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1
Monier, Gilles, e Jean-Louis Robert. "Muscovite solid solutions in the system K2O-MgO-FeO-Al2O3-SiO2-H2O: an experimental study at 2 kbar PH2O and comparison with natural Li-Free white micas". Mineralogical Magazine 50, n. 356 (giugno 1986): 257–66. http://dx.doi.org/10.1180/minmag.1986.050.356.08.
Testo completoAbstract (sommario):
AbstractThis paper presents the results of an experimental study of muscovite solid solutions in the system K2O-M2+O-Al2O3-SiO2-H2O-(HF), with M2+ = Mg2+ or Fe2+ in the temperature range 300-700°C under 2 kbar PH2O. Muscovite solid solutions can be described, in this system, as the result of two substitutions. One is the phengitic substitution (x), which preserves the pure dioctahedral character of the mica; the second is the biotitic substitution (y), which leads to trioctahedral micas and does not change the composition of the tetrahedral layer Si3Al. The general formula of muscovite in this system is K(Al2−x−2y∕3M2+x+y□1−y∕3)(Si3+xAl1−x)O10(OH,F)2. Both substitutions x and y are more extensive at lower temperatures. The extent of solid solution decreases drastically with increasing temperature.For T > 600°C, the phengitic substitution (x) becomes negligible, but some biotitic substitution (y) persists. This unsymmetrical decrease of the solid solution of muscovite with increasing temperature is similar to that previously observed in phlogopite, the micas with a tetrahedral layer composition of Si3Al being the most stable. The behaviour of muscovite solid solutions in the ferrous system is qualitatively identical to that observed in the magnesian one, but the extent of solid solution is smaller than with Mg2+. Fluorine neither changes the size nor the shape of the solid solution fields but increases their stability by about 50°C.A comparison of these experimental results with data on natural muscovites is presented. Most natural primary (magmatic) granitic muscovites lie very close to the muscovite end member, in agreement with their high-temperature origin. Low-temperature muscovites (300–400°C), typically muscovites from hydrothermally altered granitic rocks, can have high x and y values. The rate of the biotitic substitution y can reach 0.6, which corresponds to an octahedral occupancy of 2.2 atoms per formula unit (based on 11 oxygens), consistent with the experimental data.
2
Peruzzo, Luca, Raffaele Sassi e F. P. Sassi. "Sulla vanabilità compositiva delle miche nell’amhito di uno stesso affioramento di metapeliti di basso grado: un esempio. 2: Le muscoviti e considerazioni conclusive". Rendiconti Lincei 3, n. 1 (marzo 1992): 43–55. http://dx.doi.org/10.1007/bf03002963.
Testo completo
3
Dallmeyer, R. D., J. D. Keppie e R. D. Nance. "40Ar/39Ar ages of detrital muscovite within Lower Cambrian and Carboniferous clastic sequences in northern Nova Scotia and southern New Brunswick: implications for provenance regions". Canadian Journal of Earth Sciences 34, n. 2 (1 febbraio 1997): 156–68. http://dx.doi.org/10.1139/e17-013.
Testo completoAbstract (sommario):
Detrital muscovite from lowermost Cambrian sequences exposed in the Avalon Composite Terrane in Nova Scotia and New Brunswick record 40Ar/39Ar plateau ages of ca. 625–600 Ma. These are interpreted to date times of cooling in source areas. The regional distribution of coarse-grained detrital muscovite in Lower Cambrian rocks of Avalonian overstep sequences suggests a source region of dimensions considerably larger than any presently exposed in Appalachian segments of the Avalon Composite Terrane. Late Proterozoic tectonic reconstructions locate the Avalon Composite Terrane adjacent to northwestern South America, thereby suggesting a possible source within Late Proterozoic PanAfrican – Brasiliano orogens. Detrital muscovite from clastic sequences of the proximally derived, Lower Carboniferous (Tournaisian) Horton Group and the more distal Upper Carboniferous (Westphalian D – Stephanian) Pictou Group in Nova Scotia records 40Ar/39Ar spectra that define plateau ages of ca. 390–380 Ma (Horton Group) and and ca. 370 Ma (Pictou Group). Finer grained fractions from samples of the Horton Group display more internally discordant age spectra defining total-gas ages of ca. 397–395 Ma. A provenance for the finer muscovite may be found in southern Nova Scotia where Cambrian–Ordovician turbidites of the Meguma Group display a regionally developed micaceous cleavage of this age. The ca. 390–380 Ma detrital muscovites probably were derived from granite stocks presently exposed in proximal areas of northernmost Cape Breton Island. A more distal source for the ca. 370 Ma detrital muscovites in the Pictou Group is suggested by its original extensive distribution, although a local, possibly recycled, source may also have been present. The presence of only 400–370 Ma detrital muscovite suggests a rapidly exhumed orogenic source with characteristics similar to those of crystalline rocks presently exposed in the Cape Breton Highlands and (or) the Meguma Terrane.
4
Treloar, Peter J. "Chromian muscovites and epidotes from Outokumpu, Finland". Mineralogical Magazine 51, n. 362 (ottobre 1987): 593–99. http://dx.doi.org/10.1180/minmag.1987.051.362.14.
Testo completoAbstract (sommario):
AbstractThe Outokumpu region of Finland is notable for the large number of Cr-rich silicate and oxide phases associated with the massive sulphide deposits. In this paper analyses of Cr-rich phases in the epidote-clinozoisite and muscovite groups are presented. The muscovite-type phase shows a maximum 80% substitution of Cr for A1 on octahedral sites with a maximum 24.7 wt.% Cr2O3. Apparent complete solid solution between this extreme composition and the fuchsitic muscovites is indicated. The clinozoisite type phase has a maximum 15.4 wt.% Cr2O3, with a composition close to Ca2CrAl2Si3O12(OH). As with the micas, complete solid solution of Cr for Al in the clinozoisite structure is indicated.
5
Pereira, Ronaldo Mello, Diana Rodrigues, Ciro Alexandre Ávila e Reiner Neumann. "Stockscheider Quartzo-Moscovíticos e Pegmatíticos na Zona de Cúpula do Granitóide Ritápolis, Região de São João del Rei, Minas Gerais". Anuário do Instituto de Geociências 34, n. 2 (1 gennaio 2011): 59–69. http://dx.doi.org/10.11137/2011_2_59-69.
Testo completoAbstract (sommario):
Clusters of essentially quartz-muscovitic rocks were found in four areas of the São João del Rei Pegmatite Province in close association with pegmatites positioned parallel to the contact between the Ritápolis granitoid and the metavolcanic - metasedimentary rocks of the Rio das Mortes greenstone belt. The suite of accessory minerals associated to the quartz-muscovite and pegmatite stockscheider (columbite-tantalite, cassiterite, gahnite, zircon, xenotime and monazite) are similar to those determined for the pegmatites of the province. The mineralogy of inclusions (Pb-tantalite, microlite, Pb-microlite, U-microlite, Ba-microlite, Hf-rich zircon) in the Fe-columbite associated to the stockscheider is similar to those determined for the Fe-columbite of the more evolved pegmatites found in the province. The quartz-muscovite and pegmatite stockscheider are related to Ritápolis granitoid with is related to the other pegmatites of São João del Rei Pegmatite Province. The proposed mechanism for the formation of clusters of muscovite-quartz and pegmatitic stockscheider is the crystallization of pockets of tardi-magmatic and pos-magmatic hydrothermal - metasomatic fluids segregated from the parental granitic magma and injected into fractures parallel to the roof contact of the granitoid dome.
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Halperin, Charles J. "“Scratch a Russian, Find a Turk”". Russian History 45, n. 4 (27 novembre 2018): 367–77. http://dx.doi.org/10.1163/18763316-04504004.
Testo completoAbstract (sommario):
In this first-rate monograph, Cornelia Soldat confirms earlier impressionistic assertions that the portrayal of Ivan iv as a tyrant and the Muscovites as barbarians in German-language pamphlets (Flugschriften) written as propaganda during the Livonian War (1558–1582), are simply projections onto the Muscovite discourse of the motifs of the anti-Ottoman discourse that originated in the fifteenth century after the fall of Constantinople in 1453. Therefore the pamphlets have no value whatsoever for the study of sixteenth- and seventeenth-century Muscovite history. These conclusions have wider significance for the interpretation of the historical reliability of two other source genres beyond the scope of Soldat’s monograph, Livonian chronicles and defector German travel accounts written by Germans who served Ivan iv but then fled Muscovy to write scurrilous denunciations of him as a tyrant.
