1,720,973 research outputs found
The Oligocene Reifnitz tonalite (Austria) and its host rocks: implications for Cretaceous and Oligocene–Neogene tectonics of the south-eastern Eastern Alps
No full textAbstract
In the south-eastern Eastern Alps, the Reifnitz tonalite intruded into the Austroalpine metamorphic basement of the Wörthersee half-window exposed north of the Sarmatian–Pliocene flexural Klagenfurt basin. The Reifnitz tonalite is dated for the first time, and yields a laser ICP-MS U–Pb zircon age of 30.72±0.30 Ma. The (U–Th–Sm)/He apatite age of the tonalite is 27.6 ± 1.8 Ma implying rapid Late Oligocene cooling of the tonalite to ca. 60 °C. The Reifnitz tonalite intruded into a retrogressed amphibolite-grade metamorphic basement with a metamorphic overprint of Cretaceous age (40Ar/39Ar white mica plateau age of 90.7 ± 1.6 Ma). This fact indicates that pervasive Alpine metamorphism of Cretaceous age extends southwards almost up to the Periadriatic fault. Based on the exhumation and erosion history of the Reifnitz tonalite and the hosting Wörthersee half window formed by the Wörthersee anticline, the age of gentle folding of Austroalpine units in the south-eastern part of the Eastern Alps is likely of Oligocene age. North of the Wörthersee antiform, Upper Cretaceous–Eocene, Oligocene and Miocene sedimentary rocks of the Krappfeld basin are preserved in a gentle synform, suggesting that the top of the Krappfeld basin has always been near the Earth’s surface since the Late Cretaceous. The new data imply, therefore, that the Reifnitz tonalite is part of a post-30 Ma antiform, which was likely exhumed, uplifted and eroded in two steps. In the first step, which is dated to ca. 31–27 Ma, rapid cooling to ca. 60 °C and exhumation occurred in an E–W trending antiform, which formed as a result of a regional N–S compression. In the second step of the Sarmatian–Pliocene age a final exhumation occurred in the peripheral bulge in response to the lithospheric flexure in front of the overriding North Karawanken thrust sheet. The Klagenfurt basin developed as a flexural basin at the northern front of the North Karawanken, which represent a transpressive thrust sheet of a positive flower structure related to the final activity along the Periadriatic fault. In the Eastern Alps, on a large scale, the distribution of Periadriatic plutons and volcanics seems to monitor a northward or eastward shift of magmatic activity, with the main phase of intrusions ca. 30 Ma at the fault itself.</jats:p
Electron microprobe analysis of polyhalite from the evaporitic Permian Haselgebirge Formation
No full textElectron microprobe analyses were conducted at the University of Salzburg, Department of Geography and Geology, in the year 2011. Measurements were performed on a JEOL electron microprobe (JXA-8600), equipped with a wave-length dispersive system. An acceleration voltage of 15 kV and a low sample current of 20 nA were applied to prevent decomposition of polyhalite under the electron beam. Additionally, the spot was defocused to a diameter of 15 µm and after measurement of sulfur, the sample was moved one beam diameter to start measurement of potassium and calcium. Sulfur, potassium and calcium were all measured with the same analyzing crystal. Synthetic and natural mineral standards were used to analyse the emitted wave lengths of the sample and to quantify their amount. Standard ZAF correction calculation revealed the composition in oxide weight percent. The calculation method after Love/Scott1 revealed the formula units of polyhalite (doi:10.1594/PANGAEA.942485)
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
Formula units of polyhalite from the evaporitic Permian Haselgebirge Formation
No full textElectron microprobe analyses were conducted at the University of Salzburg, Department of Geography and Geology, in the year 2011. Measurements were performed on a JEOL electron microprobe (JXA-8600), equipped with a wave-length dispersive system. An acceleration voltage of 15 kV and a low sample current of 20 nA were applied to prevent decomposition of polyhalite under the electron beam. Additionally, the spot was defocused to a diameter of 15 µm and after measurement of sulfur, the sample was moved one beam diameter to start measurement of potassium and calcium. Sulfur, potassium and calcium were all measured with the same analyzing crystal. Synthetic and natural mineral standards were used to analyse the emitted wave lengths of the sample and to quantify their amount. Standard ZAF correction calculation revealed the composition in oxide weight percent (doi:10.1594/PANGAEA.942486). The calculation method after Love/Scott1 revealed the formula units of polyhalite
Electron microprobe analysis and Ar-Ar age dating of polyhalite from the evaporitic Permian Haselgebirge Formation
No full textTo test polyhalite age dating of the mineral polyhalite [K2Ca2Mg(SO4)4·2H2O], samples of the evaporitic Permian Haselgebirge Formation were collected in the Eastern Alps. Samples were taken from two salt bodies. The salt body of Altaussee (UTM 33T 405316 5278325) has a vertical thickness of >800 m. Samples were collected in the Altaussee mine (ALT). The salt body of Bad Dürrnberg-Berchtesgaden (UTM 33T 351091 5278007) is at least 1000 m thick. The salt body comprises two separate mines, where samples were collected, Bad Dürrnberg (DÜ) and Berchtesgaden (BGD) salt mines. The samples were collected during several field trips, and investigated at the University of Salzburg during the years 2007-2015. Electron microprobe analyses were conducted to determine possible chemical variations of polyhalite
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
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