Age and geochemistry of Late Neoproterozoic and Early Cambrian igneous rocks in southern New Brunswick: similarities and contrasts

Late Proterozoic to Early Cambrian igneous rocks are major components of the fault-bounded Caledonia, Brookville, and New River terranes of southern New Brunswick. As previously demonstrated, ca. 620 Ma and ca. 560– 550 Ma volcanic and plutonic rocks of the Caledonia terrane are petrologically similar to coeval units elsewhere in the Avalon terrane sensu stricto of the northern Appalachian orogen. In contrast, the Golden Grove Plutonic Suite and volcanic rocks of the Dipper Harbour Formation in the Brookville terrane are mainly younger, ranging in age from ca. 555 Ma to 525 Ma. A new U-Pb (zircon) age reported here confirms that rhyolite in the Dipper Harbour Formation crystallized at 553 ± 3 Ma, like the older units of the Golden Grove Plutonic Suite to which they are chemically similar. However, they differ chemically from felsic units of similar age in the Caledonia terrane, with higher K2O and Rb, lower Na2O, and negative epsilon Nd values, although they also appear to have formed in an extensional setting. The Early Cambrian history of the two terranes is also very different, with clastic sediment deposition dominating in the Caledonia terrane while an active continental margin subduction zone developed on the Brookville terrane. A U-Pb (zircon) age of 539 ± 4 Ma shows that volcanic rocks in the Simpsons Island Formation in the New River terrane are early Cambrian, similar to the ages of some plutons of the Golden Grove Plutonic Suite. More petrological studies of the Simpsons Island Formation are needed to assess it tectonic setting and relationship to the older (ca. 555 Ma) Leavitts Head Formation and Ragged Falls Plutonic Suite. These units are chemically similar to one another, consistent with their inferred comagmatic relationship, and are interpreted to have formed in an extensional setting. They are more similar to ca. 555– 545 Ma volcanic and plutonic rocks of the Brookville terrane than to 560– 550 Ma volcanic and plutonic rocks of the Caledonia terrane, although all of these units apparently formed in extensional settings. Too few data are available from volcanic units in the northeastern part of the New River terrane (Lobster Brook Formation) to compare them to the Leavitts Head Formation or to assess their tectonic setting. A U-Pb age of 622 ± 2 Ma from the Blacks Harbour Granite in the southern part of the New River terrane is similar to previously reported ages from the Lingley Suite in the northeastern part of the terrane. More mapping and sampling are needed to define the extent of these ca. 625 Ma units in the New River terrane and assess their tectonic setting, although a subduction environment is suggested by the available data. RÉSUMÉ Les roches ignées du Protérozoïque tardif au Cambrien précoce constituent des éléments importants des terranes limités par des failles de Caledonia, de Brookville et de New River dans le Sud du Nouveau-Brunswick. Il a déjà été démontré que les roches volcaniques et plutoniques d'environ 620 Ma et de 560 à 550 Ma du terrane de Caledonia sont pétrologiquement semblables aux unités contemporaines ailleurs à l'intérieur du terrane d'Avalon, faisant partie, au sens strict, du nord de l'orogène des Appalaches. Par contraste, le cortège plutonique de Golden Grove et les roches volcaniques de la Formation de Dipper Harbour dans le terrane de Brookville sont essentiellement plus récentes; leurs âges varient entre 755 Ma et 525 Ma. Une nouvelle datation au U-Pb (à partir de zircon) signalée aux présentes confirme que la rhyolite de la Formation de Dipper Harbour s'est cristallisée vers 553±3 Ma, tout comme les unités plus anciennes du cortège plutonique de Golden Grove auxquelles ces roches ressemblent sur le plan chimique. Elles diffèrent toutefois du point de vue chimique des unités felsiques d'âge analogue du terrane de Caledonia, en présentant des concentrations plus élevées de K2O et de Rb, des concentrations inférieures de Na2O, et des valeurs Nd epsilon négatives, même si elles semblent s'être formées dans un cadre d'extension. Le passé des deux terranes au cours du Cambrien précoce est également très différent : un dépôt de sédiments clastiques prédomine dans le terrane de Caledonia, tandis qu'une zone active de subduction de la marge continentale s'est développée dans le terrane de Brookville. Une datation au U-Pb (à partir de zircon) situant les roches volcaniques de la Formation de Simpsons Island dans le terrane de New River à 539 ±4 Ma, révèle qu'elles remontent au Cambrien, ce qui leur confère des âges semblables à certains plutons du cortège plutonique de Golden Grove. Il faudrait réaliser d'autres études pétrologiques de la Formation de Simpsons Island pour évaluer son cadre tectonique et ses rapports avec la Formation plus ancienne (environ 555 Ma) de Leavitts Head et le cortège plutonique de Ragged Falls. Ces unités sont chimiquement semblables les unes aux autres, ce qui correspond à leur présumée relation comagmatique. Elles sont interprétées comme des unités s'étant formées dans un cadre d'extension. Elles ressemblent plus aux roches plutoniques et volcaniques d'environ 555 à 545 Ma du terrane de Brookville qu'aux roches plutoniques et volcaniques de 560 à 550 Ma du terrane de Caledonia, même si ces unités se sont apparemment constituées dans des cadres d'extension. On dispose de trop peu de données des unités volcaniques du nord-est du terrane de New River (Formation de Lobster Brook) pour les comparer à la Formation de Leavitts Head ou pour évaluer leur cadre tectonique. L'âge au U-Pb de 622 ±2 Ma du granite de Blacks Harbour dans le sud du terrane de New River est semblable aux âges précédemment signalés dans le cas du cortège de Lingley dans le nord-est du terrane. D'autres travaux de cartographie et d'échantillonnage s'avèrent nécessaires pour définir l'étendue de ces unités d'environ 625 Ma dans le terrane de New River ainsi que pour évaluer leur cadre tectonique, même si les données dont on dispose laissent supposer un environnement de subduction

