Hf–Zr anomalies in clinopyroxene from mantle xenoliths from France and Poland: implications for Lu–Hf dating of spinel peridotite lithospheric mantle

Clinopyroxenes in some fresh anhydrous spinel peridotite mantle xenoliths from the northern Massif Central (France) and Lower Silesia (Poland), analysed for a range of incompatible trace elements by laser ablation inductively coupled plasma mass spectrometry, show unusually strong negative anomalies in Hf and Zr relative to adjacent elements Sm and Nd, on primitive mantle-normalised diagrams. Similar Zr–Hf anomalies have only rarely been reported from clinopyroxene in spinel peridotite mantle xenoliths worldwide, and most are not as strong as the examples reported here. Low Hf contents give rise to a wide range of Lu/Hf ratios, which over geological time would result in highly radiogenic εHf values, decoupling them from εNd ratios. The high 176Lu/177Hf could in theory produce an isochronous relationship with 176Hf/177Hf over time; an errorchron is shown by clinopyroxene from mantle xenoliths from the northern Massif Central. However, in a review of the literature, we show that most mantle spinel peridotites do not show such high Lu/Hf ratios in their constituent clinopyroxenes, because they lack the distinctive Zr–Hf anomaly, and this limits the usefulness of the application of the Lu–Hf system of dating to garnet-free mantle rocks. Nevertheless, some mantle xenoliths from Poland or the Czech Republic may be amenable to Hf-isotope dating in the future

Metasomatic effects in the lithospheric mantle beneath the NE Bohemian Massif: a case study of Lutynia (SW Poland) peridotite xenoliths

Spinel lherzolite and spinel harzburgite mantle xenoliths occur in the 4.56 ± 0.2 Ma Lutynia basanite in SW Poland. Only one studied xenolith contains minor pargasitic amphibole. Minerals forming the xenoliths are chemically unzoned. Olivine (Fo [(Mg / (Mg + Fetot)) * 100] 89.8–92.4) contains 0.34–0.45 wt.% NiO and < 780 ppm Ca; orthopyroxene is Al enstatite (#mg [(Mg / (Mg + Fetot) * 100] 0.90–0.92, Al 0.06–0.17 a.pfu); clinopyroxene is Al–Cr diopside (#mg 0.91–0.93, Al 0.104–0.197 a.pfu). Exsolved orthopyroxene occurs in the clinopyroxene and vice versa. Al–Mg spinel occurs in symplectites with clinopyroxene. Second generation crystals of olivine (Fo88.0–91.7, Ca up to 1800 ppm), clinopyroxene and spinel occur in small interstitial patches containing feldspar. Clinopyroxene II is Al-poor (0.018–0.070 a.pfu, #mg 0.921–0.932) when coexisting with alkali feldspar, but Al-rich (0.046–0.261 a.pfu; #mg 0.907–0.925) when found with plagioclase. Four types of REE (rare earth elements) patterns are found in the clinopyroxene: (group A) flat HREE (heavy REE) with LREE (light REE) content increasing smoothly; (group B) flat HREE with an abrupt increase of MREE (medium REE) and LREE; (group C) LREE-enriched, flat HREE with negative inflection at MREE; (group D) smoothly LREE-enriched with no flat HREE pattern. The exception is clinopyroxene from xenolith MM30 which is extremely depleted in LREE. Clinopyroxene I from all the xenoliths (excluding MM30) contains high amounts of Th and U. Clinopyroxene trace element compositions record 8–15% of partial melting. Major and trace element compositions of minerals record later cryptic metasomatism induced by a CO2-bearing alkaline melt. Variable REE patterns for clinopyroxene I from groups A, B and C are due to chromatographic enrichment, with group A peridotites located close to the metasomatic source and group C being the furthest. The pargasite-bearing MM04 was probably the closest to the metasomatic source and thus recorded incipient modal metasomatism. Clinopyroxene–spinel symplectites and ortho-/clinopyroxene exsolutions suggest that the peridotites were transported from the garnet-lherzolite facies into the spinel one where they cooled and equilibrated at 960–1000 °C. The patches formed by the second generation of minerals are the effect of pre-eruption infiltration by the basanitic melt

Supernova Model Discrimination with Hyper-Kamiokande

Core-collapse supernovae are among the most magnificent events in the observable universe. They produce many of the chemical elements necessary for life to exist and their remnants—neutron stars and black holes—are interesting astrophysical objects in their own right. However, despite millennia of observations and almost a century of astrophysical study, the explosion mechanism of core-collapse supernovae is not yet well understood. Hyper-Kamiokande is a next-generation neutrino detector that will be able to observe the neutrino flux from the next galactic core-collapse supernova in unprecedented detail. We focus on the first 500 ms of the neutrino burst, corresponding to the accretion phase, and use a newly-developed, high-precision supernova event generator to simulate Hyper-Kamiokandeʼs response to five different supernova models. We show that Hyper-Kamiokande will be able to distinguish between these models with high accuracy for a supernova at a distance of up to 100 kpc. Once the next galactic supernova happens, this ability will be a powerful tool for guiding simulations toward a precise reproduction of the explosion mechanism observed in nature

Are hospitalized or ambulatory patients with heart failure treated in accordance with European Society of Cardiology guidelines? Evidence from 12 440 patients of the ESC Heart Failure Long-Term Registry.

AIMS: To evaluate how recommendations of European guidelines regarding pharmacological and non-pharmacological treatments for heart failure (HF) are adopted in clinical practice. METHODS AND RESULTS: The ESC-HF Long-Term Registry is a prospective, observational study conducted in 211 Cardiology Centres of 21 European and Mediterranean countries, members of the European Society of Cardiology (ESC). From May 2011 to April 2013, a total of 12 440 patients were enrolled, 40.5% with acute HF and 59.5% with chronic HF. Intravenous treatments for acute HF were heterogeneously administered, irrespective of guideline recommendations. In chronic HF, with reduced EF, renin-angiotensin system (RAS) blockers, beta-blockers, and mineralocorticoid antagonists (MRAs) were used in 92.2, 92.7, and 67.0% of patients, respectively. When reasons for non-adherence were considered, the real rate of undertreatment accounted for 3.2, 2.3, and 5.4% of the cases, respectively. About 30% of patients received the target dosage of these drugs, but a documented reason for not achieving the target dosage was reported in almost two-thirds of them. The more relevant reasons for non-implantation of a device, when clinically indicated, were related to doctor uncertainties on the indication, patient refusal, or logistical/cost issues. CONCLUSION: This pan-European registry shows that, while in patients with acute HF, a large heterogeneity of treatments exists, drug treatment of chronic HF can be considered largely adherent to recommendations of current guidelines, when the reasons for non-adherence are taken into account. Observations regarding the real possibility to adhere fully to current guidelines in daily clinical practice should be seriously considered when clinical practice guidelines have to be written