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Brown, Peter B. "Muscovite Arithmetic in Seventeenth-Century Russian Civilization: Is It Not Time to Discard the “Backwardness” Label?" Russian History 39, n. 4 (2012): 393–459. http://dx.doi.org/10.1163/48763316-03904001.
Testo completoAbstract (sommario):
Muscovite civilization utilized Byzantine-Greek alphanumerals for its mathematical symbols. Occasionally derided by historians for being retrograde in comparison to the Hindu-Arabic numerals sixteenth- and seventeenth-century Europe adopted, Muscovy’s alphanumerals were versatile and suitably contoured to perform a variety of computational tasks. Muscovite alphanumerals were an integral part of early Moderen Russia’s administrative culture, and played a prominent role in fostering the experiential knowledge underlying the educational achievements of the Imperial Period. Though they lacked the zero and the decimal, Muscovites still had a reasonable grasp of the base-ten system, and comprehended well basic arithmetical skills and relationship properties, less so equational ones. The Russians developed complex abaci well suited for commercial transactions, large-scale construction, military inventories and payrolls, and the land registry, to name a few. These instruments manipulated an extensive variety of weights, measures, linear distances, area dimensions, volume measurements, and currency. Muscovite arithmetic was a prominent factor assisting in the advancement of critical thinking skills in 1600’s Russia. Nonetheless, as the seventeenth century wore on, sociological, educational or pedagogical, military scientific, administrative, and cultural arguments or interactive phenomena came to bear and increasingly found the Muscovite algorithmic symbols wanting. In 1699 the government decreed that Hindu-Arabic numerals henceforth were to be used in official documents throughout the country. Directly and indirectly, the complex thought processes bound up when operating with Muscovite alphanumerals were one impetus for the further unfolding of Russian civilization after 1700.
8
Ružička, Peter, Pavol Myšľan e Sergii Kurylo. "Minerálne zloženie metapelitovej a metapyroklastickej zložky kryštalických vápencov z lokalít Lubeník a Ochtiná (Slovenská republika)". Bulletin Mineralogie Petrologie 28, n. 2 (2020): 281–89. http://dx.doi.org/10.46861/bmp.28.281.
Testo completoAbstract (sommario):
Crystalline limestones from the localities Lubeník and Ochtiná (Slovak Republic) have been formed by recrystallization of limestones enriched by basaltic tuffogenic material and a minor pelitic component. The regional metamorphism and tectonic activity associated with Alpine orogennesis resulted in origin of various color and textural varieties of crystalline limestones. The recrystallized tuffogene-pelitic material was transformed into the laminar arrangement in crystalline limestones. The original clay-like pelitic component has probably been entirely recrystallized into muscovite. Higher contents of Fe (0.286 - 0.302 apfu) and Mg (0.342 - 0.396 apfu) are present in muscovites from Lubeník compared to those from Ochtiná. Recrystallized tuffogenic material is represented by epidote, titanite, magnetite and fluorapatite inclusions in muscovites. Quartz and albite form part of a calcite matrix in the crystalline limestones.
9
Selin, Adrian Aleksandrovich. "«Expelled from Livonia»: Towards the issue of the arrangement of landowners of «Old» and «New German towns» after the Plyussa Treaty 1583". Studia Slavica et Balcanica Petropolitana, n. 2 (28) (2020): 24–35. http://dx.doi.org/10.21638/spbu19.2020.202.
Testo completoAbstract (sommario):
History of Muscovite estate shaping in “German towns” in 1550s–1580s is closely connected with Novgorod, Pskov, Rzheva Pustaya as servicemen communities. These servicemen were the source for new landowners in the lands taken by Muscovites to the West from Narova river. Only Rzheva Pustaya was more or less studied already. The paper is an attempt to generalize the data on number and personal content of “German towns” landowners (mostly on sources of 1582) and to study the issue of the significance of the experience of making estates in Livonian lands for the day-to-day culture of Muscovite servicemen. Geography of Russian landownership in Livonia is under consideration. Also the historiographical discussions of the reasons of Russian Livonia project fail is studied in the article. Special attention is paid to the issue of Muscovite landowners evacuation from Livonia after military defeats of 1580–1582. Record books of Rzheva Pustaya and Novgorod Vodskaya pyatina included notes of the towns and districts in Livonia that have been left by the landowners. Other record books of North-Western Muscovy only mention the new strata of servicemen “new landowners of German towns”. Special groups of “Rugodiv and Juryev newly baptized [tartars]” and “Cossacks from Govye” were also separately mentioned in the record books. In the last period of Livonian War not only Livonia itself but also some border districts of former Novgorod land were left by Muscovites. In 1582–1583 the Moscow Government also took responsibility for the landowners from that lost districts. V. A. Arakcheev noted the order on the land security of those servicemen issued between January 23 and March 4, 1583. In early 1580s the landowners of “German towns” received estates in “abandoned lands”. Later Court lands were spread between them.
10
Halperin, Charles J. "Ivan IV and the Tatars". Golden Horde Review 9, n. 1 (29 marzo 2021): 188–200. http://dx.doi.org/10.22378/2313-6197.2021-9-1.188-200.
Testo completoAbstract (sommario):
Research objectives: To provide a comprehensive overview of Muscovite interaction with Tatars during Ivan IV’s reign, both with each successor state of the Jochid ulus and with Tatars who moved to Muscovy and entered Ivan IV’s service. Research materials: This study is based upon Russian sources from the reign of Ivan IV concerning the Tatars, including narratives such as chronicles and documentary evidence such as diplomatic reports. Results and novelty of the research: Muscovite policy toward the Tatars did not derive from a single dominating motive, neither hostility, such as religious animosity toward Muslims or the drive for imperial territorial expansion, nor the desire to cooperate with Tatars for the sake of commerce or the need for steppe military allies. Ivan adapted his policies to individual circumstances, vassal puppet rulers or outright conquest as needed. Tatars from the vassal khanate of Kasimov helped Ivan conquer Kazan’ and Astrakhan’ and fight Crimea. Nogai merchants sold the Muscovite army horses. Muscovites possessed intimate knowledge of foreign Tatars, but also lived in close proximity to “native” Tatars who lived on Muscovite soil or traveled to Moscow as envoys or merchants. However expertise on the Tatars, borrowing Tatar institutions, enrolling Tatar servitors, and conquering successor states of the Golden Horde did not make Muscovy a successor state of the Golden Horde. Nevertheless the Tatars were a fact of life in Ivan IV’s Muscovy, as both allies and enemies.
11
Lahana, Martha. "The Usefulness of Bees in Muscovy". Russian History 45, n. 1 (3 maggio 2018): 29–51. http://dx.doi.org/10.1163/18763316-04501002.
Testo completoAbstract (sommario):
The term “bee culture” indicates the whole range of a society’s relationship to bees and their products. In Muscovite Russia bee culture is reflected in records of property ownership and management, taxation and rents, international and domestic trade, diplomacy and foreign affairs, and even food, drink, and medical care. Political centralization, economic developments, changing tastes and persistent traditions, all were reflected in bee culture. The relationship between Muscovites and their bees evolved with developments in both local and international societies, and a study of these can illuminate both.
12
Reynolds, Peter H., Georgia Pe-Piper e David J. W. Piper. "Sediment sources and dispersion as revealed by single-grain 40Ar/39Ar ages of detrital muscovite from Carboniferous and Cretaceous rocks in mainland Nova ScotiaGeological Survey of Canada contribution 20090289." Canadian Journal of Earth Sciences 47, n. 7 (luglio 2010): 957–70. http://dx.doi.org/10.1139/e10-027.
