Further Data on the Petrology of the Pelitic Hornfelses of the Carn Chuinneag–Inchbae Region, Ross-shire, with Special Reference to the Status of Almandine

1954 ◽  
Vol 91 (6) ◽  
pp. 445-462 ◽  
Author(s):  
R. I. Harker
Keyword(s):  
Special Reference ◽  
Regional Metamorphism ◽  
The Other ◽  
Contact Metamorphism ◽  
Chemical Data ◽  
Chemical Analyses ◽  
Thermal Metamorphism ◽  
Massive Structure ◽  
Mineral Assemblages ◽  
The Status

AbstractThe pelitic hornfelses surrounding the Carn Chuinneag–Inchbae complex have, with the other rocks in the area, been subjected to the regional metamorphism which affected the Moine Series as a whole. The minerals of the original hornfelses have reacted to form assemblages which are typical of regional rather than purely thermal metamorphism although the massive structure of the hornfelses is well preserved.By studying the changes which took place in the hornfelses during the regional metamorphism it has been possible to deduce the most likely mineral assemblages indigenous to the original hornfelses.The results of the chemical analyses of some of the pelitic hornfelses are presented and chemical data on some of the garnets are given. It is considered unlikely that all the garnets in the hornfelses, which are essentially almandines, formed as a result of the earlier contact metamorphism: some at least probably occur as a result of the later regional metamorphism.

Compositional variation in högbomites from north Connemara, Ireland

1985 ◽  
Vol 49 (354) ◽  
pp. 649-654 ◽  
Author(s):  
N. S. Angus ◽  
R. Middleton
Keyword(s):  
Chemical Composition ◽  
Regional Metamorphism ◽  
The Other ◽  
Partial Substitution ◽  
Compositional Variation ◽  
Physical Parameters ◽  
Chemical Heterogeneity ◽  
High Grade ◽  
Thermal Metamorphism ◽  
Mineral Assemblages

AbstractHögbomite occurs in two contrasting mineral assemblages within the Currywongaun-Dough-ruagh intrusion of north Connemara: a cordierite-rich pelitic xenolith and an orthopyroxenite. In the latter, högbomite and green spinel form blebs within magnetite-ilmenite grains. The högbomite displays significant compositional variation from grain to grain: TiO2 (3.0–6.3%), FeO (21.6–21.3%), MgO (10.0–7.5%), ZnO (3.6–2.4%). This chemical heterogeneity appears to represent variable degrees of partial substitution of Mg and Zn by Ti, in the replacement of spinel by högbomite. By contrast, in the cordierite-hornfels, the högbomite compositions are more notably enriched in iron: TiO2 (4.7–7.0%), FeO (29.6–24.3%), MgO (4.2–6.2%), ZnO (2.7–2.1%). This iron-rich högbomite appears to have formed primarily by interaction between opaque ore and adjacent cordierite, rather than by replacement of spinel.Two high-grade metamorphic episodes appear to be necessary for högbomite growth, one determining chemical composition and the other appropriate physical parameters. In the Connemara occurrences thermal metamorphism and partial melting, coupled with contamination of the surrounding magma, controlled the formation of mineral assemblages rich in Fe, Mg, Al, Ti, and Zn. Emplacement of the intrusion was accompanied by amphibolite facies regional metamorphism and it is to this metamorphic event that the growth of högbomite may be attributed.

Metamorphism of the Settler Schist, southwest of Yale, British Columbia

1976 ◽  
Vol 13 (3) ◽  
pp. 405-421 ◽  
Author(s):  
Lee C. Pigage
Keyword(s):  
British Columbia ◽  
Linear Regression ◽  
Microprobe Analysis ◽  
Regional Metamorphism ◽  
Fluid Phase ◽  
Contact Metamorphism ◽  
Major Constituent ◽  
Minor Components ◽  
Mineral Assemblages ◽  
Regression Techniques

Pelitic metasediments immediately southwest of Yale, British Columbia contain mineral assemblages characteristic of staurolite through sillimanite zones of the Barrovian facies series. Microprobe analyses of major constituent phases in the pelites are combined with linear regression techniques to formulate probable kyanite- and sillimanite-forming reactions.A zone some 3 km wide contains the assemblage staurolite–kyanite–garnet–biotite–muscovite–quartz–plagioclase-ilmenite-rutile, which is univariant in AFM projection. Within precision limits of microprobe analysis, this assemblage is also univariant using linear regression techniques. Univariant relations are possible if [Formula: see text] with the composition of the fluid phase being buffered by the progressing reaction. This assemblage emphasizes the need for precise analyses when using the regression method, since minor components are often within permissible error limits rather than being balanced.Pelitic and calc-silicate assemblages from the metasediments restrict estimates of pressure–temperature conditions during regional metamorphism to 6–8 kbar and 550–770 °C. Pseudomorphs after andalusite indicate that contact metamorphism preceded regional upgrading of the pelites.

