scholarly journals A new approach to develop the R aman carbonaceous material geothermometer for low‐grade metamorphism using peak width

Island Arc ◽  
2013 ◽  
Vol 23 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Yui Kouketsu ◽  
Tomoyuki Mizukami ◽  
Hiroshi Mori ◽  
Shunsuke Endo ◽  
Mutsuki Aoya ◽  
...  
Keyword(s):  
Carbonaceous Material ◽  
Low Grade ◽  
Peak Width ◽  
New Approach ◽  
Grade Metamorphism

Strain localization mechanism of graphitic carbon-bearing rocks: Constraints from microstructure, texture and graphite geothermometry

2021 ◽  
Author(s):  
Meixia Lyu ◽  
Shuyun Cao
Keyword(s):  
Shear Zone ◽  
Strain Localization ◽  
Carbonaceous Material ◽  
Shear Zones ◽  
Graphitic Carbon ◽  
Maximum Temperature ◽  
Low Grade ◽  
High Grade ◽  
Grade Metamorphism ◽  
Average Temperature

<p><strong>Abstracts:</strong></p><p>Graphitic carbon-bearing rocks can occur in low- to high-grade metamorphic units. In low-grade matamorphic rocks, graphitic carbon is often associated with brittle fault gouge whereas in middle- to high-grade metamorphic rocks, graphitic carbon commonly occurs in marble, schist or paragneiss. Previous studies showed that carbonaceous material gradually ordered from the amorphous stage, e.g. graphitization, is mainly controlled by increasing thermal metamorphism and has a good correlation with the metamorphic temperature. Besides, this ordered process is irreversible and the resulting structure is not affected by late metamorphism. Subsequently, the degree of graphitization is believed to be a reliable indicator of peak temperature conditions in the metamorphic rock. In this contribution, based on detailed field observations, the variably deformed and metamorphosed graphitic gneisses to phyllites, located within the footwall and hanging-walls unit of the Cenozoic Ailaoshan-Red River strike-slip shear zone are studied. According to lithological features and temperature determined by Raman spectra of carbonaceous material, these graphitic rocks and deformation fabrics are divided into three types. Type I is represented by medium–grade metamorphism and strongly deformed rocks with an average temperature of 509 °C and a maximum temperature of 604 °C. Type II is affected by low-grade metamorphism and deformed rocks with an average temperature of 420 °C. Type III is affected by lower–grade metamorphism and occurs in weakly deformed/undeformed rocks with an average temperature of 350 °C. Slip–localized micro–shear zone and laterally continuous or discontinuous slip planes constituted by graphitic carbon aggregates are developed in Types I and II. The electron back–scattered diffraction (EBSD) lattice preferred orientation (LPO) patterns of graphitic carbon grains were firstly observed in comparison with LPO patterns of quartz and switch from basal <a>, rhomb <a> to prism <a> slip systems, which indicate increasing deformation temperatures. According to the graphitic slip–planes, micro–shear zones and mylonitic foliation constituted by graphitic carbon minerals, we also propose that the development of fine–grained amorphous carbon plays an important role in rheological weakening of the whole rock during progressive ductile shearing.</p><p><strong>Key Words:</strong> graphitic carbon, strain localization, graphitic thermometry, slip–localized micro–shear zone, rheological weakening</p>

scholarly journals Progressive Low-Grade Metamorphism Reconstructed from the Raman Spectroscopy of Carbonaceous Material and an EBSD Analysis of Quartz in the Sanbagawa Metamorphic Event, Central Japan

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 854
Author(s):  
Hidetoshi Hara ◽  
Hiroshi Mori ◽  
Kohei Tominaga ◽  
Yuki Nobe
Keyword(s):  
Raman Spectroscopy ◽  
Carbonaceous Material ◽  
Metamorphic Event ◽  
Ebsd Analysis ◽  
Low Grade ◽  
Accretionary Complex ◽  
Metamorphic Complex ◽  
Central Japan ◽  
Grade Metamorphism ◽  
Quartz Grains

Low-grade metamorphic temperature conditions associated with the Sanbagawa metamorphic event were estimated by the Raman spectroscopy of carbonaceous material (RSCM) in pelitic rocks and an electron backscatter diffraction (EBSD) analysis of the quartz in siliceous rocks. Analytical samples were collected from the Sanbagawa metamorphic complex, the Mikabu greenstones, and the Chichibu accretionary complex in the eastern Kanto Mountains, central Japan. Previously, low-grade Sanbagawa metamorphism was only broadly recognized as pumpellyite–actinolite facies assigned to the chlorite zone. The RSCM results indicate metamorphic temperatures of 358 °C and 368 °C for the chlorite zone and 387 °C for the garnet zone of the Sanbagawa metamorphic complex, 315 °C for the Mikabu greenstones, and 234–266 °C for the Chichibu accretionary complex. From the EBSD analyses, the diameter of the quartz grains calculated by the root mean square (RMS) approximation ranges from 55.9 to 69.0 μm for the Sanbagawa metamorphic complex, 9.5 to 23.5 μm for the Mikabu greenstones, and 2.9 to 7.3 μm for the Chichibu accretionary complex. The opening angles of the c-axis fabric approximate 40–50°, presenting temperatures of 324–393 °C for the Sanbagawa metamorphic complex and the Mikabu greenstones. The temperature conditions show a continuous increase with no apparent gaps from these low-grade metamorphosed rocks. In addition, there exists an empirical exponential relationship between the estimated metamorphic temperatures and the RMS values of the quartz grains. In this study, integrated analyses of multiple rock types provided valuable information on progressive low-grade metamorphism and a similar approach may be applied to study other metamorphic complexes.