Testo completoAbstract (sommario):
Single-grain ages of detrital muscovite from 15 sand(stone) samples from the Lower Carboniferous Horton Group and the Lower Cretaceous Chaswood Formation of central Nova Scotia were used to infer the nature of the Early Carboniferous unroofing of the Meguma terrane and the reworking of Carboniferous rocks in the Early Cretaceous. In the western Windsor Basin, a sample from the oldest Horton Group rocks yielded ages principally between ca. 400 and 380 Ma, suggesting that most of the muscovite present came from the metamorphic rocks of the Meguma terrane but was variably reset by the intrusion of the South Mountain Batholith at ca. 380 Ma. Other samples in this part of the basin show partial post-depositional resetting. Younger Horton Group metamorphic rocks in the eastern Windsor Basin contain many grains with ages of ca. 370–360 Ma, suggesting derivation from the central core of the South Mountain Batholith or the Musquodoboit Pluton. Horton Group sandstones from the western part of the St. Marys Basin contain muscovite derived from the Liscomb Complex along with metamorphic muscovite variably reset by the intrusion of this complex. In general, our data suggest predominant northward dispersion of muscovite from the Meguma terrane to the Horton Group and a lack of axial transport along the Horton grabens through central Nova Scotia, a pattern compatible with tectonic models in which the Meguma terrane is ramped over the Avalon terrane. Muscovite ages obtained for the Chaswood Formation compare well with those from the Horton Group rocks in the western St. Marys Basin. These rocks may have been exposed to rapid erosion by reactivation of the Cobequid–Chedabucto fault zone in the Early Cretaceous and the resulting sediments were perhaps transported to depositional sites along northeast-trending faults. Unlike the detrital monazites in these rocks, there is no evidence that any of the detrital muscovites came from distal sources outside the Meguma terrane.
13
Feng, R., R. Kerrich, S. McBride e E. Farrar. "40Ar/39Ar age constraints on the thermal history of the Archean Abitibi greenstone belt and the Pontiac Subprovince: implications for terrane collision, differential uplift, and overprinting of gold deposits". Canadian Journal of Earth Sciences 29, n. 7 (1 luglio 1992): 1389–411. http://dx.doi.org/10.1139/e92-112.
Testo completoAbstract (sommario):
40Ar/39Ar mineral age spectra of granitic and metamorphic rocks, in conjunction with existing conventional zircon geochronology, indicate that at least two major late Archean thermal events affected tectonic blocks of the Abitibi Southern Volcanic Zone (SVZ) and the juxtaposed Pontiac Subprovince. The earlier thermal activity (2690–2670 Ma) was accompanied by the intrusion of voluminous syntectonic plutons and caused low-pressure, greenschist-facies metamorphism in the SVZ and intermediate-pressure metamorphism in the Pontiac Subprovince. The second thermal event (2660–2630 Ma) was coeval with the emplacement of syncollisional, S-type garnet–muscovite granites in the Pontiac Subprovince and the higher grade Lacorne block of the Abitibi SVZ, and reset the K–Ar systems in preexisting rocks.Magmatic amphibole from the syntectonic Round Lake batholith (~2695 Ma U–Pb zircon age) of the Abitibi SVZ has a slightly disturbed Ar release spectrum with an upper plateau age of 2669 ± 6 Ma, signifying that the low-grade Round Lake block cooled through 500 °C at a slow rate. Amphiboles in syntectonic batholiths from the higher grade Lacorne block and the Pontiac Subprovince have substantially disturbed Ar release spectra, with high-temperature steps giving apparent ages of 2681 ± 4 to 2679 ± 4 Ma; these overlap zircon ages of 2690–2670 Ma, indicating relatively rapid cooling through the amphibole blocking temperature.Metamorphic rocks (amphibolites) from the Lacorne block and the Pontiac Subprovince contain amphiboles with substantially disturbed 40Ar/39Ar release spectra and higher temperature step ages of 2677 ± 6 to 2670 ± 5 Ma, representing the minimum formation age. Fine-grained muscovite and biotite (180–250 μm) from mica schists also have disturbed Ar release patterns, but much younger apparent ages at high-temperature release steps (2581–2523 Ma for muscovite, 2562–2455 Ma for biotite) than the amphiboles.Coarse-grained muscovites from pegmatites associated with syncollision, S-type garnet–muscovite granites (2644 ± 13 Ma) in the Lacorne block and Pontiac Subprpvince show undisturbed or slightly disturbed Ar release spectra and magmatic δ18Oquartz–muscovite = 1.8–3.5‰, with total integrated ages of 2615 ± 10 to 2594 ± 7 Ma (Lacorne) and 2572 ± 6 Ma (Pontiac), respectively, indicating different uplift rates for the two terranes. Amphiboles (~2680 Ma) from metamorphic rocks in the Lacorne block and Pontiac Subprovince and from the Round Lake batholith are disturbed, whereas coarse-grained muscovites from the pegmatites (2644 ± 13 Ma) are relatively undisturbed. This indicates that the disturbance of the amphiboles may have been caused by a thermal event that preceded or was coeval with the emplacement of the garnet–muscovite granite suite, rather than being a grain-size effect.These results are consistent with a model whereby early subduction of oceanic lithosphere beneath the Abitibi SVZ (2740–2680 Ma), and separately under the Pontiac Subprovince, was responsible for syntectonic batholiths and the first thermal event. Collision with the Abitibi SVZ and local underthrusting of the Pontiac Subprovince at about 2670–2630 Ma caused the second major thermal event and partial melting of the underthrust Pontiac-type metasediments to form the garnet–muscovite granites. Later differential uplift exposed the entire Pontiac Subprovince and the Lacorne block as a tectonic window of underthrust Pontiac in the Abitibi SVZ. Resetting of several isotopic systems, including apparent younger ages of gold mineralization, is probably related to this late collisional, tectonothermal overprinting event. Fluid and (or) thermal events at ≥275 °C influenced the Kirkland Lake – Cadillac fault down to 2513 ± 10 Ma, as indicated by a plateau age of postkinematic biotite in the fault. The fault was intermittently reactivated over a period of 440 Ma, from ~2690 Ma to ≤2250 Ma.
14
Stuart, F. M. "The exhumation history of orogenic belts from 40Ar/39Ar ages of detrital micas". Mineralogical Magazine 66, n. 1 (febbraio 2002): 121–35. http://dx.doi.org/10.1180/0026461026610017.
Testo completoAbstract (sommario):
AbstractThe exhumation history of mountain belts can be derived from radiometric dating of detrital mineral grains in proximal and distal post- and synorogenic sediments. The application of single-crystal dating techniques avoids the averaging effect that characterizes multi-grain and whole-rock techniques and allows the identification of populations of grains with distinct thermal histories. Of the major single crystal dating methods available, 40Ar/39Ar dating of detrital K-bearing minerals, in particular white mica, is perhaps the most versatile and widely applied technique. For a closure temperature of Ar of 350–400°C, muscovite 40Ar/39Ar ages record the time a rock mass passed through 8–10 km beneath actively eroding mountain belts. Detrital muscovit ages eroded from orogenic mountain belts have been used extensively to identify the provenance of sediments from source regions with distinct thermal histories, determine the history and rate of exhumation of the source region, and provide an upper limit on the sediment age. Here I review the principles of 40Ar/39Ar dating of detrital muscovite and illustrate the method with examples showing how the provenance and the thermal history of sediment source regions derived from such studies can be used to constrain the exhumation and tectonic history of orogenic belts.
15
Edwards, Rebecca M. "40Ar/39Ar geochronology of the Main Cental Thrust (MCT) region: Evidence for late Miocene to Pliocene disturbances along the MCT, Marsyangdi River valley, west-central Nepal Himalaya". Journal of Nepal Geological Society 10 (1 aprile 1995): 41–46. http://dx.doi.org/10.3126/jngs.v10i0.36342.
Testo completoAbstract (sommario):
A series of 40Ar/39Ar radiometric age data on biotites and muscovites from the MCT zone in the Marsyangdi River valley in west-central Nepal indicates that disturbances along the MCT occurred in the late Miocene to Pliocene, significantly post-dating the major deformation event of 20 Ma. The biotite and muscovite cooling ages from within 5 km on either side of the MCT range from 2.6 Ma to 9.4 Ma. Biotite cooling ages as young as 2.9 and 3.1 Ma have been found within one km of the MCT. Other ages are younger than 5 Ma. and almost all cooling ages from the area younger than 9.4 Ma.
16
Morishita, Yuichi, e Yoshiro Nishio. "Ore Genesis of the Takatori Tungsten–Quartz Vein Deposit, Japan: Chemical and Isotopic Evidence". Minerals 11, n. 7 (15 luglio 2021): 765. http://dx.doi.org/10.3390/min11070765.
