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Miocene structural inversion of the Paleogene Adjara-Trialeti back-arc basin (SW Georgia, Caucasus) in the context of the Arabia-Eurasia collision zone
No full textYoung back-arc rift basins, because of the not yet dissipated extensional thermal signature, are prone to positive inversion following changes in the local geodynamic regime and/or far-Xeld stress transmission. Structural inversion of such basins tends to exploit and reactivate the former normal faults, particularly if the latter are favourably oriented with respect to the direction of stress transfer. The Adjara-Trialeti fold-and-thrust belt (ATFTB) of SW Georgia perfectly exempliXes this mechanism: it results from the structural inversion of a continental back-arc rift basin developed on the upper plate of the northern Neotethys slab in Paleogene times, behind the long-lived Pontides-Lesser Caucasus magmatic arc. Integration of (i) thermal maturity analyses on the former sedimentary Xll of the Adjara- Trialeti back-arc basin and (ii) low-temperature thermochronological [apatite Xssion-track (AFT) and (U-Th)/He (AHe)] analyses on both the former sedimentary Xll and syn-rift plutons provides constraints on the burial-exhumation history of the ATFTB. Maximum paleotemperatures reached by the oldest (Paleocene) rocks within the former Adjara- Trialeti basin are in the order of about 110-115°C. AFT central ages range between 46 and 15 Ma, while AHe ages cluster mainly between 10 and 3 Ma. The reconstructed maximum paleotemperatures indicate that AFT ages are only partially reset, whereas AHe ages are totally reset. Thermal modelling, integrating AFT and AHe data with independent geological constraints, clearly indicates that the Adjara-Trialeti back-arc basin was inverted starting from the Middle Miocene. This result is corroborated by several independent geological evidence, available for example in the adjacent Rioni, Kartli and Kura foreland basins and in the eastern Black Sea offshore, which all suggest a Middle-Late Miocene phase of deformation linked with the ATFTB building. Adjara-Trialeti structural inversion can be correlated with the widespread Middle-to-Late Miocene phase of shortening and exhumation registered from the eastern Pontides to the Lesser Caucasus, the Talysh and the Alborz ranges. This tectonic phase can in turn be interpreted as a far-Xeld effect of the Arabia-Eurasia collision, developed coevally along the Bitlis-Zagros suture hundreds of kilometres to the south
Using multi-proxy thermal maturity datasets to validate deformation styles from the Adjara-Trialeti fold-and-thrust belt to the Greater Caucasus (Georgia)
No full textWe present a brand new multi-proxy dataset of thermal maturity indicators, which derive from the application of several analytical techniques on surface and subsurface sedimentary successions. The study area spans from the Greater Caucasus to the Adjara-Trialeti fold-and-thrust belt (FTB), comprising the intervening western Kura Basin, in Georgia, and represents a region of continental deformation in the hinterland of the Arabia-Eurasia collision zone. Original and published clay mineralogy, Raman spectroscopy and petrography on dispersed organic matter, and pyrolysis data are integrated for the first time in a coherent tectono-sedimentary scenario. Thermal maturity spans from the low diagenetic realm (60-80°C) in the Upper Miocene section of the Kura sedimentary fill, to the oil window in the Cretaceous to Lower Miocene successions of Adjara-Trialeti FTB, Kakheti ridge and Kura Basin (70-120°C), up to about 400°C in the Greater Caucasus core. Integration of different indicators, besides allowing the estimation of maximum burial temperatures acquired through time, enabled to draw the tectonic evolution of the area. Different maturity trends and thermal histories, coupled with structural and stratigraphic data, highlight that the study area comprises two domains derived from positive tectonic inversion: the E-W Adjara-Trialeti doubly-verging FTB from an Eocene back-arc rift basin and the SSW-verging Georgian Greater Caucasus from a Mesozoic rift basin. Between the two, thin-skinned south-verging thrusts deform the Kura Basin and the Kakheti ridge successions, originally deposited on an extensional structural high which was later flexured during compression. The similar thermal maturity degree in the Adjara-Trialeti FTB and the
Kakheti ridge/Kura Basin areas has been acquired in different time spans: during Paleogene extension and during Miocene thin-skinned shortening, respectively. The results indicate that thermal maturation of the sedimentary successions in the Adjara-Trialeti FTB can be ascribed to burial during rift evolution. The same conclusion can be drawn for the axial zone of the Greater Caucasus, whereas tectonic overburden may have contributed to the thermal maturity of the rocks in the southern foothills of the Greater Caucasus: this area needs further work to assess its tectonic evolution
Validating far-field deformation styles from the Adjara-Trialeti fold-and-thrust belt to the Greater Caucasus (Georgia) through multi-proxy thermal maturity datasets
Get PDFThermal history reconstructions can help to better characterise the geological history of areas that experienced a polyphase tectonic evolution. The integration of published stratigraphic/structural data with new and pre- existing data on thermal maturity (clay mineralogy, Raman spectroscopy, vitrinite reflectance, and pyrolysis) of both surface and subsurface sedimentary successions of a wide region of Georgia including -north to south- the southern Greater Caucasus, the western Kura Basin, and the Adjara-Trialeti fold-and-thrust belt (FTB) provides cogent constraints on its late Mesozoic-Cenozoic tectono-sedimentary evolution.
Overall, thermal maturity spans from the low diagenesis (60–80 ◦C) in the Upper Miocene section of the Kura Basin to anchizone-epizone (about 400 ◦C) in the central Greater Caucasus axial zone. In more detail, different maturity trends and thermal histories point to the existence of two domains formed by positive tectonic inver- sion: (i) the Adjara-Trialeti FTB from an Eocene rift basin and (ii) the Greater Caucasus from a Mesozoic rift basin. Multiple thermal indicators, along with stratigraphic/structural evidence, show that the Paleocene section of the Adjara-Trialeti basin fill reached the upper oil window (ca. 115 ◦C) during maximum sedimentary burial and that the whole basin was then exhumed starting from the late Middle Miocene. A positive correlation be- tween thermal maturity and stratigraphic age points to a limited thermal effect of tectonic loading. In the southern Greater Caucasus, thermal maturity increases progressively with stratigraphic age, from ca. 100 ◦C (Upper Eocene) to 400 ◦C (Lower Jurassic), in broad agreement with the reconstructed thickness of the basin-fill succession, thus indicating that most of the thermal maturity was again induced by sedimentary burial.
As to the flexural western Kura Basin, its Maikopian (Oligocene-Early Miocene) section reached the oil window (up to ca. 110 ◦C) whereas the Middle-Late Miocene one is immature. The Kakheti ridge -a highly tectonised portion of the Kura Basin- reached immature to early mature conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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