Application of palynological data to the chronology of the Palaeogene lava fields of the British Province: implications for magmatic stratigraphy

New high-precision ages, determined from palynomorph assemblages within intercalated sedimentary deposits, are presented for the Palaeogene lava fields (Skye, Mull and Antrim) of the British Province. These data reveal very rapid averaged eruption rates (1 m/200 yr) and the non-synchronous formation of the lava fields. Eruption of the volumetrically dominant transitional to mildly alkaline lavas of the Skye (58.25-58.0 Ma) and Mull (post 55 Ma) lava fields is separated by the eruption of the MORB-like Preshal More flows of olivine tholeiite found at the top of the preserved sequence on Skye and at the base of the Mull Lava Field. The Lower Formation of the Antrim Lava Field correlates with the Skye Lava Field and the Upper Formation correlates with the Preshal More flows. The new ages indicate that the eruption of the Preshal More flows was synchronous with the main ocean floor spreading event which occurred 500 km to the NW, at c. 55 Ma, during Chron 24r. A combined thinspot and channelized plume model may best explain the temporal and spatial distributions of the lava fields and associated subvolcanic complexes of the British Province

Molecular parameters of post impact cooling in the Boltysh impact structure

Impact events have the potential to generate a number of long-term sources of heat that can lead to the initiation of hydrothermal systems when the impact occurs on a water- or ice-rich target. Such hydrothermal systems have been postulated as promising locations to search for evidence of past biological processes on Mars due to the prevalence of impact cratering as a surface process in Mars’s early history. In this study, we have used molecular parameters of the thermal maturity of organic matter combined with palynology and carbon isotope stratigraphy to study the post impact thermal history of crater fill sediments from the Boltysh crater, Ukraine

A Survey of Aquatic Invertebrate Communities in Nebraska Sandhill Lakes Reveals Potential Alternative Ecosystem States

Aquatic invertebrate communities are important to shallow lake ecosystem form and function, providing vital components to the food web and thereby important to achieving lake management goals. We characterized lake invertebrate communities and physicochemical variables in six Nebraska Sandhill lakes and examined these characteristics within an alternative stable state framework. Surveys were conducted during 2005 within each of these lakes by sampling aquatic macroinvertebrate abundance, zooplankton abundance and biomass, phytoplankton biomass, and physicochemical variables. When placed within an alternative stable state framework, the response variables exhibited a gradient of different ecosystem states. Two lakes appeared congruent with the clear water state (dense submergent vegetation, high invertebrate abundance and diversity, and low phytoplankton), two lakes were congruent with the turbid water state (high phytoplankton, low vegetation coverage, and low invertebrate abundance and diversity), and two lakes were intermediate, likely in a state of hysteresis (i.e., multiple states under equal environmental conditions). Principal component groupings further supported these findings by following similar lakespecific patterns with attributes of each stable state grouping meaningfully according to the observed lake states. The lakes contained varied fish communities, potentially influencing many measured metrics, through a top-down mechanism. Generally, lakes dominated by piscivorous fish displayed the clear water state, whereas lakes with abundant planktivores displayed the turbid water state. Shallow lakes containing dense invertebrate communities likely provide a rich food base to important fauna (migratory waterfowl) that aid in reaching desired management objectives for these systems. Multiple small lakes, in proximity, displaying divergent ecosystem states invites the opportunity for more in-depth analyses of driving mechanisms that will undoubtedly add to our ability to effectively manage these systems in the future

The Boltysh impact crater, Ukraine: smectites from the crater-fill suevites

The Boltysh crater has an entire suite of crater-fill impactites preserved, including two impact melt- bearing breccias. Smectite occurrence in the breccias suggests two stages of alteration; an early hydrothermal mineralization, and a later, low temperature weathering. δD and δ18O of smectite separates are currently being measured and will be presented