Testo completoAbstract (sommario):
The Takatori hypothermal tin–tungsten vein deposit is composed of wolframite-bearing quartz veins with minor cassiterite, chalcopyrite, pyrite, and lithium-bearing muscovite and sericite. Several wolframite rims show replacement textures, which are assumed to form by iron replacement with manganese postdating the wolframite precipitation. Lithium isotope ratios (δ7Li) of Li-bearing muscovite from the Takatori veins range from −3.1‰ to −2.1‰, and such Li-bearing muscovites are proven to occur at the early stage of mineralization. Fine-grained sericite with lower Li content shows relatively higher δ7Li values, and might have precipitated after the main ore forming event. The maximum oxygen isotope equilibrium temperature of quartz–muscovite pairs is 460 °C, and it is inferred that the fluids might be in equilibrium with ilmenite series granitic rocks. Oxygen isotope ratios (δ18O) of the Takatori ore-forming fluid range from +10‰ to +8‰. The δ18O values of the fluid decreased with decreasing temperature probably because the fluid was mixed with surrounding pore water and meteoric water. The formation pressure for the Takatori deposit is calculated to be 160 MPa on the basis of the difference between the pressure-independent oxygen isotope equilibrium temperature and pressure-dependent homogenization fluid inclusions temperature. The ore-formation depth is calculated to be around 6 km. These lines of evidence suggest that a granitic magma beneath the deposit played a crucial role in the Takatori deposit formation.
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Ilevbare, M., e A. Orisamika. "Geochemical Characterization and Economic Potential of Emure and Ijero Ekiti Pegmatites in Southwest Nigeria". Nigerian Journal of Technology 40, n. 1 (23 marzo 2021): 37–43. http://dx.doi.org/10.4314/njt.v40i1.6.
Testo completoAbstract (sommario):
Global demand increase for rare metals deposits has re-enacted the search for economically viable deposits. Precambrian pegmatites occurring as near dykes and massive types were studied for Emure-Ekiti and Ijero-Ekiti respectively, with the aim of characterizing them geochemically and determining their possible economics values. A total of twelve samples comprising seven from Emure-Ekiti, three whole rock muscovite extract for Ijero-Ekiti were analysed for major and trace elements using X-ray fluorescence method. Thin sections prepared for the Emure-Ekiti pegmatites show that quartz, microcline are major mineral constituents. The geochemical results reveals that the Emure-Ekiti and the whole rock samples of Ijero-Ekiti are considerably siliceous, with an average value of 68.72% and 68.6% respectively, while the muscovites extracts average 48.86%. Mean values of major oxides for the Emure, Ijero[whole rock, muscovite] are as follows; Al2O3 - 20.42%, [13.74%, 35.15%]; Fe2O3 - 1.83%, [1.24%, 2.19%]; MgO - 0.013%, [0.029%, 1.04%]; CaO - 0.02%, [0.34%, 2.4%]; Na2O – 1.01%, [4.40%, 1.045%]; K2O – 3.17%, [2.77%, 11.07%]. Trace and rare-earth elements result shows that the Emure-Ekiti pegmatites is “barren” – depleted in rare metals Ta, Nb, Cs, Sn, Rb, etc, and compare favourably with Apomu, Ago-Iwoye and Ijebu-Ife barren pegmatites. On the other hand, two of the whole rock samples are mineralized – fairly enriched in rare metals Ta, Nb, Rb while the remaining sample and the muscovite extract are barren; as depicted by the Rb vs Rb plot and when compared to the other rare metal pegmatites across the world.
18
Ohryzko, Volodymyr. "Why Russia Will Never Make It". Diplomatic Ukraine, n. XXI (2020): 717–43. http://dx.doi.org/10.37837/2707-7683-2020-36.
Testo completoAbstract (sommario):
The article deals with the complex and multifaceted issue of self-esteem of the Muscovite population. The centuries-old seclusion from Western European processes has forged the psychological type of a ‘lonely people’ constantly looking for its shore but never quite finding it. Such separateness and otherness have led to the cultivation in the public consciousness of a stereotypical higher calling, special mission, mysteriousness, etc. The permanent ‘closed solitude’ has given rise to another psychological phenomenon – suspiciousness and aversion to everything foreign. For the sake of painting an in-depth psychological portrait of Muscovites, the author cites, for instance, controversial thoughts of Nikolai Berdyaev, who analyses the three most important elements of the Russian mindset – its perception of statehood, ethnicity, and religion. Over time, the psychological knots and traumas tied up during the formative stage of the Muscovite nation have eventually transformed into paranoid ideas of its exceptionalism and permissiveness. The author steadily justifies that the psychological type of the Russian people is hazardous for everyone around, particularly for Russia itself. It has not established itself as a democratic, liberal, free, and social state, as it cannot – and will not – do it. Therefore, its internal repressions and international aggression are an evolutionary dead end and a catalyst for collapse. Keywords: Muscovy, psychological type, Berdyaev, Putin, chauvinism, propaganda, rapaciousness.
19
Aalto, K. R., W. D. Sharp e P. R. Renne. "40Ar/39Ar dating of detrital micas from Oligocene-Pleistocene sandstones of the Olympic Peninsula, Klamath Mountains, and northern California Coast Ranges: provenance and paleodrainage patterns". Canadian Journal of Earth Sciences 35, n. 7 (1 luglio 1998): 735–45. http://dx.doi.org/10.1139/e98-025.
Testo completoAbstract (sommario):
Sandstones of the Eocene-Miocene Hoh assemblage of the Olympic Peninsula and Late Oligocene - Miocene Weaverville Formation (Klamath Mountains) were studied to determine if the Hoh sandstones could be tectonically transported equivalents of the Weaverville Formation. Distinct Hoh sandstone types exposed between La Push and the Hoh River include (1) highly brecciated and veined, quartz-poor, mica-poor volcaniclastic sandstone preserved in mélange blocks; and (2) relatively unveined and unbrecciated, quartzose micaceous sandstone preserved in mélange blocks and bounding turbidites. 40Ar/39Ar laser heating analyses of single crystals of detrital muscovite grains from quartzose Hoh sandstones yield Late Cretaceous - early Tertiary ages, consistent with contributions to Hoh detritus from the Idaho batholith. Volcaniclastic mélange block sandstones could be derived from older Tertiary volcanic terranes of the northeast Olympic Peninsula, or from Mesozoic accretionary terranes. Analyses of muscovites from the fluviatile Weaverville Formation of the Klamath Mountains, California, yield Pennsylvanian ages with a possible source within the Klamath Central Metamorphic terrane. No provenance link was detected between the Hoh assemblage and Weaverville Formation. Analyses of muscovites from Pliocene and Pleistocene sandstones of the Wildcat Group of the northern California Coast Ranges yield both Cretaceous - early Tertiary and Pennsylvanian ages, suggesting derivation from both local and distant sources. Although an ancestral "Snake River" paleodrainage system to the Klamath Mountains region was shutoff during Weaverville sedimentation, it may have been reestablished in the Late Miocene when Idaho-derived sediments were again transported to northwestern California.
20
Ерусалимский, К. Ю. "Mapping the Borders of Muscovy and Rus’ Representations of the “Muscovite People” in the European Cartography and Toponymy of the 16–18th сс." Диалог со временем, n. 78(78) (24 aprile 2022): 175–88. http://dx.doi.org/10.21267/aquilo.2022.78.78.011.
Testo completoAbstract (sommario):
В статье рассмотрены репрезентации «Московии» и «Белой Руси» на картах XVI в. и развитие этих ренессансных хоронимов в картографии XVII–XVIII вв., а также изучена «московская» топонимика на землях Великого княжества Литовского и Короны Польской. Московия и населяющие ее московиты возникли на картах в 1500-1540-е гг. на малоизвестных землях, которые не рассматривались до середины XVI в. как единое политическое целое, однако и позднее ограничивались в своем господствующем статусе благодаря ряду картографических приемов. The article deals with the representations of „Muscovy“ and „Alba Russia“ on the 16th century maps and developments of these Renaissance choronyms in the 17–18th cс., and „Muscovite“ toponymy on the lands of the Grand Duchy of Lithuania and the Polish Crown. The Muscovy and populating her Muscovites emerged on the maps ca. 1500–1540s as cartographic symbols on the understudied lands, which were not considered as political unit until the mid-16th century, and later were also limited in their domineering status in these lands by special cartographic means.
21
Gomes, M. E. P., e A. M. R. Neiva. "Chemical zoning of muscovite from the Ervedosa granite, northern Portugal". Mineralogical Magazine 64, n. 2 (aprile 2000): 347–58. http://dx.doi.org/10.1180/002646100549247.