Albitized microcline grains of post-depositional and probable detrital origins in Brøttum Formation sandstones (Upper Proterozoic), Sparagmite Region of southern Norway

1988 ◽  
Vol 125 (3) ◽  
pp. 229-239 ◽  
Author(s):  
S. Morad
Keyword(s):  
Carbonaceous Material ◽  
Low Grade ◽  
Grade Metamorphism ◽  
Upper Proterozoic ◽  
Southern Norway

AbstractUntwinned albite (Ab99.4An0.4Or0.2) grains, forming during diagenesis and very low-grade metamorphism, are common in sandstones of the Brøttum Formation (Upper Proterozoic) in the Sparagmite Region of southern Norway. These untwinned albite grains are usually clouded by vacuoles and tiny inclusions which are mostly made of carbonaceous material (although some albite grains also contain some combination of carbonates, quartz, phengite, chlorite, pyrite, halite and anatase). The presence of microcline grains replaced partly by albite indicates that the albite grains are pseudomorphs after microcline. Chessboard albite which occurs in the Brøttum Formation is suggested to be detrital in origin.

Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

1977 ◽  
Vol 35 ◽  
pp. 162-163
Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck
Keyword(s):  
Crystallite Size ◽  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Low Grade ◽  
X Ray ◽  
Graphitized Carbon ◽  
Transmission Electron ◽  
Heat Treated ◽  
Commercial Carbon ◽  
Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

Low-grade metamorphism and accretion tectonics: Southern Uplands terrain, Scotland

1985 ◽  
Vol 49 (352) ◽  
pp. 335-344 ◽  
Author(s):  
A. E. S. Kemp ◽  
G. H. J. Oliver ◽  
J. R. Baldwin
Keyword(s):  
Subduction Zones ◽  
Structural Data ◽  
Low Grade ◽  
Structural Level ◽  
Concomitant Increase ◽  
Illite Crystallinity ◽  
Grade Metamorphism ◽  
Trench Slope ◽  
Reflectance Data ◽  
Trajectory Characteristic

AbstractPrevious studies of low-grade metamorphism in the Southern Uplands accretionary terrain indicated prehnite-pumpellyite facies/anchizone conditions developed throughout the area, except for local preservation of trench-slope sediments and an accreted seamount at zeolite facies/advanced diagenetic grade. New graptolite reflectance data are presented that show a general northward increase in temperature in the Southern Uplands. The results from two cross-strike traverses in the southern and central belts in contemporaneous sequences, using illite crystallinity, illite lateral spacing (bo) , and graptolite reflectance, indicate the development of systematic accretion-related low-grade metamorphism. Well-developed and constant anchizone conditions occur throughout the NE (Langholm) traverse, associated with common, F1 accretion-related folding and a regionally penetrative S1 cleavage. In the SW (Kirkcudbright) traverse, however, the youngest, last accreted packets are preserved at a transitional diagenetic stage and lack a penetrative S1 cleavage. Illite crystallinity, graptolite reflectance, and bo increase systematically northward through earlier accreted packets, reaching values of the NE traverse only at the northern end. The concomitant increase of bo with illite crystallinity suggests the relatively high P-low T trajectory characteristic of subduction zones. Integration of metamorphic and structural data relates increasing intensity of aceretion-related F1 folding, developmertt of S1 fabric, and onset of later fold phases to grade of metamorphism and structural level within the accretionary pile.

scholarly journals Rolling membrane powered by low-temperature steam as a new approach to generate mechanical energy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chongshan Yin ◽  
Qicheng Liu ◽  
Qing Liu
Keyword(s):  
Water Vapor ◽  
Low Temperature ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Heat Energy ◽  
Steam Engine ◽  
Low Grade ◽  
Human Society ◽  
New Approach ◽  
Low Grade Heat

Abstract How to convert heat energy into other forms of usable energy more efficiently is always crucial for our human society. In traditional heat engines, such as the steam engine and the internal combustion engine, high-grade heat energy can be easily converted into mechanical energy, while a large amount of low-grade heat energy is usually wasted owing to its disadvantage in the temperature level. In this work, for the first time, the generation of mechanical energy from both high- and low-temperature steam is implemented by a hydrophilic polymer membrane. When exposed to water vapor with a temperature ranging from 50 to 100 °C, the membrane repeats rolling from one side to another. In nature, this continuously rolling of membrane is powered by the steam, like a miniaturized “steam engine”. The differential concentration of water vapor (steam) on the two sides of the membrane generates the asymmetric swelling, the curve, and the rolling of the membrane. In particular, results suggest that this membrane based “steam engine” can be powered by the steam with a relatively very low temperature of 50 °C, which indicates a new approach to make use of both the high- and low-temperature heat energy.

Neodymium and strontium isotopic dating of diagenesis and low-grade metamorphism of argillaceous sediments

1994 ◽  
Vol 58 (5) ◽  
pp. 1471-1481 ◽  
Author(s):  
Urs Schaltegger ◽  
Peter Stille ◽  
Naoual Rais ◽  
Alain Piqué ◽  
Norbert Clauer
Keyword(s):  
Low Grade ◽  
Isotopic Dating ◽  
Grade Metamorphism
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