A High-Pressure Thermal Aureole of the Bayan-Kol Gabbro–Monzodiorite Intrusion (Western Sangilen, Southeastern Tuva): Evidence for Lower-Crust Mafic Magma Chambers

2021 ◽  
Vol 62 (9) ◽  
pp. 987-1005
Author(s):  
A.Yu. Selyatitskii ◽  
O.P. Polyansky ◽  
R.A. Shelepaev
Keyword(s):  
Shear Zone ◽  
Lower Crust ◽  
Regional Metamorphism ◽  
Contact Metamorphism ◽  
Temperature Pattern ◽  
Contact Aureole ◽  
Moderate Pressure ◽  
Early Paleozoic ◽  
High Gradient ◽  
Thermal Metamorphism

Abstract —Thermal metamorphism produced an aureole near the early Paleozoic Bayan-Kol gabbro–monzodiorite intrusion in the Erzin shear zone of western Sangilen (Tuva–Mongolia microcontinent, Central Asian Orogenic Belt). Field observation of intrusive contact, structure–textural and mineral transformations of metamorphic rocks, regular changes in the chemical composition of minerals with approaching the intrusive contact, and high temperature gradient from intrusive to wallrocks verified the occurrence of a contact aureole near the Bayan-Kol intrusion. The high-gradient thermal metamorphism (M2) affected garnet–staurolite–kyanite schists that formed during earlier regional metamorphism (M1) at 6.2–7.9 kbar and 600–670 ºC. The 0.5 km wide M2 metamorphic aureole mapped along the northwestern intrusion margin consists of a muscovite–sillimanite zone adjacent to the sedimentary country rocks and a cordierite–K-feldspar zone on the side of the intrusion. The M2 metamorphic reactions occurred within the granulite facies temperature range 880–910 ºC along the contact with monzodiorites and at ~950 ºC along the boundary with gabbronorites; the temperature on the aureole periphery was about 640 ºC. Pressure estimates indicate deep-seated high-grade metamorphism at 6.9–7.8 kbar, while the intrusion itself crystallized at 7.7–7.8 kbar. The suggested numerical model implying the formation of a thermal aureole at a depth of 26 km (7 kbar) in the lower crust is consistent with the temperature pattern determined by geothermobarometry for several key points of the metamorphic zoning and confirms its deep-level origin. Thus, the aureole near the Bayan-Kol intrusion represents a rare case of contact metamorphism in the lower continental crust. The obtained results, along with published petrological and geochronological evidence, reveal two depth levels of the early Paleozoic M2 metamorphism in the Sangilen area: upper (7–15 km, 2–4 kbar) and lower (26–30 km, 7–8 kbar) crust. The Bayan-Kol gabbro–monzodiorite intrusion is likely a small apophysis or a fragment of a deep-crust intermediate magma chamber, while the moderate-pressure (7–8 kbar) M2 granulites in the Erzin shear zone are products of high-gradient metamorphism related to the Cambrian–Ordovician collisional mafic magmatism in the Sangilen area.

Dalits and Their Religious Identity in India: A Critical Look at Existing Practices

2019 ◽  
Vol 11 (2) ◽  
pp. 94-106
Author(s):  
Satri Veera Kesalu ◽  
Vukkala Srinivasulu
Keyword(s):  
Special Reference ◽  
Religious Identity ◽  
Religious Freedom ◽  
Total Population ◽  
The Other ◽  
Freedom Of Religion ◽  
Religious Intolerance ◽  
Hindu Religion ◽  
The Status ◽  
The Right

India is one of the most diversified states as far as religion is concerned. Freedom of religion in India is a fundamental right guaranteed by the Constitution. It ensures that all citizens have the right to practice and promote their religions. On the other side of the coin, there have been many incidents of religious intolerance with respect to Dalits. Since ages, Dalits have never been allowed to practice mainstream Hindu religion. Due to the lack of proper recognition in the mainstream of Hindu religion, Dalits have been adopting religions such as Christianity and Buddhism. Because of this, they are being brutally attacked by the so-called Hindu fundamentalists. As such, Dalits, who are around 20 per cent of the total population, have religious freedom in principle and lack the same in practice. In this critical game, Dalit Christians have been victimized in a greater sense. It is in this background that the article examines the constitutional obligations to offer freedom of religion in practice and the status on freedom of religion as it exists, especially with special reference to the Dalits. This article explores the incidents of religious intolerance which Dalit Christians face in India. Finally, this article summarizes, against the backdrop of some cases, the perceptions of Dalits and Dalit Christians on freedom of religion in India and their experiences.