Testo completoAbstract (sommario):
AbstractThe tin-bearing muscovite granite from Ervedosa contains unzoned primary muscovite. This Hercynian S-type granite was hydrothermally altered at the stanniferous quartz vein walls and contains three types of muscovite: (1) very small unzoned muscovite replacing albite; (2) small unzoned hydrothermal muscovite replacing K-feldspar and quartz; and (3) zoned subhedral muscovite.In the zoned muscovite, the core has a composition similar to that of magmatic muscovite from the unaltered granite, while the rim has a composition similar to that of hydrothermal muscovite replacing K-feldspar and quartz in the altered granite. The rim corresponds to a late overgrowth richer in the celadonitic component than the core. Infiltrated mineralizing fluids reacted with biotite and K-feldspar of the unaltered granite. We interpret the rim of muscovite to have precipitated from these solutions.
22
Jia, Feifei, e Shaoxian Song. "Preparation of monolayer muscovite through exfoliation of natural muscovite". RSC Advances 5, n. 65 (2015): 52882–87. http://dx.doi.org/10.1039/c5ra07749d.
Testo completo
23
Ansdell, Kevin M., e T. Kurtis Kyser. "The geochemistry and fluid history of the Proterozoic Laurel Lake Au–Ag deposit, Flin Flon greenstone belt". Canadian Journal of Earth Sciences 28, n. 2 (1 febbraio 1991): 155–71. http://dx.doi.org/10.1139/e91-016.
Testo completoAbstract (sommario):
The Laurel Lake Au–Ag deposit is situated 25 km southwest of Flin Flon in the Proterozoic Flin Flon Domain and consists of branching quartz–muscovite–pyrite–tennantite–chalcopyrite–sphalerite–galena–electrum–carbonate veins (stage 1) surrounded by a widespread zone of sericitized and pyritized Amisk Group felsic volcanic rocks. The deposit has been deformed and metamorphosed during the Hudsonian orogeny and is crosscut by nonauriferous quartz–dolomite–tourmaline–pyrite veins (stage 2). The timing of mineralization, the lack of obvious relation to a major shear zone, and high base metal sulphide and Ag/Au ratio (5:1) distinguish this deposit from epigenetic mesothermal gold deposits in the Flin Flon Domain. Fluid inclusion and stable-isotope data indicate that the mineralizing fluids had a high temperature (>300 °C), were saline (>10.3 wt.% NaCl equivalent) and CO2 bearing and had an isotopic composition similar to modified seawater. This fluid leached sulphur, base metals, and precious metals as it interacted with Amisk Group volcanic rocks. The hydrogen isotopic compositions of fine-grained muscovites in the surrounding altered felsic volcanic rocks have been reset during later metamorphism, whereas the coarse stage 1 vein muscovites have partially preserved their primary hydrogen isotopic compositions and fluorine contents. Stage 2 veins were deposited from low-salinity (<6.4 wt.% NaCl equivalent), CO2-bearing fluids, which also have the hydrogen and oxygen isotopic compositions of modified seawater. The Laurel Lake deposit has fluid, vein, and alteration characteristics that distinguish it from both epithermal and mesothermal deposits, and they can be explained by the involvement of modified seawater.
24
Abdul Kudus, Muhammad Helmi, Hazizan Md Akil, Muhammad Razlan Zakaria e Siti Shuhadah Md Saleh. "Synthesis and Characterization of Novel Hybrid MWCNT-Muscovite Composite Filler". Applied Mechanics and Materials 754-755 (aprile 2015): 106–9. http://dx.doi.org/10.4028/www.scientific.net/amm.754-755.106.
Testo completoAbstract (sommario):
A novel hybrid carbon nanotube-muscovite (CNT-muscovite) compound was synthesized via chemical vapour deposition (CVD) by directly grown CNT on muscovite particles. The synthesis of CNT using nickel catalyst and muscovite as a substrate material is rarely found. Morphological analysis using scanning electron microscope (SEM) and high resolution transmission electron microscope (HRTEM) showed that the CNT was successfully grown on muscovite flaky particles. The CNT-muscovite compound can be potentially used as a new class of filler in polymer composites technology.
25
Puziewicz, Jacek, e Anna Pietranik. "Two-mica andalusite-bearing granite with no primary muscovite: constraints on the origin of post-magmatic muscovite in two-mica granites". Geoscience Records 3, n. 1 (1 dicembre 2016): 7–17. http://dx.doi.org/10.1515/georec-2016-0006.
Testo completoAbstract (sommario):
Abstract The two-mica granite from Gęsiniec (Strzelin Granitic Massif, SW Poland) consists of quartz, K-feldspar, normally zoned plagioclase (30 ± 7 % An), subordinate biotite and muscovite and magmatic andalusite. Andalusite crystallised before the outer parts of plagioclase grains were formed. Biotite has constant Fe/(Fe + Mg) ratio of approximately 0.81. Five textural types of muscovite occur in the granite: (1) muscovite replacing andalusite, (2) embayed interstitial muscovite, (3) muscovite forming aggregates with biotite, (4) muscovite accompanying biotite and chlorite in microfissures and (5) fine muscovite forming fringes at the contact between larger muscovite plates and K-feldspar. They are commonly associated with albite. Crystallisation of muscovite started significantly below the granite solidus, mostly by the replacement of andalusite. Formation of muscovite continued during cooling of host rock. The growth of individual plates was initiated at different undercoolings and the plates whose crystallisation was frozen at different stages of growth occur. Those that were formed earlier are richer in titanium and iron relative to the later ones. As the rock contains no Ti and Fe saturating phases, the content of Ti and Mg in muscovite depends on their local availability. The homogeneous Fe/(Fe + Mg) ratio of biotite indicates that it was re-equilibrated at the post-magmatic stage.
26
Ruiz Cruz, M. D., D. Morata, E. Puga, L. Aguirre e M. Vergara. "Microstructures and interlayering in pyrophyllite from the Coastal Range of central Chile: evidence of a disequilibrium assemblage". Clay Minerals 39, n. 4 (dicembre 2004): 439–52. http://dx.doi.org/10.1180/0009855043940146.
Testo completoAbstract (sommario):
AbstractPyrophyllite from a Triassic sedimentary formation from the Coastal Range of Chile has been investigated by transmission/analytical electron microscopy (TEM/AEM). The mineral assemblage includes pyrophyllite, muscovite, paragonite, a kaolin mineral, boehmite, rutile and hematite. The textures indicate that the protolith was a volcanoclastic rock. Petrographic evidence, chemistry, and the mineral assemblage suggest the intense leaching of the parent rock by a weathering process, before the metamorphic episode, to create the protolith for the pyrophyllite. Pyrophyllite always grows from the kaolin mineral, and both phases show close orientation relationships. The presence of parallel intergrowths of pyrophyllite and muscovite indicate that muscovite also grew from the kaolin mineral. Nevertheless, the composition of muscovite suggests that this phase must also form from another precursor, probably Al smectite. The AEM data and textural relationships between pyrophyllite and muscovite reveal the presence of two generations of muscovite and suggest that Na-rich muscovite recrystallized into a Na-free muscovite and paragonite.
27
Keenan, Edward L. "Muscovite Political Folkways". Russian Review 45, n. 2 (aprile 1986): 115. http://dx.doi.org/10.2307/130423.
Testo completo
28
Kollmann, Nancy Shields. "A Muscovite Republic?" Slavic Review 80, n. 3 (2021): 492–97. http://dx.doi.org/10.1017/slr.2021.152.
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29
Martin, Janet. "Multiethnicity in Muscovy: a Consideration of Christian and Muslim Tatars in the 1550s-1580s". Journal of Early Modern History 5, n. 1 (2001): 1–23. http://dx.doi.org/10.1163/157006501x00014.
Testo completoAbstract (sommario):
AbstractAs persistent territorial expansion transformed the predominantly Slavic, Orthodox Christian Muscovite state into a multiethnic empire by the mid-16th century, the Church articulated an ideology that set adoption of the Orthodox faith as the fundamental criterion for admission and assimilation into Muscovite society. An examination of Tatars in Muscovite service during the 1550s-1580s, however, reveals that in practice religious affiliation was not the sole factor determining acceptance into Muscovite society. Orthodox Christian Tatars, both members of the Chingissid elite and common servicemen, entered Muscovite society, but their ethnic Tatar identity continued to distinguish them from their Muscovite peers and inhibit their complete assimilation. Muslim Tatars, also represented at both elite and common levels, were not excluded from Muscovite society, but also found positions in it and were treated in a manner similar to that of their Orthodox brethren.
