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.

Calc-silicate isograds in the Riondel area, southeastern British Columbia

1976 ◽  
Vol 13 (8) ◽  
pp. 1093-1104 ◽  
Author(s):  
Trygve Höy
Keyword(s):  
British Columbia ◽  
Regional Metamorphism ◽  
Fluid Phase ◽  
Lower Grade ◽  
Binary Fluid ◽  
Physical Conditions ◽  
Mineral Assemblages ◽  
Maximum Temperatures ◽  
Wide Zone ◽  
Model Reactions

Five metamorphic isograds have been mapped in the calc-schists of the Riondel area, British Columbia. These isograds are based on the following model reactions:[Formula: see text]The first four of these isograds represent discontinuities in the observed mineral assemblages and are located by plotting all occurrences of the complete reactant and product assemblages. The fifth isograd occurs over a wide zone in which the anorthite component of the plagioclase in the assemblage Ep–Ac–Q–Di–Pl increases with increasing metamorphic grade, from approximately An30 in the lower grade eastern part of the area to approximately An60 in the western part.The distribution of isograds and the systematic variation in plagioclase compositions in the Ep–Ac–Q–Di–Pl assemblage is modelled using [Formula: see text]diagrams that have been calculated at 5000 bars pressure under the simplifying constraint that[Formula: see text]. These diagrams provide a basis for estimating the physical conditions of regional metamorphism in the Riondel area. Maximum temperatures exceeded 600 °C in the highest grade part of the area and the composition of the hypothetical binary fluid phase varied from approximately [Formula: see text]in the lower grade to 0.5 or 0.6 in the higher grade areas.

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.

‘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.

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>

Zoned Margarite from the Badshot Formation (Cambrian) near Kaslo, British Columbia

1971 ◽  
Vol 8 (9) ◽  
pp. 1145-1147 ◽  
Author(s):  
J. W. Jones
Keyword(s):  
British Columbia ◽  
Electron Microprobe ◽  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
Regional Metamorphism ◽  
Garnet Zone

Electron microprobe analysis of margarite crystals shows that they are zoned from Ca1.13Na0.74K0.05(Al4.01Ti0.02Fe0.13Mg0.05)[Si4.78Al3.12O20](OH)4 in their centers to Ca1.63Na0.26K2.005 (Al3.98Ti0.02Fe0.13Mg0.05)[Si4.10Al3.90O20](OH)4 at their margins. The crystals occur in the disequilibrium assemblage calcite – phengite (2M1) – margarite – quartz – kaolinite – epidote –apatite found in Badshot marble from the almandine garnet zone of regional metamorphism.

Correlation Between Gestures’ Qualitative Properties and Usa- bility metrics

2020 ◽  
Vol 64 (1) ◽  
pp. 726-730
Author(s):  
Daniela Chanci ◽  
Naveen Madapana ◽  
Glebys Gonzalez ◽  
Juan Wachs
Keyword(s):  
Linear Regression ◽  
User Satisfaction ◽  
Completion Time ◽  
User Study ◽  
Task Completion ◽  
Time Error ◽  
Qualitative Properties ◽  
Regression Techniques ◽  
Overall Efficiency ◽  
Usability Metrics

The choice of best gestures and commands for touchless interfaces is a critical step that determines the user- satisfaction and overall efficiency of surgeon computer interaction. In this regard, usability metrics such as task completion time, error rate, and memorability have a long-standing as potential entities in determining the best gesture vocabulary. In addition, some previous works concerned with this problem have utilized qualitative measures to identify the best gesture. In this work, we hypothesize that there is a correlation between the qualitative properties of gestures (v) and their usability metrics (u). Therefore, we conducted an experiment with linguists to quantify the properties of the gestures. Next, a user study was conducted with surgeons, and the usability metrics were measured. Lastly, linear and non-linear regression techniques were used to find the correlations between u and v. Results show that usability metrics are correlated with the gestures’ qualitative properties ( R2 = 0.4).

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