Post-impact heating of a crater lake

Lacustrine sediments from the 24 km diameter Boltysh impact structure record the rapid formation of an intra-crater lake. Stable isotope compositions and organic maturity parameters from the lake sediments deposited post-impact show that they were heated by underlying impactites. This heating is attributed to the establishment of an impact- generated hydrothermal system. Estimates of the duration of heating are ~30 – 40 k.y. consistent with the suggestion that crater lakes extend the longevity of impact-generated hydrothermal systems

High-precision U-Pb zircon dating of explosive volcanism in an early bi-modal volcano-sedimentary sequence from the Isle of Mull, North Atlantic Igneous Province

The North Atlantic Igneous Province (NAIP) forms one of the best studied Large Igneous Provinces (LIP) on the planet, however, significant uncertainties regarding the age and nature of the early onset of volcanism across the province remain. In order to better understand the onset and timing of volcanism within the NAIP, we present a new study of the mixed volcano-sedimentary deposits exposed at the base of the Isle of Mull lava pile, Inner Hebrides, Scotland. The study area comprises organic rich estuarine sediments, intimately mixed and interdigitated with bi-modal composition volcaniclastic and pyroclastic interlayers, including a prominent stratigraphically constrained c. 30 cm thick water-lain rhyolitic ignimbrite. Pristine magmatic zircons liberated from the ignimbrite reveal a high precision Usingle bondPb age of 62.035 ± 0.041 Ma (2σ) giving a robust age for early volcanism in this part of the province. Field observations reveal evidence for mafic phreatomagmatic eruptive deposits both above and below the rhyolite documenting the bimodal explosive nature of the initial magmatism in this area and, importantly, that mafic magmatism initiated before the dated unit. The bi-modal explosive eruptions periodically inundated an otherwise quiet and low energy Danian aged estuarine environment prior to its inundation with lava as magmatism took hold in the region

Collaborative International Research in Clinical and Longitudinal Experience Study in NMOSD

OBJECTIVE: To develop a resource of systematically collected, longitudinal clinical data and biospecimens for assisting in the investigation into neuromyelitis optica spectrum disorder (NMOSD) epidemiology, pathogenesis, and treatment. METHODS: To illustrate its research-enabling purpose, epidemiologic patterns and disease phenotypes were assessed among enrolled subjects, including age at disease onset, annualized relapse rate (ARR), and time between the first and second attacks. RESULTS: As of December 2017, the Collaborative International Research in Clinical and Longitudinal Experience Study (CIRCLES) had enrolled more than 1,000 participants, of whom 77.5% of the NMOSD cases and 71.7% of the controls continue in active follow-up. Consanguineous relatives of patients with NMOSD represented 43.6% of the control cohort. Of the 599 active cases with complete data, 84% were female, and 76% were anti-AQP4 seropositive. The majority were white/Caucasian (52.6%), whereas blacks/African Americans accounted for 23.5%, Hispanics/Latinos 12.4%, and Asians accounted for 9.0%. The median age at disease onset was 38.4 years, with a median ARR of 0.5. Seropositive cases were older at disease onset, more likely to be black/African American or Hispanic/Latino, and more likely to be female. CONCLUSION: Collectively, the CIRCLES experience to date demonstrates this study to be a useful and readily accessible resource to facilitate accelerating solutions for patients with NMOSD

Novel loci affecting iron homeostasis and their effects in individuals at risk for hemochromatosis

Variation in body iron is associated with or causes diseases, including anaemia and iron overload. Here, we analyse genetic association data on biochemical markers of iron status from 11 European-population studies, with replication in eight additional cohorts (total up to 48,972 subjects). We find 11 genome-wide-significant (P<5 × 10(-8)) loci, some including known iron-related genes (HFE, SLC40A1, TF, TFR2, TFRC, TMPRSS6) and others novel (ABO, ARNTL, FADS2, NAT2, TEX14). SNPs at ARNTL, TF, and TFR2 affect iron markers in HFE C282Y homozygotes at risk for hemochromatosis. There is substantial overlap between our iron loci and loci affecting erythrocyte and lipid phenotypes. These results will facilitate investigation of the roles of iron in disease