30
Wang, Yubin, Yan Wang, Wei Xiao, Yaru Wei e Shuqin Li. "Effect of Cu2+ on the Activation to Muscovite Using Electrochemical Pretreatment". Minerals 10, n. 3 (25 febbraio 2020): 206. http://dx.doi.org/10.3390/min10030206.
Testo completoAbstract (sommario):
In this study, electrochemistry pretreatment flotation of muscovite was carried out and the flotation behavior and mechanism of muscovite in the system of sodium oleate and Cu2+ion was characterized by solution pH value detection, solution conductivity detection, zeta potential, infrared spectrum and the electronic energy spectrum. The results indicated that under the conditions of muscovite mass of 10.00 g, pulp mass concentration of 13.33%, flotation speed of 1750 r/min, sodium oleate concentration of 9.20 × 10−4 mol/L and Cu2+ concentration of 6 × 10−5 mol/L, electrochemical pretreatment of Cu2+ could strengthen the activation of muscovite. Electrochemical pretreatment of Cu2+ solution can inhibit the hydrolysis of copper ions, increase the content of Cu2+ in the solution, strengthen the adsorption of Cu2+ on the muscovite surface, and enhance the electrostatic adsorption of sodium oleate on the muscovite surface, thereby strengthening the physical and chemical adsorption of sodium oleate on the muscovite surface.
31
Kontak, D. J., J. Tuach, D. F. Strong, D. A. Archibald e E. Farrar. "Plutonic and hydrothermal events in the Ackley Granite, southeast Newfoundland, as indicated by total-fusion 40Ar/39Ar geochronology". Canadian Journal of Earth Sciences 25, n. 8 (1 agosto 1988): 1151–60. http://dx.doi.org/10.1139/e88-113.
Testo completoAbstract (sommario):
Results of total-fusion 40Ar/39Ar dating (eight biotites, four muscovites, and one hornblende) of magmatic and hydrothermal stages of the high-silica, chemically zoned Ackley Granite indicate three distinct episodes of magmatic activity, viz. ≥ 410, 378–374, and 355 Ma, and that the metallogenic system (W–Sn, Mo) evolved synchronously with only one of the magmatic phases.The oldest suite is indicated by two biotite dates at 410.4 ± 4.4 and 392.5 ± 7.6 Ma, which are themselves considered as representing partial resetting related to a tectonothermal event of Acadian age. Thus, the 410 Ma age offers the best estimate of intrusion, although it must be considered a minimum. The main magmatic pulse for the Ackley Granite is indicated by dates between 378 and 374 Ma, with most of these phases occurring in the southern part of the complex. Concordant hornblende–biotite ages (374.8 ± 3.8 and 372.3 ± 4.8 Ma, respectively) for one of the southern phases (Rencontre Lake granite) suggests rapid cooling for this part of the complex. In contrast, the data for a contemporaneous intrusion (Kepenkeck granite) in the northern part of the Ackley Granite are discordant, with a muscovite–biotite pair yielding ages of 378.4 ± 4.8 and 367.7 ± 4.3 Ma, respectively. Four remaining biotite dates, widely distributed within the southern part of the Ackley Granite, gave similar ages of ca. 368 Ma.Three hydrothermal muscovites from mineralized greisen zones along the soumern margin of the granite are dated at 371.3 ± 4.5, 371.3 ± 5.4, and 373.5 ± 4.0 Ma, essentially coeval with the main magmatic event of the Ackley Granite. Since these paragenetically late muscovites give slightly older ages than the magmatic biotites of the second pulse, it is suggested that the ambient temperature for a large part of the Ackley Granite remained in excess of the 250–300 °C biotite blocking temperature for several million years after initial intrusion.A third and presumably magmatic event, presently of unknown dimensions, occurred at 355 Ma. The coincidence of this age with previously published Rb–Sr whole-rock isochron dates of 355 Ma for the Ackley Granite might indicate that this younger magmatic event was in part responsible for resetting the Rb–Sr systematics.
32
AKINAY, Yuksel, e Ihsan Nuri AKKUŞ. "Preparation and characterization of CuO/Muscovite flakes pearlescent pigment with UV absorption and high NIR reflectance". Academic Perspective Procedia 2, n. 2 (27 ottobre 2019): 265–70. http://dx.doi.org/10.33793/acperpro.02.02.41.
Testo completoAbstract (sommario):
The CuO nanoparticles were deposited onto muscovite flakes using sol-gel methods. The thermal, conductivity, optic and structural properties of obtained pigments (CuO/Muscovite) were studied. Hence, the prepared pigments were characterized via using scanning electronic microscopy (SEM) and ultraviolet–visible spectrophotometer (UV-Vis). The results show that CuO was coated on the surface of muscovite flakes uniformly. The obtained pigments show the more stable thermal properties than those obtained from undeposited flakes. The CuO/Muscovite pigments showed high ultraviolet shielding performance. In addition that CuO/Muscovite pigments exhibited higher near-infrared (NIR) reflectance than those of pure-CuO.
33
Li, Yao, Hongjuan Sun, Tongjiang Peng, Hao You, Yating Qin e Li Zeng. "Effects of muscovite matrix on photocatalytic degradation in TiO2/muscovite nanocomposites". Applied Clay Science 179 (ottobre 2019): 105155. http://dx.doi.org/10.1016/j.clay.2019.105155.
Testo completo
34
Pipera, Kyriaki, Antonis Koroneos, Triantafyllos Soldatos, Zoltán Pécskay e Georgios Christofides. "K/Ar mineral geochronology of the northern part of the Sithonia Plutonic Complex (Chalkidiki, Greece): implications for its thermal history and geodynamic interpretation". Geologica Carpathica 64, n. 2 (1 aprile 2013): 133–40. http://dx.doi.org/10.2478/geoca-2013-0009.
Testo completoAbstract (sommario):
Abstract New K/Ar mineral ages of thirty nine samples (biotite, muscovite, K-feldspar) from the two-mica granodiorite to granite and leucogranite of the northern part of the Sithonia Plutonic Complex (Chalkidiki, Greece) are given in the present study. These data along with existing Rb/Sr mica and U/Pb zircon ages are used to investigate the thermal history of the plutonic complex and shed light on the process that affected it, and caused discordant Rb/Sr and K/Ar mineral ages. The K/Ar mineral dating yielded ages ranging from 38 to 49 Ma for muscovites, 32 to 47 Ma for biotites and 37 to 43 Ma for K-feldspars, respectively. The comparison of the K/Ar, Rb/Sr and U/Pb mineral ages and the closure temperatures of the different isotopic systems for the different minerals indicate a rapid cooling rate for the Sithonia pluton. The latter supports the hypothesis that the pluton was formed in a post orogenic extensional regime. Moreover, the K/Ar mineral isochrones indicate that a reheating of the pluton took place before 37 Ma and partially rejuvenated the K/Ar and Rb/Sr isotopic system of the minerals
35
Anand, RR, e RJ Gilkes. "Muscovite in Darling Range bauxitic laterite". Soil Research 25, n. 4 (1987): 445. http://dx.doi.org/10.1071/sr9870445.
Testo completoAbstract (sommario):
Darling Range bauxitic laterite contains 0-17% silt size, Na-rich, 2M1 muscovite which is most abundant in laterite developed from granitic parent rocks. Muscovite grains show evidence of dissolution, but there has been no formation of dioctahedral vermiculite. Muscovite is clearly a much more resistant mineral than the feldspar, biotite and chlorite in the parent materials that have completely altered to secondary minerals. Muscovite is therefore a significant constituent of Darling Range bauxitic laterite and consequently poses problems in bauxite processing.
36
Omar, M. F., Nur Suhaili Abd Wahab, Hazizan Md Akil, Zainal Arifin Ahmad, Mohd Fadli Ahmad Rasyid e N. Z. Noriman. "Effect of Surface Modification on Strain Rate Sensitivity of Polypropylene/Muscovite Layered Silicate Composites". Materials Science Forum 803 (agosto 2014): 343–47. http://dx.doi.org/10.4028/www.scientific.net/msf.803.343.
