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When Ragnarok--the apocalypse--threatens, the human descendants of the gods band together to fight monsters, and Matt Thorsen and his friends must journey to the underworld to save a descendant.

National levels of personal health-care access and quality can be approximated by measuring mortality rates from causes that should not be fatal in the presence of effective medical care (ie, amenable mortality). Previous analyses of mortality amenable to health care only focused on high-income countries and faced several methodological challenges. In the present analysis, we use the highly standardised cause of death and risk factor estimates generated through the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) to improve and expand the quantification of personal health-care access and quality for 195 countries and territories from 1990 to 2015. We mapped the most widely used list of causes amenable to personal health care developed by Nolte and McKee to 32 GBD causes. We accounted for variations in cause of death certification and misclassifications through the extensive data standardisation processes and redistribution algorithms developed for GBD. To isolate the effects of personal health-care access and quality, we risk-standardised cause-specific mortality rates for each geography-year by removing the joint effects of local environmental and behavioural risks, and adding back the global levels of risk exposure as estimated for GBD 2015. We employed principal component analysis to create a single, interpretable summary measure–the Healthcare Quality and Access (HAQ) Index–on a scale of 0 to 100. The HAQ Index showed strong convergence validity as compared with other health-system indicators, including health expenditure per capita (r=0·88), an index of 11 universal health coverage interventions (r=0·83), and human resources for health per 1000 (r=0·77). We used free disposal hull analysis with bootstrapping to produce a frontier based on the relationship between the HAQ Index and the Socio-demographic Index (SDI), a measure of overall development consisting of income per capita, average years of education, and total fertility rates. This frontier allowed us to better quantify the maximum levels of personal health-care access and quality achieved across the development spectrum, and pinpoint geographies where gaps between observed and potential levels have narrowed or widened over time. Between 1990 and 2015, nearly all countries and territories saw their HAQ Index values improve; nonetheless, the difference between the highest and lowest observed HAQ Index was larger in 2015 than in 1990, ranging from 28·6 to 94·6. Of 195 geographies, 167 had statistically significant increases in HAQ Index levels since 1990, with South Korea, Turkey, Peru, China, and the Maldives recording among the largest gains by 2015. Performance on the HAQ Index and individual causes showed distinct patterns by region and level of development, yet substantial heterogeneities emerged for several causes, including cancers in highest-SDI countries; chronic kidney disease, diabetes, diarrhoeal diseases, and lower respiratory infections among middle-SDI countries; and measles and tetanus among lowest-SDI countries. While the global HAQ Index average rose from 40·7 (95% uncertainty interval, 39·0–42·8) in 1990 to 53·7 (52·2–55·4) in 2015, far less progress occurred in narrowing the gap between observed HAQ Index values and maximum levels achieved; at the global level, the difference between the observed and frontier HAQ Index only decreased from 21·2 in 1990 to 20·1 in 2015. If every country and territory had achieved the highest observed HAQ Index by their corresponding level of SDI, the global average would have been 73·8 in 2015. Several countries, particularly in eastern and western sub-Saharan Africa, reached HAQ Index values similar to or beyond their development levels, whereas others, namely in southern sub-Saharan Africa, the Middle East, and south Asia, lagged behind what geographies of similar development attained between 1990 and 2015. This novel extension of the GBD Study shows the untapped potential for personal health-care access and quality improvement across the development spectrum. Amid substantive advances in personal health care at the national level, heterogeneous patterns for individual causes in given countries or territories suggest that few places have consistently achieved optimal health-care access and quality across health-system functions and therapeutic areas. This is especially evident in middle-SDI countries, many of which have recently undergone or are currently experiencing epidemiological transitions. The HAQ Index, if paired with other measures of health-system characteristics such as intervention coverage, could provide a robust avenue for tracking progress on universal health coverage and identifying local priorities for strengthening personal health-care quality and access throughout the world. Bill & Melinda Gates Foundation.

Meta-sedimentary rocks recovered beneath Palaeogene basalts near the base of Ocean Drilling Program (ODP) Leg 152-917A offshore South-East Greenland were thought to be of Late Cretaceous age. This interpretation, however, has several inconsistencies as it requires a tectono-metamorphic event during the Cretaceous not recognized in the North Atlantic region, and the presence of a wide Mesozoic sedimentary basin that extended from SE-Greenland to the Rockall Plateau, for which there is currently no evidence. Here, we report a Neoproterozoic U/Pb apatite age of 905 ± 21 Ma and a younger 40Ar/39Ar isochron whole-rock age of 820 ± 40 Ma for an altered tuff layer that occurs in the upper part of the meta-volcaniclastic sequence recovered from hole 917A. The 40Ar/39Ar step-heating ages on biotite and whole-rock mini-cores from deeper in hole 917A yielded Palaeoproterozic dates that cluster around 1950 to 1850 Ma, pointing toward a Palaeoproterozoic source. The U/Pb apatite date is interpreted as the eruption age of the tuff layer, whereas the younger whole-rock 40Ar/39Ar age is consistent with low-temperature greenschist alteration of volcanic glass and secondary mineral growth during sedimentary burial in an extensional regime. The c. 905 Ma age for the tuff provides the first evidence for Neoproterozoic rocks offshore South-East Greenland and suggests a correlation between this sequence and the Torridon Group in the Hebridean Foreland of the Scottish Caledonides. The calc-alkaline nature of the volcaniclastic rocks and the age of the tuff layer point toward a source area with arc-magmatism related to the Renlandian event of the Valhalla Orogeny.