XVI.—Metamorphism of Tertiary Lavas in Strathaird, Skye

1963 ◽  
Vol 65 (16) ◽  
pp. 413-434 ◽  
Author(s):  
D. C. Almond
Keyword(s):  
Thermal Effects ◽  
Outer Boundary ◽  
Chemical Analyses ◽  
Local Growth ◽  
Pyroclastic Rocks ◽  
Thermal Metamorphism ◽  
Eastern Margin ◽  
South Eastern ◽  
Mineral Assemblages ◽  
Metamorphic Facies

SynopsisIn Strathaird, Tertiary lavas occupy an area of about 7 square miles and are up to 1000 ft. thick. Most of the sequence consists of alkaline olivine basalts but there is also a flow of trachybasalt and a thin group of picritic lavas. Pyroclastic rocks are rare.The area lies along the south-eastern margin of the Cuillin gabbro and thermal metamorphism is evident to a varying degree over the whole of the lava outcrop. In the immediate vicinity of the gabbro the lavas have been recrystallized to pyroxene-bearing hornfelses, and these rocks are followed outwards by a broader zone characterized by the presence of actinolite, chlorite, albite and epidote. In the outermost of the three zones, which extends for at least 3 miles from the gabbro, thermal effects are limited to the local growth of chlorite, albite and epidote. When compared with Turner's (1958) scheme of metamorphic facies the inner zone is equivalent to the pyroxene hornfels and sanidinite facies whereas the two outer zones form subdivisions of the albite-epidote hornfels facies. The hornblende hornfels facies appears to be only poorly represented by a few hornfelses found on the outer boundary of the inner zone.The metamorphism was not progressive since the mineral assemblages of each zone developed independently from unmodified lavas. There is evidence that a small amount of silica was added to some of the inner zone lavas during metamorphism.Eight new chemical analyses of metamorphosed basalts are presented, together with one new analysis of a metamorphosed bole.

‘Decompressional’ reaction textures formed by isobaric heating: an example from the thermal aureole of the Taylor Brook Gabbro Complex, western Newfoundland

2002 ◽  
Vol 66 (6) ◽  
pp. 941-951 ◽  
Author(s):  
S. J. Ings ◽  
J. V. Owen
Keyword(s):  
Long Range ◽  
Regional Metamorphism ◽  
Contact Metamorphism ◽  
Contact Aureole ◽  
Mafic Intrusion ◽  
Pressure Release ◽  
Metamorphic Mineral ◽  
Mineral Assemblages ◽  
Tonalitic Gneiss ◽  
Isothermal Decompression

Abstract Reaction textures including corona structures in granulites from the Proterozoic Long Range Inlier of western Newfoundland are spatially associated with a Silurian (0.34 Ga) mafic intrusion, the Taylor Brook Gabbro Complex. They comprise, in metabasites and tonalitic gneiss, coronal orthopyroxene and plagioclase on garnet and, in metapelites, cordierite and spinel formed at the expense of sillimanite, garnet and quartz. Although generally interpreted to indicate near-isothermal decompression (ITD) following regional metamorphism, which in the inlier occurred at ˜1.10–1.03 Ga, these features appear to be absent elsewhere. Therefore they are interpreted to be products of contact metamorphism (near-isobaric heating – IBH) within the thermal aureole of the gabbro. Thus, there is a ˜0.7 Ga difference (i.e. mid-Proterozoic vs. mid-Silurian) between the age of the regional metamorphic mineral assemblages and the contact aureole assemblages. The observation that classic ITD features occur in this aureole environment underscores the fact that P-sensitive reactions can progress during IBH as well as by pressure release.

Epidiorite–limestone contact relations at Burawai, Hazara District, West Pakistan

1965 ◽  
Vol 34 (268) ◽  
pp. 82-91
Keyword(s):  
Regional Metamorphism ◽  
Thermal Metamorphism ◽  
Mineral Assemblages

SummarySpecial mineral assemblages in calcareous rocks 0–6 ft from the contact of an epidiorite sill are interpreted as the result of polymetamorphism–regional metamorphism superimposed on an earlier thermal metamorphism in which metasomatism, especially migration of potassium, was important.

