1,720,975 research outputs found
Boron isotopes in tourmaline from hydrothermal ore systems
No full textA new compilation of published data on the boron isotope composition of hydrothermal tourmaline is presented here. The database is provided in the excel file (Trumbull_etal_B-isotopes_Tourmaline_OreDeposits.xlsx) and contains ca. 4000 boron isotope analyses of tourmaline gathered from 57 publications (see References.docx), as well as additional information about the deposit, host rocks, age and temperature of the mineralization, particulars of tourmaline occurrence, etc. The file permits filtering based on the data and all other attributes. Some filter options that may be useful are: “Publication”, “Deposit category”, “Country”, “Tourmaline host category”, “Tourmaline origin”, “Fluid source”, “Zoning”, “Mineralization”. It is important to note that the article linked to this database (“Application of boron isotopes in tourmaline to understanding hydrothermal ore systems” by Trumbull et al.; doi: https://doi.org/10.1016/j.oregeorev.2020.103682) discusses only tourmaline designated as “Hydrothermal” or “Hydrothermal?” in the database and reported in ISI-listed, English-language publications. This selection resulted in a total of 2622 d11B values reported in 49 publications.
Cite this dataset
Trumbull, Robert B.; Codeço, Marta S.; Jiang, Shao-Yong; Palmer, Martin R.; Slack, John F. (2020), “Boron isotopes in tourmaline from hydrothermal ore systems”, Mendeley Data, V4, doi: 10.17632/tv5y7xt9fb.4
Cite the article:
Trumbull, Robert B.; Codeço, Marta S.; Jiang, Shao-Yong; Palmer, Martin R.; Slack, John F. (2020), “Boron isotope variations in tourmaline from hydrothermal ore deposits: A review of controlling factors and insights for mineralizing systems”, Ore Geology Reviews, 125: 103682, doi: https://doi.org/10.1016/j.oregeorev.2020.103682
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Boron isotope variations in tourmaline from hydrothermal ore deposits: A review of controlling factors and insights for mineralizing systems
No full textTourmaline group minerals are typically the predominant host of boron in hydrothermal mineral deposits. Boron is a fluid-mobile element whose isotopic composition reflects many factors that are relevant to understanding mineralizing processes, including fluid source(s), fluid-rock interaction, and formational temperature. A new compilation of 2622 published δ
11B values for tourmaline from diverse types of hydrothermal ore deposits is presented here, with the focus (2215 analyses) on seven main types: porphyry Cu-Mo-Au deposits, granite-related Sn-W deposits, IOCG deposits, orogenic Au deposits, stratabound VMS and SEDEX deposits, and sediment-hosted U deposits. The total range of δ
11B values for the seven types is −26.8 to +35.0‰. Four (granite Sn-W, orogenic Au, stratabound VMS and SEDEX) have median δ
11B values close to the continental crustal average of about −10‰. The median values for IOCG and porphyry Cu-Mo-Au deposits are higher (−3.9‰ and −2.1‰, respectively), whereas sediment-hosted U deposits have distinctly high δ
11B (median = +25.3‰). Importantly, a considerable range of δ
11B values exists for tourmaline within each deposit type, the smallest (17.8‰) for granite Sn-W deposits and the largest (48.0‰) for IOCG deposits. The boron isotope variations in tourmaline from different deposits are suggested to reflect three levels of controlling factors and how these factors operated is illustrated with a selected number of case studies. The primary factor is the composition of the boron source; secondary effects relate to fluid-tourmaline fractionation (equilibrium or Rayleigh). There are commonly also tertiary factors that depend on evolution of the specific deposit. These include fluid mixing, changing water–rock ratio and/or depositional temperature, influences of other boron-bearing minerals, and where relevant, post-ore metamorphism. Separating the effects of these factors is rarely possible from boron isotopes alone. However, the growth of multi-isotope studies of tourmaline and coexisting phases such as mica, as well as developments in modelling/experimentation of boron isotopes and element partitioning, suggest that this limitation will be overcome.
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Re/Os Age Determination, Lead and Sulphur Isotope Constraints on the Origin of the Bouskour Cu–Pb–Zn Vein-Type Deposit (Eastern Anti-Atlas, Morocco) and Its Relationship to Neoproterozoic Granitic Magmatism
Full text linkThe newly re-evaluated Bouskour deposit is a large, polymetallic
vein-type system in the Precambrian Sidi Flah-Bouskour inlier of the
eastern Anti-Atlas orogen. Resources are >53 Mt at 0.8 % Cu, of which
21 Mt has a higher grade of 1.3 % Cu and 9 g/t Ag. Host rocks are
assigned to the Ediacaran Ouarzazate Group, and consist of a succession
of mafic-ultramafic to felsic igneous rocks, both intrusive and extrusive,
with ages ranging from 570 ± 5 to 557 ± 5 Ma, partly intruding
Cryogenian basalt and andesite. Among these igneous bodies, intrusive
felsic rocks are by far the most abundant lithologies, consisting of three
elongate, NW-SE-trending, calc-alkaline intrusions referred to as:
(1) Bouskour Granodiorite, (2) Bouskour Granite dated at 570 ± 5 Ma,
and (3) amphibole-bearing Bouskour Granodiorite. ...
3 successive stages of ore deposition are recognized. The earliest stage (I) is referred to as “Cu–Zn–(Fe–As–Co–Bi–Sn) stage” is followed by the main Cu–Pb–Zn sulphide stage (II), which accounts for most of the exploited sulphide ore at Bouskour. The latest stage (III) forms late fillings in calcite or quartz veins or within older stage I and II assemblages, and includes Au–Ag–Cu–(Zn–Pb) mineralization.
New 187 188 Os age dating of a single molybdenite crystal from stage II yields an age of 574.9 ± 2.4 Ma. This age coincides, within analytical uncertainty, with a SHRIMP U–Pb age on zircon from the Bouskour Granite. The age correspondence suggests a foremost role of granite-derived hydrothermal fluids in the genesis of this polymetallic vein system, consistent with sulphur and lead isotopic data. This timing of
mineralization relates to the final, post-collision extensional stage of the
Pan-African orogeny
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