Testo completoAbstract (sommario):
Surface modification is one of the treatment methods that can be implemented to improve the strain rate sensitivity of composite materials. In this study, both untreated and treated polypropylene/muscovite layered silicate composites were tested under static and dynamic loading up to 1100 s-1 using the universal testing machine and the split Hopkinson pressure bar apparatus, respectively. Muscovite particles were treated with lithium nitrate and cetyltrimethylammonium bromide as a surfactant through ion exchange treatment. Results show that the treated polypropylene/muscovite specimens with fine state of dispersion level shows better rate of sensitivity as compared to untreated polypropylene/muscovite specimens under a wide range of strain rate investigated. Apart from that, the rate of sensitivity of both tested polypropylene/muscovite layered silicate composites also show great dependency on the strain rate sensitivity was steadily increased with increasing strain rate. Unfortunately, the thermal activation values show contrary trend. Key words: Ion exchange treatment; Strain rate sensitivity; Muscovite particles; Split Hopkinson pressure bar apparatus; Strain rates
37
Xue, Nannan, Qiushi Zheng e Yimin Zhang. "Function of Interface Deposition of Calcium Sulfate in Pressure Acid Leaching of Black Shale-Hosted Vanadium". Minerals 10, n. 11 (26 ottobre 2020): 952. http://dx.doi.org/10.3390/min10110952.
Testo completoAbstract (sommario):
During pressure acid leaching process of black shale-hosted vanadium, increasing the reaction interface of muscovite dissolution can enhance the vanadium release. In this paper, calcium sulfate (CaSO4) deposition behavior and its effect on muscovite under K2SO4 assistance were focused on for demonstrating the function of CaSO4 on vanadium leaching from the black shale. Results showed that as K2SO4 mediated, the apparent activation energy of vanadium leaching and the apparent reaction order of sulfuric acid decreased from 24.37 kJ/mol to 16.63 kJ/mol and 2.7 to 1.9, respectively. The leaching rate and dependence on pH value were modified. The vanadium leaching acceleration owed to CaSO4 deposition on muscovite in the black shale. The ion absorption stimulations found that Ca2+ is confirmed to be easily absorbed on the six-membered ring cavity of silicon-oxygen tetrahedrons in muscovite structure prior to K+ and Na+. Meanwhile, SO42− provides two oxygen atoms to bond with Ca2+ absorbed on muscovite (001) surface. The continuous absorption and bonding create CaSO4 deposition on muscovite (001) surface which also involves the load transmitting. The stress load transmitting correlates to pore formation in muscovite particles. It was proved that massive micropores initiated and proliferated in the existing pores under K2SO4 assistance. The porosity caused by CaSO4 deposition greatly increased the reaction interface of muscovite dissolution and accelerate internal diffusion of H+ to the reaction interface, which can significantly weaken the vanadium leaching dependence on acid.
38
Ahmad Rasyid, Mohd Fadli, Md Akil Hazizan e Jamaliah Mohd Sharif. "Influence of Organo-Clay on Mechanical and Thermal Properties of O-Muscovite/PP Layered Silicate Nanocomposite". Advanced Materials Research 364 (ottobre 2011): 174–80. http://dx.doi.org/10.4028/www.scientific.net/amr.364.174.
Testo completoAbstract (sommario):
O-Muscovite/PP Layered Silicate Nanocomposites were prepared via melt compounding using different filler content. Muscovite was organomodified with Cetyldimethylethylammonium bromide (CEDAB). The thermal and mechanical properties of nanocomposites, based on polypropylene (PP) filled by organo-clay (O-Muscovite), were studied in order to clarify the effect of O-Muscovite on the O-Muscovite/PP layered silicate nanocomposites by WAXD, TEM and DSC analyses. XRD indicated that O-Mica layers were intercalated and dispersed into polypropylene. Analysis of test data shows that, addition of organo-clay improved mechanical properties of O-Mica/PP nanocomposites. With the incorporation of 5 wt% O-Mica (optimal filler loading) into polypropylene Izod impact increased to 23%. The DSC analyses have shown that the influence of organo-clay on the thermal properties of material was significant in composites with O-Mica as fillers, compared to virgin PP. The enhancements of properties can be caused by the formation of intercalated and exfoliation nanocomposite structure at this clay content and stronger interaction of O-Mica with polymer matrix. At a higher filler loading, degradation in mechanical properties maybe attributes to the formation of agglomerated clay tactoids. O-Muscovite/PP Layered Silicate Nanocomposites were prepared via melt compounding using different filler content. Muscovite was organomodified with cetyltrimethylammoniumbromide (CTAB). The thermal and mechanical properties of nanocomposites, based on polypropylene (PP) filled by organo-clay (O-Muscovite), were studied in order to clarify the effect of O-Muscovite on the O-Muscovite/PP layered silicate nanocomposites by WAXD, TEM and DSC analyses. XRD indicated that O-Mica layers were intercalated and dispersed into polypropylene. It was found that the mechanical and thermal properties of organo-clay nanocomposite possess better properties as compared to the unmodified clay nanocomposites. The reason was partly due to the formation of intercalated and exfoliation nanocomposite structure at this clay content and stronger interaction of O-Mica with polymer matrix.
39
Jiang, Hao, Ya Gao, Sultan Khoso, Wanying Ji e Yuehua Hu. "Interpretation of Hydrophobization Behavior of Dodecylamine on Muscovite and Talc Surface through Dynamic Wettability and AFM Analysis". Minerals 8, n. 9 (6 settembre 2018): 391. http://dx.doi.org/10.3390/min8090391.
Testo completoAbstract (sommario):
In this study, a new approach, “dynamic wettability”, and atomic force microscopy (AFM) imaging analysis techniques were successfully used to characterize the hydrophobization mechanism of the collector dodecylamine (DDA) on muscovite and talc surfaces. The attachment of bubbles to the minerals was studied through the dynamic contact angle to gain a detailed understanding of the hydrophobization mechanism of DDA on a muscovite and talc surface. AFM imaging and interaction forces were performed to explain the DDA adsorption mechanism on both minerals. Finally, flotation tests were performed to verify the effectiveness of these techniques. After treatments with DDA, the contact angles became much larger compared to initial angles, particularly for muscovite, and the attachment of bubbles on the talc surface was much easier than muscovite due to its natural hydrophobicity. From AFM imaging, both the muscovite and talc showed a similar tendency; the higher the DDA concentration, the more the adsorbed amount. However, the adsorbed amount of DDA on talc surface was obviously more than that on muscovite. As far as interaction forces are concerned, the maximum attractions occurred at certain different concentrations respectively for muscovite and talc and agreed well with the AFM-imaging results. Moreover, results obtained from flotation tests were promising and quite in agreement with the phenomenon of these techniques.
40
Omar, Mohd Firdaus, Haliza Jaya, Hazizan Md Akil, Zainal Arifin Ahmad, Mohd Fadli Ahmad Rasyid e N. Z. Noriman. "Effect of Organic Modification on Dynamic Compression Properties of Polypropylene/Muscovite Layered Silicate Composites". Materials Science Forum 803 (agosto 2014): 282–87. http://dx.doi.org/10.4028/www.scientific.net/msf.803.282.
Testo completoAbstract (sommario):
In order to improve the mechanical properties of composite materials, one of the renowned techniques that can be applied is the filler modification. Still, no works were concern on this particular matter under dynamic standpoint. Therefore, in this study, both untreated and treated polypropylene/muscovite layered silicate composites were tested under static and dynamic loading up to 1100 s-1 using the universal testing machine (UTM) and the split Hopkinson pressure bar (SHPB) apparatus. Muscovite particles were treated with lithium nitrate and cetyltrimethylammonium bromide as a surfactant through surface modification. Results show that the treated polypropylene/muscovite samples with fine state of dispersion level shows superior mechanical performances as compared to untreated polypropylene/muscovite samples under an extensive range of strain rate investigated. Furthermore, the mechanical properties of both tested polypropylene/muscovite layered silicate composites also display great reliance on the strain rate applied where strength and stiffness properties were gradually increased with increasing strain rate. Key words: Organic modification; Strength and stiffness properties; Muscovite particles; Split Hopkinson pressure bar apparatus; Strain rates
41
Brigatti, Maria Franca, Ermanno Galli, Luca Medici, Luciano Poppi, Giannantonio Cibin, Augusto Marcelli e Annibale Mottana. "Chromium-containing muscovite: crystal chemistry and XANES spectroscopy". European Journal of Mineralogy 13, n. 2 (30 marzo 2001): 377–89. http://dx.doi.org/10.1127/0935-1221/01/0013-0377.