Regional and Contact Metamorphism of the Dizi Series (the Greater Caucasus)

2020 ◽  
Author(s):  
Irakli Javakhishvili ◽  
Tamara Tsutsunava ◽  
David Shengelia ◽  
Giorgi Chichinadze ◽  
Giorgi Beridze
Keyword(s):  
General Scheme ◽  
Regional Metamorphism ◽  
Geological Structure ◽  
Contact Metamorphism ◽  
Maximum Temperature ◽  
Greater Caucasus ◽  
Mineral Associations ◽  
Mineral Assemblages ◽  
Characteristic Features ◽  
Composition Of Minerals

<p>The Greater Caucasus - the complex geological structure of the Caucasus is an integrated part of the Mediterranean (Alpine-Himalayan) collision orogenic belt. The Dizi series is exposed within the Greater Caucasus Southern Slope zone, in the core of Svaneti anticlinorium. It is composed of faunistically dated from the Devonian to the Triassic inclusively thin-striped and crenulated terrigenous deposits, various volcanites and marbles. Despite the well-studied stratigraphy and tectonics of the Dizi series, the issues of metamorphism, unlike the other rocks of the pre-Alpine crystalline basement of the Greater Caucasus are less studied. The rocks of the Dizi series underwent regional metamorphism of the greenschist facies chlorite-sericite sub-facies under a temperature of 300-340°С and pressures of ≈ 2-2.5 kbar. Characteristic mineral assemblages are established on the basis of microprobe analysis of chlorite, K-mica, plagioclase, actinolite, actinolitic hornblende and prehnite. Due to the contact impact of the Bathonian intrusions on the regionally metamorphosed rocks of the Dizi series, various hornfelses, spotted schists and skarns were formed. Composition of minerals of contact-metamorphism - biotite, cordierite, muscovite, plagioclase, cummingtonite, hornblende, chlorite, clinopyroxene, clinozoisite and K-feldspar is determined. According to the results of studies of key mineral assemblages of contact-metamorphosed rocks, three exocontact zones are distinguished, corresponding to the albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels sub-facies conditions. The first zone is marked by the appearance of biotite, muscovite and plagioclase of oligoclase-andesine series in metapelites; hornblende, biotite and clinozoisite in metabasites and amphibole schists; wollastonite and clinozoisite in carbonate-silicate schists. The beginning of the second zone is marked in the appearance of cordierite, corundum in metapelites and of scapolite in metabasites and carbonate-silicate schists. By the disappearance of chlorite in the metapelites, the appearance of cummingtonite in metabasites and garnet in carbonate-silicate schists, a transition to the third zone is established. In the high-temperature part of the last zone, in the metapelites fibrolite is formed. The maximum temperature in the aureole of contact metamorphism is 550⁰С, and the pressure is about 0.5-1 kbar. Due to very low pressure during the re-crystallization of rocks pyralspite garnet is missing in the mineral associations of the Dizi series rocks. Instead of garnet, the association of chlorite-quartz-muscovite appeared. Under the conditions of increasing temperature during the metamorphism a change in the characteristic features of the mineral composition is shown graphically. Based on the accessible data the authors have drawn the contact metamorphism fields on the existing general scheme of facies and subfacies of regional metamorphism.</p>

“A Study on the Influence of Rewards on Job Satisfaction With Special Reference to Education Industry in Oman”

2019 ◽  
Vol 118 (1) ◽  
pp. 114-124
Author(s):  
Mrs Nithya Sambamoorthy ◽  
Mr Subhash Kodiyil Raman ◽  
Mr Bhraguram Thayyil
Keyword(s):  
Job Satisfaction ◽  
Special Reference ◽  
Secondary Data ◽  
The Other ◽  
Primary Data ◽  
Other Hand ◽  
Education Industry ◽  
College Of Technology ◽  
Main Factors ◽  
Structured Questionnaire

This research is an examination and a study on the influence of rewards on job satisfaction of lecturers at Shinas College of Technology (ShCT). In academic industry, rewards are one of the factors that affecting job satisfaction of the employees and this will lead to affect their performance in their jobs. So, when rewards are more the job satisfaction will be high and when rewards are less the job satisfaction will be less. On the other hand, the age will not affect the job satisfaction. Previous research reveals that Job satisfaction is very important to success the industry and the rewards are the main factors which affect job satisfaction. The main purpose of this study is to know the influence of rewards in job satisfaction among the lecturers in ShCT. Moreover, this research attempts to identify how much rewards affect the job satisfaction in ShCT.  For this study used two types of data which are: primary data and secondary data. The sources of primary data is the response from lecturers at ShCT. It is collected through structured questionnaire and distributed such to 60 respondents. Secondary data, collected from internet, books, journals, articles etc.

Status of Family Fissidentaceae in Gujarat

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar
Keyword(s):  
Distinct Species ◽  
The State ◽  
The Other ◽  
Land Plants ◽  
Reproductive Structures ◽  
The Family ◽  
The Status ◽  
Vegetative Characters ◽  
First Time ◽  
Different Parts

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.

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