scholarly journals Alpine peak pressure and tectono-metamorphic history of the Monte Rosa nappe: evidence from the cirque du Véraz, upper Ayas valley, Italy

2021 ◽  
Vol 114 (1) ◽  
Author(s):  
Joshua D. Vaughan-Hammon ◽  
Cindy Luisier ◽  
Lukas P. Baumgartner ◽  
Stefan M. Schmalholz

AbstractThe Monte Rosa nappe consists of a wide range of lithologies that record conditions associated with peak Alpine metamorphism. While peak temperature conditions inferred from previous studies largely agree, variable peak pressures have been estimated for the Alpine high-pressure metamorphic event. Small volumes of whiteschist lithologies with the assemblage chloritoid + phengite + talc + quartz record peak pressures up to 0.6 GPa higher compared to associated metapelitic and metagranitic lithologies, which yield a peak pressure of ca. 1.6 GPa. The reason for this pressure difference is disputed, and proposed explanations include tectonic mixing of rocks from different burial depths (mélange) or local deviations of the pressure from the lithostatic value caused by heterogeneous stress conditions between rocks of contrasting mechanical properties. We present results of detailed field mapping, structural analysis and a new geological map for a part of the Monte Rosa nappe exposed at the cirque du Véraz field area (head of the Ayas valley, Italy). Results of the geological mapping and structural analysis shows the structural coherency within the western portions of the Monte Rosa nappe. This structural coherency falsifies the hypothesis of a tectonic mélange as reason for peak pressure variations. Structural analysis indicates two major Alpine deformation events, in agreement with earlier studies: (1) north-directed nappe emplacement, and (2) south-directed backfolding. We also analyze a newly discovered whiteschist body, which is located at the intrusive contact between Monte Rosa metagranite and surrounding metapelites. This location is different to previous whiteschist occurrences, which were entirely embedded within metagranite. Thermodynamic calculations using metamorphic assemblage diagrams resulted in 2.1 ± 0.2 GPa and 560 ± 20 °C for peak Alpine metamorphic conditions. These results agree with metamorphic conditions inferred for previously investigated nearby whiteschist outcrops embedded in metagranite. The new results, hence, confirm the peak pressure differences between whiteschists and the metagranite and metapelite. To better constrain the prograde pressure–temperature history of the whiteschist, we compare measured Mg zoning in chloritoid with Mg zoning predicted by fractional crystallization pseudo-section modelling for several hypothetical pressure–temperature paths. In order to reach a ca. 0.6 GPa higher peak pressure compared to the metapelite and metagranite, our results suggest that the whiteschist likely deviated from the prograde burial path recorded in metapelite and metagranite lithologies. However, the exact conditions at which the whiteschist pressure deviated are still contentious due to the strong temperature dependency of Mg partitioning in whiteschist assemblages. Our pseudo-section results suggest at least that there was no dramatic isothermal pressure increase recorded in the whiteschist.

2021 ◽  
Author(s):  
Maria Di Rosa

In this work the central area of Corsica island was studied in order to reconstruct the tectono-metamorphic history of the continental and oceanic high pressure units that occupy the structurally deeper levels of the tectonic stacking of Alpine Corsica and their stratigraphic and structural relationship with the European margin (Hercynian Corsica). The study includes the geological mapping, the mesoscale and microscale structural analysis, the acquisition of chemical analyzes and micromaps with the microprobe, thermobarometric estimation through specific methodologies for metapelites, U-Th-Pb dating of zircons and allanites. The results obtained allows to reconstruct the geodynamic model of this sector of the Alpine belt from the Permian to the Burdigalian.