Testo completo
42
Keenan, Edward L. "["Muscovite Political Folkways"]: Reply". Russian Review 46, n. 2 (aprile 1987): 199. http://dx.doi.org/10.2307/130628.
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43
Weickhardt, George G. "Muscovite Law on Monasteries". Russian History 39, n. 1-2 (2012): 13–41. http://dx.doi.org/10.1163/187633112x627193.
Testo completoAbstract (sommario):
The author surveys Muscovite law regulating monasteries, focusing on which courts exercised jurisdiction over monasteries and the legal right to appoint or remove superiors of monasteries. Throughout the Muscovite period secular courts had jurisdiction over lawsuits involving claims to land brought by or against monasteries, and this jurisdiction was confirmed in the 1550 Sudebnik. Lawsuits involving “spiritual matters” were heard by church courts, and the Stoglav confirmed the church courts’ jurisdiction over lawsuits brought by laymen against monastic personnel. The Stoglav also gave the tsar a veto over the appointment of monastic superiors, but many secular officials, prelates and the brothers themselves had influence and authority over the choice of a candidate. While the Stoglav and actual practice required that the brothers obey the superior, there is much evidence that in the management of monasteries the superior sought the consensus of his council of elders. Chapter 13 of the 1649 Ulozhenie constituted a major change in the law. It confided jurisdiction over lawsuits against monasteries and their personnel to a state chancellery staffed by lay judges. The 1666-1667 Church Council, however, restored the jurisdiction of church courts to where it had been prior to 1649. Although the law was unstable throughout the Muscovite period, the monasteries continued to exercise some measure of legal autonomy from the state.
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El-Bahrawi, M. S., N. N. Nagib, S. A. Khodier e H. M. Sidki. "Birefringence of muscovite mica". Optics & Laser Technology 30, n. 6-7 (settembre 1998): 411–15. http://dx.doi.org/10.1016/s0030-3992(98)00074-7.
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Célérier, J., T. M. Harrison e J. Hermann. "Ar diffusion in muscovite". Geochimica et Cosmochimica Acta 70, n. 18 (agosto 2006): A90. http://dx.doi.org/10.1016/j.gca.2006.06.093.
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Mares, V. M., e A. K. Kronenberg. "Experimental deformation of muscovite". Journal of Structural Geology 15, n. 9-10 (settembre 1993): 1061–75. http://dx.doi.org/10.1016/0191-8141(93)90156-5.
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Che Ismail, N. H., e H. M. Akil. "Improving the Flexural Properties of Abs/Muscovite Composites by Introducing Modified Muscovite". Journal of Physics: Conference Series 1082 (agosto 2018): 012016. http://dx.doi.org/10.1088/1742-6596/1082/1/012016.
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Han, Seokyoung, e Haemyeong Jung. "Deformation Microstructures of Phyllite in Gunsan, Korea, and Implications for Seismic Anisotropy in Continental Crust". Minerals 11, n. 3 (11 marzo 2021): 294. http://dx.doi.org/10.3390/min11030294.
Testo completoAbstract (sommario):
Muscovite is a major constituent mineral in the continental crust that exhibits very strong seismic anisotropy. Muscovite alignment in rocks can significantly affect the magnitude and symmetry of seismic anisotropy. In this study, deformation microstructures of muscovite-quartz phyllites from the Geumseongri Formation in Gunsan, Korea, were studied to investigate the relationship between muscovite and chlorite fabrics in strongly deformed rocks and the seismic anisotropy observed in the continental crust. The [001] axes of muscovite and chlorite were strongly aligned subnormal to the foliation, while the [100] and [010] axes were aligned subparallel to the foliation. The distribution of quartz c-axes indicates activation of the basal<a>, rhomb<a> and prism<a> slip systems. For albite, most samples showed (001) or (010) poles aligned subnormal to the foliation. The calculated seismic anisotropies based on the lattice preferred orientation and modal compositions were in the range of 9.0–21.7% for the P-wave anisotropy and 9.6–24.2% for the maximum S-wave anisotropy. Our results indicate that the modal composition and alignment of muscovite and chlorite significantly affect the magnitude and symmetry of seismic anisotropy. It was found that the coexistence of muscovite and chlorite contributes to seismic anisotropy constructively when their [001] axes are aligned in the same direction.
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Du, Pengfei, G. X. Chen, Shiyuan Song, Jiang Wu, Kechen Gu, Dachuan Zhu e Jin Li. "Effect of thermal activation on the tribological behaviors of muscovite particles as lubricant additives in lithium grease". Industrial Lubrication and Tribology 70, n. 3 (9 aprile 2018): 538–43. http://dx.doi.org/10.1108/ilt-11-2016-0288.
Testo completoAbstract (sommario):
Purpose The tribological properties of muscovite and its thermal-treated products as lubricant additives in lithium grease were investigated. The effect of thermal temperature on the crystal structure and tribological properties of muscovite was studied. This study aims to explore the tribological mechanism of muscovite and optimize a proper thermal activation temperature, thus further improving the tribological properties. Design/methodology/approach The crystal structure of muscovite samples was characterized by SEM, TG-DSC, XRD and FTIR. The tribological properties of grease samples were investigated using a four-ball tribotester and the worn surface was analyzed by SEM and EDS. Findings The excellent tribological properties of muscovite can be ascribed to the layer structure and lubricant film formed on the worn surface. Thermal temperature at 500-600°C increases the surface activity and oxygen releasing capability, and thus favors the formation of lubricant film and accordingly further improves the tribological properties. However, the layer structure is destroyed and hard phases such as alumina and amorphous appear after thermal temperature activated beyond 1000°C, as it results in the aggravation of friction and wear. Originality/value To the authors’ knowledge, it is the first to study the effect of thermal temperature on the crystal structure and tribological properties of muscovite. The tribological mechanism of muscovite particle and its thermal-treated products was disclosed.
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Kontak, D. J., e R. F. Cormier. "Geochronological evidence for multiple tectono-thermal overprinting events in the East Kemptville muscovite–topaz leucogranite, Yarmouth County, Nova Scotia, Canada". Canadian Journal of Earth Sciences 28, n. 2 (1 febbraio 1991): 209–24. http://dx.doi.org/10.1139/e91-020.
Testo completoAbstract (sommario):
The East Kemptville muscovite–topaz leucogranite, located in Yarmouth County, Nova Scotia, Canada, is host rock to the only producing primary tin deposit in North America (56 Mt, 0.165% Sn). Previous geochronological studies include (i) Rb–Sr whole-rock analyses of the quartz–topaz greisens, which indicated a date of 337 ± 5 Ma, and (ii) 40Ar/39Ar analyses of greisen muscovite, which indicated apparent plateau dates of ca. 300 Ma. However, the pervasive development of deformational fabrics at East Kemptville suggests that both the Rb–Sr whole-rock and 40Ar/39Ar muscovite ages are at best minimum estimates for the inferred time of mineralization. In the present study, Rb–Sr whole-rock and mineral (muscovite, plagioclase, K-feldspar) analyses and 40Ar/39Ar incremental-step heating of a muscovite separate indicate the following: (i) diffusion of Sr on the whole-rock scale terminated at 344 ± 5 Ma (11 point isochron date), coincident with closure of muscovite to intracrystalline diffusion of Ar (apparent plateau date of 338 ± 2 Ma) and (ii) internal reequilibration of Sr among muscovite, feldspar, and whole rock varied considerably such that Rb–Sr whole rock – muscovite pairs give dates of 361–311 Ma (mean = 330 Ma, n = 7), whereas whole rock – plagioclase – K-feldspar give dates of 276–240 Ma (mean = 254 Ma, n = 7). This younger thermal event is reflected in apparent dates of 269–286 Ma for the low-temperature steps of the 40Ar/39Ar muscovite age spectrum.Collectively the data indicate that the East Kemptville area either cooled slowly over a protracted period of time (ca. 100 Ma) or experienced episodic tectono-thermal activity at ca. 344, 330, and 254 Ma. Examination of previously published geochronological data for the southern Meguma Terrane indicates that these aforementioned ages broadly coincide with earlier documented magmatic or tectono-thermal events (e.g., intrusion of Wedgeport Pluton at 315 Ma). Inferences by some workers of mid-Carboniferous magmatism in the Meguma Terrane are, however, not supported by the present study.