Granitoid plutons of the Brookville terrane, southern New Brunswick: petrology, age, and tectonic setting

Latest Neoproterozoic and Cambrian plutons in the Brookville terrane of southern New Brunswick are termed the Golden Grove Plutonic Suite. Four groups are recognized on the basis of composition: gabbro (2 plutons), diorite - granodiorite (17 plutons), granodiorite - monzogranite (8 plutons), and syenogranite - monzogranite (7 plutons). The dioritic to granodioritic and most of the granodioritic to monzogranitic plutons form linear trends on chemical variation diagrams, suggesting that magma evolution was dominated by plagioclase and amphibole fractionation. These plutons appear to constitute a typical I-type, calc-alkaline suite characteristic of continental margin subduction zones. This interpretation is supported by U-Pb zircon ages, which show that these plutons have ages between 540 Ma and 526 Ma. A new U-Pb age of 539.6 ± 1.2 Ma from one of the gabbroic plutons shows that the gabbroic plutons are co-genetic with the dioritic to granitic plutons, although they show varied ultramafic to anorthositic and dioritic compositions as a result of crystal accumulation. The syenogranitic to monzogranitic plutons and two of the granodioritic and monzogranitic plutons, as well as felsic volcanic rocks of the Dipper Harbour volcanic unit, show chemical trends that differ from the other plutons in having A-type characteristics. A U-Pb age of 548 ± 2 Ma for the Fairville Granite, as well as similar ages for a syenogranitic pluton and the Dipper Harbour volcanic unit, suggests that these units represent early stages of magmatism in the Golden Grove Plutonic Suite. RESUMÉ Les plutons du Cambrien et des périodes les plus anciennes du Néoprotérozoïque à l'intérieur du terrane de Brookville dans le Sud du Nouveau-Brunswick sont désignés sous le nom de « cortège plutonique de Golden Grove ». On y distingue quatre groupes en fonction de leur composition : ceux à base de gabbro (deux plutons), de diorite - granodiorite (17 plutons), de granodiorite - monzogranite (huit plutons) et de syénogranite - monzogranite (sept plutons). Les plutons dioritiques à granodioritiques et la majorité des plutons granodioritiques à monzogranitiques forment des tracés linéaires sur les schémas de diversité de la composition chimique, ce qui laisse supposer que l'évolution magmatique a été dominée par une cristallisation fractionnée des plagioclases et des amphiboles. Ces plutons semblent constituer un cortège calco-alcalin intrusif typique, caractéristique des zones de subduction de la marge continentale. Cette interprétation est corroborée par la datation au U-Pb, obtenue à partir de zircon, qui révèle que ces plutons ont des âges entre 540 Ma et 526 Ma. Une nouvelle datation au U-Pb obtenue à partir de zircon situant à 539,6 ± 1,2 Ma l'âge de l'un des plutons gabbroïques, signale que les plutons gabbroïques sont cogénétiques avec les plutons dioritiques à granitiques, même s'ils présentent des compositions ultramafi ques à anorthositiques et dioritiques diversifi ées par suite d'une accumulation de cristaux. Les plutons syénogranitiques à monzogranitiques et deux des plutons granodioritiques et monzogranitiques, de même que les roches volcanofelsiques de l'unité volcanique de Dipper Harbour, livrent des tracés chimiques différents des autres plutons du fait qu'ils possèdent les caractéristiques des plutons de type anorogénique. L'âge au U-Pb de 548 ± 2 Ma du granite de Fairville ainsi que les âges similaires d'un pluton syénogranitique et de l'unité volcanique de Dipper Harbour permettent de supposer que ces unités représentent les stades précoces du magmatisme à l'intérieur du cortège plutonique de Golden Grove