1984 ◽  
Vol 121 (4) ◽  
pp. 339-345 ◽  
Author(s):  
Eileen McLellan

AbstractAn understanding of the response of migmatites to deformation is crucial to an interpretation of their structures, and in anatectic and intrusive migmatite terrains due consideration must be given to the modification of deformation processes imposed by melts. In partially molten systems containing more than 30% melt the classical theories of fold formation are inapplicable; the folds produced are of the ‘viscous fold’ type. Their geometry is unpredictable and may mimic structures due to refolding; this is particularly true at very high degrees of melting where flow of melt carrying rafts of solids begins. Failure to distinguish ‘viscous folds’ from the products of refolding will lead to errors in interpreting the structural and metamorphic history of an area, and to consequent misinterpretation of the true structural relations between geometrically complex high-grade and more regularly deformed low-grade areas.


1984 ◽  
Vol 21 (7) ◽  
pp. 853-863 ◽  
Author(s):  
A. Indares ◽  
J. Martignole

Pelitic and basic rocks of the Grenville Supergroup in the Maniwaki area (100 km north of Ottawa) were selected for a detailed investigation of the metamorphic history of the Central Metasedimentary Belt of the Grenville Province.Mineral assemblages suggest metamorphic conditions of the granulite facies with local and irregular persistence of the amphibolite facies. Chemical analysis of minerals reveals a lack of equilibrium on the thin section scale. Systematic variation of mineral compositions is explained as the net result of several mineral equilibria established at different stages during the metamorphic evolution of the area. Peak temperatures obtained by biotite–garnet thermometry (cores of isolated grains) are between 760 and 860 °C, whereas clinopyroxene–garnet thermometry gives 740–820 °C. Retrograde temperatures as estimated by various thermometers range between 550 and 750 °C (biotite–garnet), 498 and 670 °C (cordierite–garnet), and 690 and 720 °C (clinopyroxene–garnet). Peak pressures were 6.5–8.5 kbar (650–850 MPa) based upon the ga–pl–sil–qtz barometer and the cpx–ga–pl–qtz barometer. Retrograde pressures of 3.5–5.5 kbar (350–550 MPa) (ga–pl–sil–qtz), 4.1–5.2 kbar (410–520 MPa) (cd–ga), and 5.7–7 kbar (570–700 MPa) (cpx–ga–pl–qtz) were determined.A compilation of results in a P–T diagram allows us to construct a retrograde gradient convex towards the T axis, with an average slope of 12 bar/°C (1.2 MPa/°C). This curve suggests fast uplift and erosion just after the peak of metamorphism followed by a long cooling stage accompanied by minor uplift.


2019 ◽  
Vol 62 (12) ◽  
pp. 4335-4350 ◽  
Author(s):  
Seth E. Tichenor ◽  
J. Scott Yaruss

Purpose This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings. Method In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences. Results Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states. Conclusion Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.


2018 ◽  
Vol 7 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Erin Sullivan ◽  
Marie Louise Herzfeld-Schild

This introduction surveys the rise of the history of emotions as a field and the role of the arts in such developments. Reflecting on the foundational role of the arts in the early emotion-oriented histories of Johan Huizinga and Jacob Burkhardt, as well as the concerns about methodological impressionism that have sometimes arisen in response to such studies, the introduction considers how intensive engagements with the arts can open up new insights into past emotions while still being historically and theoretically rigorous. Drawing on a wide range of emotionally charged art works from different times and places—including the novels of Carson McCullers and Harriet Beecher-Stowe, the private poetry of neo-Confucian Chinese civil servants, the photojournalism of twentieth-century war correspondents, and music from Igor Stravinsky to the Beatles—the introduction proposes five ways in which art in all its forms contributes to emotional life and consequently to emotional histories: first, by incubating deep emotional experiences that contribute to formations of identity; second, by acting as a place for the expression of private or deviant emotions; third, by functioning as a barometer of wider cultural and attitudinal change; fourth, by serving as an engine of momentous historical change; and fifth, by working as a tool for emotional connection across communities, both within specific time periods but also across them. The introduction finishes by outlining how the special issue's five articles and review section address each of these categories, while also illustrating new methodological possibilities for the field.