Titanium can be incorporated either tetrahedrally (IVTi) or octahedrally (VITi) in most silicate minerals. Ti K-edge X-ray absorption fine structure (XAFS) spectroscopy enables observation of Ti coordination in minerals and melts. In this study, XAFS is used to determine the coordination of Ti in synthetic and natural garnets. Garnets grown synthetically at eclogite- and granulite-facies conditions can contain several wt% TiO2, most of which is incorporated as VITi. This observation aligns with major element trends in these garnets. In natural garnets grown at lower temperatures and pressures, on the other hand, Ti is observed to occupy both the octahedral and tetrahedral sites in garnet-in some cases Ti is almost entirely fourfold coordinated. Combined with previous research (see Ackerson et al. 2017, this issue) on substitution mechanisms for VITi, the results of this study demonstrate that Ti is incorporated on two crystallographic sites in garnet by at least three primary substitution mechanisms. In both natural and synthetic garnets, there is a discernible increase in VITi content in garnet with increasing temperature and pressure, suggesting a significant role for these two parameters in determining Ti solubility. However, a continuous increase in VITi with increasing grossular content also suggests that the Ca content of the garnet plays a critical role.

The mineralogical, petrological, geochemical and geochronological data were used to evaluate the age and petrogenesis of compositionally contrasting metamorphic rocks at the junction between Meso-Neoproterozoic Transangarian structures and Archean-Paleoproterozoic complexes of the Angara–Kan inlier of the Yenisei Ridge. The studied metabasites and metapelites provide clues for understanding the evolution of the region. The magmatic protoliths of low-Ti metabasites were derived by melting of depleted (N-MORB) upper mantle, and their high-Ti counterparts are interpreted to have originated from an enriched mantle source (E-MORB). The petrogeochemical characteristics of protoliths of the metabasite dikes resemble those of within-plate basalts and ocean island tholeiites. The Fe- and Al-rich metapelites are redeposited and metamorphosed products of Precambrian weathering crusts of kaolinite and montmorillonite-chlorite-hydromica compositions. The Р–Т conditions of metamorphism (4.9–5.5 kbar/570–650°С for metabasites; 4.1–7.1 kbar/500–630°С for metapelites) correspond to epidote–amphibolite to amphibolite facies transition. The evolution of the Angara complex occurred in two stages. The early stage (1.18–0.85 Ga) is associated with Grenville tectonics and the late stage is correlated with accretion/collision episodes of the Valhalla orogeny, with the peaks at 810–790 and 730–720 Ma, and the final stage of the Neoproterozoic evolution of the orogen on the southwestern margin of the Siberian craton. The correlation of regional crustal processes with globalscale geological events in the Precambrian evolution of the Earth supports recent paleomagnetic reconstructions that allow a direct, long-lived (1400–600 Ma) spatial and temporal connection between Siberia, Laurentia, and Baltica, which have been parts of ancient supercontinents.