Reducing the Risk of Invasive Pathogens to Wildlife Health in the United States

Call to Action In keeping with action items 4.3.1 and 4.3.2 of the 2016–2018 National Invasive Species Council (NISC) Management Plan, the Wildlife Health Task Team of the Invasive Species Advisory Committee (ISAC) was charged with: 1) identifying the major areas of vulnerability to native wildlife from the introduction and spread of invasive pathogens, and 2) making recommendations to address these vulnerabilities, including through potential changes in statute, regulation, policy, or practice of the relevant agencies

Enhanced Detection of Community-Acquired Pneumonia Pathogens With the BioFire® Pneumonia FilmArray® Panel.

Background: Although most observational studies identify viral or bacterial pathogens in 50% or less of patients hospitalized with community-acquired pneumonia (CAP), we previously demonstrated that a multi-test bundle (MTB) detected a potential pathogen in 73% of patients. This study compares detection rates for potential pathogens with the MTB versus the Biofire® Pneumonia FilmArray® panel (BPFA) multiplex PCR platform and presents an approach for integrating BPFA results as a foundation for subsequent antibiotic stewardship (AS) activities. Methods: Between January 2017 to March 2018, all patients admitted for CAP were enrolled. Patients were considered evaluable if all elements of the MTB and the BPFA were completed, and they met other a priori inclusion criteria. The primary endpoint was the percentage of potential pathogens detected using the MTB (8 viral and 6 bacterial targets) versus the BPFA (8 viral and 18 bacterial targets). Blood and sputum cultures were performed on all patients. Two or more procalcitonin (PCT) levels assisted clinical assessments as to whether detected bacteria were invading or colonizing. Results: Of 585 enrolled patients, 274 were evaluable. A potential viral pathogen was detected in 40.5% with MTB versus 60.9% of patients with BPFA with an odds ratio (95% CI) of 9.00 (4.12 to 23.30) p\u3c0.01. A potential bacterial pathogen was identified in 66.4% with the MTB vs 75.5% with the BPFA odds ratio (95% CI) of 2.09 (1.24 to 3.59), p 0.003). Low PCT levels helped identify detected bacteria as colonizers. Keywords: Community-acquired pneumonia; diagnostics; filmarray; pneumonia; procalcitonin

Status of the LUX Dark Matter Search

The Large Underground Xenon (LUX) dark matter search experiment is currently being deployed at the Homestake Laboratory in South Dakota. We will highlight the main elements of design which make the experiment a very strong competitor in the field of direct detection, as well as an easily scalable concept. We will also present its potential reach for supersymmetric dark matter detection, within various timeframes ranging from 1 year to 5 years or more.Comment: 4 pages, in proceedings of the SUSY09 conferenc

A low-memory algorithm for finding short product representations in finite groups