2020 ◽  
Vol 48 (3-4) ◽  
pp. 13-26
Author(s):  
Brandon W. Hawk

Literature written in England between about 500 and 1100 CE attests to a wide range of traditions, although it is clear that Christian sources were the most influential. Biblical apocrypha feature prominently across this corpus of literature, as early English authors clearly relied on a range of extra-biblical texts and traditions related to works under the umbrella of what have been called “Old Testament Pseudepigrapha” and “New Testament/Christian Apocrypha." While scholars of pseudepigrapha and apocrypha have long trained their eyes upon literature from the first few centuries of early Judaism and early Christianity, the medieval period has much to offer. This article presents a survey of significant developments and key threads in the history of scholarship on apocrypha in early medieval England. My purpose is not to offer a comprehensive bibliography, but to highlight major studies that have focused on the transmission of specific apocrypha, contributed to knowledge about medieval uses of apocrypha, and shaped the field from the nineteenth century up to the present. Bringing together major publications on the subject presents a striking picture of the state of the field as well as future directions.


2019 ◽  
Vol 20 (2) ◽  
pp. 49-54
Author(s):  
Dildora Alinazarova ◽  

In this article, based on an analysis of a wide range of sources, discusses the emergence and development of periodicals and printing house in Namangan. The activities of Ibrat- as the founder of the first printing house in Namangan are considered. In addition, it describes the functioning and development of "Matbaai Ishokia" in the past and present


2019 ◽  
Vol 14 (1-2) ◽  
pp. 295-297
Author(s):  
Sergej A. Borisov

For more than twenty years, the Institute of Slavic Studies of the Russian Academy of Sciences celebrates the Day of Slavic Writing and Culture with a traditional scholarly conference.”. Since 2014, it has been held in the young scholars’ format. In 2019, participants from Moscow, St. Petersburg, Kazan, Togliatti, Tyumen, Yekaterinburg, and Rostov-on-Don, as well as Slovakia, the Czech Republic, Hungary, and Romania continued this tradition. A wide range of problems related to the history of the Slavic peoples from the Middle Ages to the present time in the national, regional and international context were discussed again. Participants talked about the typology of Slavic languages and dialects, linguo-geography, socio- and ethnolinguistics, analyzed formation, development, current state, and prospects of Slavic literatures, etc.


Author(s):  
O. Y. Balalaieva ◽  

The purpose of the article is to study the dynamics of electronic dictionaries development abroad and in Ukraine using methods of analysis of scientific sources, comparison, generalization and systematization. Electronic dictionaries have been found to be a relatively new phenomenon in the lexicographic market, evolving from machine-readable dictionaries, exact copies of paper editions to complex digital lexicographic systems with a powerful arsenal of functions over the decades. The stages of development of autonomous and online dictionaries are described. Electronic dictionaries due to the advanced search capabilities, speed, simplicity, ease of use, accessibility and compactness have gained popularity among a wide range of users. Today they are used in many spheres of human activity – scientific, educational, professional, everyday communication. However, the analysis of the current level of development of Ukrainian electronic resources indicates a shortage of electronic dictionaries both common and terminological vocabulary. The lack of electronic dictionaries is due to a number of objective problems, both practical and theoretical, that is why research in the field of domestic computer lexicography is a promising area of further research.


2020 ◽  
Vol 26 (6) ◽  
pp. 613-618
Author(s):  
A. V. Altukhov ◽  
S. A. Tishchenko

The presented study reviews practically relevant research papers in the field of network structures, modern network business models and platforms.Aim. The study aims to elaborate and explain the concept of network structure and platform and to show the reasons for the progressiveness and potential of network organizational structure at the current stage of socio-economic and scientific development.Tasks. The authors highlight the main scientific ideas about network structures in business, including significant studies in this area; provide and explain the main terms and definitions and examine the key characteristics of network business structures; characterize “platforms” as an important concept for modern business and show the relationship between platforms and network structures.Methods. This study uses analysis of information and subsequent synthesis of new knowledge in the form of the authors’ conclusions and a wide range of relevant scientific publications of Russian and foreign authors, including original publications in English and French.Results. The history of network structures is briefly provided. Definitions and characteristics of such concepts as “network structure” and “platform” in relation to business are provided and explained by the authors.


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