The Valhalla uranium deposit, located 40 km north of Mount Isa, Queensland, Australia, is an albitite-hosted, Mesoproterozoic U deposit similar to albitite-hosted uranium deposits in the Ukraine, Sweden, Brazil and Guyana. Uranium mineralisation is hosted by a thick package of interbedded fine-grained sandstones, arkoses and gritty siltstones that are bound by metabasalts belonging to the ca. 1,780 Ma Eastern Creek Volcanics in the Western Succession of the Mount Isa basin. Alteration associated with U mineralisation can be divided into an early, main and late stage. The early stage is dominated by laminated and intensely altered rock comprising albite, reibeckite, calcite, (titano)magnetite ± brannerite. The main stage of mineralisation is dominated by brecciated and intensely altered rocks that comprise laminated and intensely altered rock cemented by brannerite, apatite, (uranoan)-zircon, uraninite, anatase, albite, reibeckite, calcite and hematite. The late stage of mineralisation comprises uraninite, red hematite, dolomite, calcite, chlorite, quartz and Pb-, Fe-, Cu-sulfides. Brannerite has U–Pb and Pb–Pb ages that indicate formation between 1,555 and 1,510 Ma, with significant Pb loss evident at ca. 1,200 Ma, coincident with the assemblage of Rodinia. The oldest ages of the brannerite overlap with 40 Ar/ 39 Ar ages of 1,533 ± 9 Ma and 1,551 ± 7 Ma from early and main-stage reibeckite and are interpreted to represent the timing of formation of the deposit. These ages coincide with the timing of peak metamorphism in the Mount Isa area during the Isan Orogeny. Lithogeochemical assessment of whole rock data that includes mineralised and unmineralised samples from the greater Mount Isa district reveals that mineralisation involved the removal of K, Ba and Si and the addition of Na, Ca, U, V, Zr, P, Sr, F and Y. U/Th ratios indicate that the ore-forming fluid was oxidised, whereas the crystal chemistry of apatite and reibeckite within the ore zone suggests that F − and were important ore-transporting complexes. δ 18 O values of co-existing calcite and reibeckite indicate that mineralisation occurred between 340 and 380°C and involved a fluid having δ 18 O fluid values between 6.5 and 8.6‰. Reibeckite δD values reveal that the ore fluid had a δD fluid value between −98 and −54‰. The mineral assemblages associated with early and main stages of alteration, plus δ 18 O fluid and δD fluid values, and timing of the U mineralisation are all very similar to those associated with Na–Ca alteration in the Eastern Succession of the Mount Isa basin, where a magmatic fluid is favoured for this style of alteration. However, isotopic data from Valhalla is also consistent with that from the nearby Mount Isa Cu deposit where a basinal brine is proposed for the transport of metals to the deposit. Based on the evidence to hand, the source fluids could have been derived from either or both the metasediments that underlie the Eastern Creek Volcanics or magmatism that is manifest in the Mount Isa area as small pegmatite dykes that intruded during the Isan Orogeny.

Two new species of bairdiid Ostracoda are described from the lower Barremian – Hauterivian interval of the Valhall and Åsgard formations in the northern and central North Sea and Atlantic margin off Norway. The new species are Pontocyprella valhalla (lsid:zoobank.org:act:CA6B273F-CFF6-4C38-B9F4-18188225A711, 18 January 2018) and Bairdia asgarda (lsid:zoobank.org:act:4A4DC817-A028-45FB-9287-ABF3794F2FCB, 18 January 2018). These species dominate the ostracod assemblage that occurs abundantly in early Barremian–Hauterivian deep marine sediments of the northern and central North Sea and Haltenbanken area off Norway. Pontocyprella valhalla is restricted to this interval and because of its large size and distinct shape is a useful stratigraphic marker species, its last appearance being within the early Barremian.

The new results of U–Pb and 40 Ar/ 39 Ar dating and petrological and geochemical studies of rocks from the Yenisey regional shear zone (YRSZ) in the Transangarian part of the Yenisey Ridge were used to identify a dike belt at the western margin of the Siberian craton and constrain the timing of formation of rift-related structures accompanied by within-plate magmatism. The magmatism of this epoch produced felsic and mafic intrusive rocks. The extension processes are recorded by the 797–787 Ma dike swarms. The rift origin of the rocks studied here is confirmed by their occurrence as dikes and sills confined to the YRSZ, bimodal composition of magmatic rock associations, and petrochemical characteristics of rocks typical of within-plate settings. The formation of the 800 Ma dike belt within the study area could be associated with the Neoproterozoic extensional tectonic events along the western margin of the Siberian craton which coincided with the onset of the breakup of the Rodinia supercontinent. These events provide the upper age limit for the collisional metamorphism that took place at the final stage of orogeny. The evolutionary phases identified in the region agree well with the sequence and style of tectonothermal events within the Valhalla Orogen at the Arctic margin of Rodinia and provide further support for the spatial proximity between Siberia and North Atlantic cratons during this epoch, as indicated by recent paleomagnetic data.

Albitite-type uranium deposits are widely distributed, usually of low grade (<1% U3O8), but are often large and collectively contain over 1 million tonnes of U3O8. Uranium is hosted in a wide range of metamorphic lithologies, whose only common characteristic is that they have been extensively mylonitised. Ore minerals are disseminated and rarely in megascopic veins, within and adjacent to albitised mylonites. Grain size is uniformly fine, generally less than 50 microns. Scanning electron microscopy reveals that spatial association between uranium and various Ti-bearing phases is common. Gangue minerals include albite, carbonates (calcite and dolomite), and sodic pyroxene and amphibole. The ore rarely contains economic metals apart from uranium, phosphorous at Itataia being an exception. There is widespread evidence of hydrothermal zirconium mobility and hydrothermal zircon and other Zr phases are frequent and in some cases abundant gangue minerals. Positive correlations are noted between uranium and various high field strength elements. The group remains poorly described and understood, but a link to iron-oxide copper-gold (IOCG) deposits and/or carbonatite and/or alkaline magmatism is plausible.