent with interpretations drawn from the olivine data. We therefore suggest that harzburgitic xenocrysts originate from old depleted sub-continental lithospheric mantle (SCLM), which is present at depths of ~30 km in the south TVZ. By contrast, rifting and crustal thinning in the central TVZ has removed the SCLM, explaining why only xenocrysts of lherzolitic origin are found. The presence of depleted SCLM may act as a boundary layer inhibiting ascent of melt from the mantle, providing an explanation for lower erupted volumes in the south TVZ. Dissolution of the orthopyroxene component in harzburgite in the presence of hydrous melt satisfies major element constraints on south TVZ basalt (high SiO2, high MgO, low CaO/Al2O3). Taken together, this is the first mineralogical evidence for a tectonic and lithospheric control on the shift from andesitic to rhyolitic activity in the TVZ, implying a direct link between rifting, magma composition and volcanic productivity

Evidence for Low‐Pressure Crustal Anatexis During the Northeast Atlantic Break‐Up

While basaltic volcanism is dominant during rifting and continental breakup, felsic magmatism may be a significant component of some rift margins. During International Ocean Discovery Program (IODP) Expedition 396 on the continental margin of Norway, a graphite‐garnet‐cordierite bearing dacitic unit (the Mimir dacite) was recovered in two holes within early Eocene sediments on Mimir High (Site U1570), a marginal high on the Vøring Transform Margin. Here, we present a comprehensive textural, petrological, and geochemical study of the Mimir dacite in order to assess its origin and discuss the geodynamic implications. The major mineral phases (garnet, cordierite, quartz, plagioclase, alkali feldspar) are hosted in a fresh rhyolitic, vesicular, glassy matrix that is locally mingled with sediments. The major element chemistry of garnet and cordierite, the presence of zircon inclusions with inherited cores, and thermobarometric calculations all support an upper crustal metapelitic origin. While most magma‐rich margin models favor crustal anatexis in the lower crust, thermobarometric calculations performed here show that the Mimir dacite was produced at upper‐crustal depths (<5 kbar, 18 km depth) and high temperature (750–800°C) with up to 3 wt% water content. In situ U‐Pb analyses on zircon inclusions give a magmatic crystallization age of 54.6 ± 1.1 Ma, consistent with emplacement that post‐dates the Paleocene‐Eocene Thermal Maximum. Our results suggest that the opening of the Northeast Atlantic was associated with a phase of low‐pressure, high‐temperature crustal anatexis preceding the main phase of magmatism