We describe a space-efficient algorithm for solving a generalization of the subset sum problem in a finite group G, using a Pollard-rho approach. Given an element z and a sequence of elements S, our algorithm attempts to find a subsequence of S whose product in G is equal to z. For a random sequence S of length d log_2 n, where n=#G and d >= 2 is a constant, we find that its expected running time is O(sqrt(n) log n) group operations (we give a rigorous proof for d > 4), and it only needs to store O(1) group elements. We consider applications to class groups of imaginary quadratic fields, and to finding isogenies between elliptic curves over a finite field.Comment: 12 page

The Lyman Continuum Escape Fraction of Galaxies and AGN in the GOODS Fields

We present our analysis of the LyC emission and escape fraction of 111 spectroscopically verified galaxies with and without AGN from $2.26<z<4.3$. We extended our ERS sample from Smith et al. (2018; arXiv:1602.01555) with 64 galaxies in the GOODS North and South fields using WFC3/UVIS F225W, F275W, and F336W mosaics we independently drizzled using the HDUV, CANDELS, and UVUDF data. Among the 17 AGN from the 111 galaxies, one provided a LyC detection in F275W at $m_{AB}=23.19$ mag (S/N $\simeq$ 133) and $GALEX$ NUV at $m_{AB}=23.77$ mag (S/N $\simeq$ 13). We simultaneously fit $SDSS$ and $Chandra$ spectra of this AGN to an accretion disk and Comptonization model and find $f_{esc}$ values of $f_{esc}^{F275W}\simeq 28^{+20}_{-4}$% and $f_{esc}^{NUV}\simeq 30^{+22}_{-5}$%. For the remaining 110 galaxies, we stack image cutouts that capture their LyC emission using the F225W, F275W, and F336W data of the GOODS and ERS samples, and both combined, as well as subsamples of galaxies with and without AGN, and $all$ galaxies. We find the stack of 17 AGN dominate the LyC production from $\langle z\rangle\simeq 2.3-4.3$ by a factor of $\sim$10 compared to all 94 galaxies without AGN. While the IGM of the early universe may have been reionized mostly by massive stars, there is evidence that a significant portion of the ionizing energy came from AGN.Comment: 36 pages, 17 figures, 5 tables. Accepted for publication in The Astrophysical Journal. v1 abstract latex errors corrected, minor changes to table 5, orcid ID corrected for one autho

Photometric properties of Local Volume dwarf galaxies

We present surface photometry and metallicity measurements for 104 nearby dwarf galaxies imaged with the Advanced Camera for Surveys and Wide Field and Planetary Camera 2 aboard the Hubble Space Telescope. In addition, we carried out photometry for 26 galaxies of the sample and for Sextans B on images of the Sloan Digital Sky Survey. Our sample comprises dwarf spheroidal, irregular and transition type galaxies located within ~10 Mpc in the field and in nearby groups: M81, Centaurus A, Sculptor, and Canes Venatici I cloud. It is found that the early-type galaxies have on average higher metallicity at a given luminosity in comparison to the late-type objects. Dwarf galaxies with M_B > -12 -- -13 mag deviate toward larger scale lengths from the scale length -- luminosity relation common for spiral galaxies, h \propto L^{0.5}_B. The following correlations between fundamental parameters of the galaxies are consistent with expectations if there is pronounced gas-loss through galactic winds: 1) between the luminosity of early-type dwarf galaxies and the mean metallicity of constituent red giant branch stars, Z ~ L^0.4, 2) between mean surface brightness within the 25 mag/sq.arcsec isophote and the corresponding absolute magnitude in the V and I bands, SB_25 ~ 0.3 M_25, and 3) between the central surface brightness (or effective surface brightness) and integrated absolute magnitude of galaxies in the V and I bands, SB_0 ~ 0.5 M_L, SB_e ~ 0.5 M_e. The knowledge of basic photometric parameters for a large sample of dwarf galaxies is essential for a better understanding of their evolution.Comment: 14 pages, 11 figures, 2 tables, MNRAS accepte

Levels of Abnormal Prion Protein in Deer and Elk with Chronic Wasting Disease

Infected deer may pose a higher risk than elk for disease transmission