scholarly journals Methanogenesis Potentials: Insights from Mineralogical Diagenesis, SEM and FTIR Features of the Permian Mikambeni Shale of the Tuli Basin, Limpopo Province of South Africa

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 651
Author(s):  
George Oluwole Akintola ◽  
Francis Amponsah-Dacosta ◽  
Steven Rupprecht ◽  
Nithyadharseni Palaniyandy ◽  
Sphiwe Emmanuel Mhlongo ◽  
...  
Keyword(s):  
Absorption Band ◽  
Reaction Pathway ◽  
Limpopo Province ◽  
Carbonaceous Shale ◽  
Burial Depth ◽  
Low Grade ◽  
Microbial Activities ◽  
Replacement Reaction ◽  
Strong Absorption Band ◽  
Shale Formations

Carbonaceous shale is more topical than ever before due to the associated unconventional resources of methane. The use of FTIR, SEM-EDX, and mineralogical analyses has demonstrated a promising approach to assess methanogenesis potentials in a more rapid and reliable manner for preliminary prospecting. Representative core samples from the borehole that penetrated the carbonaceous Mikambeni shale Formations were investigated for methanogenesis potentials. The absorption band stretches from 1650 cm−1 to 1220 cm−1 in wavenumber, corresponding to C-O stretching and OH deformation of acetic and phenolic groups in all studied samples, thereby suggesting biogenic methanogenesis. The CO2 was produced by decarboxylation of organic matter around 2000 cm−1 and 2300 cm−1 and served as a source of the carboxylic acid that dissolved the feldspar. This dissolution process tended to release K+ ions, which facilitated the illitization of the smectite minerals. The SEM-EDX spectroscopy depicted a polyframboidal pyrite structure, which indicated a sulfate reduction of pyrite minerals resulting from microbial activities in an anoxic milieu and causes an increase in alkalinity medium that favors precipitation of dolomite in the presence of Ca and Mg as burial depth increases. The contact diagenesis from the proximity of Sagole geothermal spring via Tshipise fault is suggested to have enhanced the transformation of smectite to chlorite via a mixed layer corrensite in a solid-state gradual replacement reaction pathway. The presence of diagenetic chlorite mineral is characteristic of low-grade metamorphism or high diagenetic zone at a temperature around 200 °C to 230 °C and corresponds to thermal breakdown of kerogen to methane at strong absorption band around 2850 cm−1 and 3000 cm−1, indicating thermal methanogenesis.

scholarly journals ON THE INFRARED ABSORPTION OF WATER AND HEAVY WATER IN CONDENSED STATES

1956 ◽  
Vol 34 (6) ◽  
pp. 798-808 ◽  
Author(s):  
Paul A. Giguère ◽  
K. B. Harvey
Keyword(s):  
Thin Films ◽  
Absorption Band ◽  
Water Molecule ◽  
Air Temperature ◽  
Heavy Water ◽  
Infrared Spectra ◽  
Infrared Absorption ◽  
Silver Chloride ◽  
Strong Absorption Band ◽  
Librational Mode

The infrared spectra (from 2 to 30 μ) of thin films of H2O and D2O were measured at various temperatures between 20 ° and −180 °C. A strong absorption band due to the librational mode of the water molecule has its maximum around 710 cm.−1 in the liquid. In ice it is shifted to 800 cm.−1 at −15 °C. and 850 cm.−1 at −170 °C. The corresponding D2O bands show the normal isotope shift. Thin films of water pressed between silver chloride plates could not be crystallized even at liquid air temperature as confirmed by their spectra, which were almost identical with those of the liquid.

Clay mineral variations associated with diagenesis and low-grade metamorphism of Early Cretaceous sediments in the Cameros Basin, Spain

Clay Minerals ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 119-133 ◽  
Author(s):  
J. F. Barrenechea ◽  
M. Rodas ◽  
J. R. Mas
Keyword(s):  
Clay Mineral ◽  
Early Cretaceous ◽  
Sudden Change ◽  
Burial Depth ◽  
Low Grade ◽  
Depositional Sequence ◽  
Depositional Sequences ◽  
Mineral Assemblages ◽  
Cameros Basin ◽  
Main Factor

AbstractThe clay mineral distribution in the Early Cretaceous depositional sequences along the Cameros Basin has been established on the basis of XRD traces and TEM/EDAX analyses. Samples from the Latest Berriasian-Barremian depositional sequences are characteristic of epimetamorphic conditions. Illite ‘crystallinities’ are broader than expected (0.35–0.490°Δ2θ), due to the consistent presence of K-mica-paragonite mixed-layer and discrete paragonite associated with the illite 10 Å peak. The Late Barremian-Early Aptian depositional sequence, around the depocentral sector of the basin, represents a sudden change to anchimetamorphic conditions, marked by the presence of pyrophyllite and rectorite and by a significant decrease in the A1IV content of the chlorites. Towards the northwestern border of the basin, this sequence was affected by deep diagenetic conditions, as deduced from the clay mineral association and the ‘crystallinity’ values (0.57°Δ2θ). The changes in the clay mineral assemblages and ‘crystallinity’ data can hardly be explained in terms of the varying burial depth and are related to changes in the circulation of fluids associated with varying facies (modal composition, grain size). Permeability is regarded as the main factor controlling the circulation of these migratory fluids.

scholarly journals Rhabdophane Th-Pb ages indicate reactivation of Mesoarchean structures in west Pilbara Craton during breakup of Greater India and Australia-Antarctica

Geology ◽  
2021 ◽  
Author(s):  
Birger Rasmussen ◽  
Jian-Wei Zi ◽  
Janet R. Muhling
Keyword(s):  
Fluid Flow ◽  
Shear Zones ◽  
Drill Hole ◽  
Carbonaceous Shale ◽  
Low Grade ◽  
Early Environment ◽  
Metasedimentary Rocks ◽  
Rift Propagation ◽  
History Of ◽  
Pilbara Craton

Uranium-Th-Pb dating of phosphate minerals in very low-grade metasedimentary rocks from the Archean Pilbara Craton, Western Australia, has revealed a long history of deformation and fluid flow during the Paleoproterozoic. However, this technique has not detected evidence for fluid flow along craton margins during Phanerozoic rifting and breakup. We report the use of in situ Th-Pb geochronology of rhabdophane, a hydrous light rare earth element phosphate, to date fluid flow in shale from the 2.76 Ga Mount Roe Basalt from drill hole number 6 of the Archean Biosphere Drilling Program (ABDP6), northwestern Pilbara Craton. Thorium-Pb dating of rhabdophane in carbonaceous shale yields three main populations with weighted mean 208Pb/232Th ages of 152 ± 6 Ma, 132 ± 4 Ma, and 119 ± 4 Ma, which indicates phosphate growth up to 2.64 b.y. after deposition. The rhabdophane ages are coeval with three major breakup events in eastern Gondwana: separation of Southwest Borneo and Argoland from Australia (ca. 156–152 Ma), breakup of Greater India from Australia (ca. 140–135 Ma), and separation of Greater India/India from Antarctica (ca. 123 Ma). The proximity of drill hole ABDP6 to major Mesoarchean faults and shear zones on the craton margin, which are parallel to rift propagation and basin development, points to episodic reactivation of ancient crustal structures >2.8 b.y. after their formation. Our results also highlight the potential of rhabdophane as a U-Th-Pb geochronometer for dating low-temperature (<200 °C) fluid flow and hydrous alteration. The migration of Mesozoic fluids through Archean shales adds weight to questions about the origin of geochemical signals in ancient altered rocks and how to extract information about the early environment and biosphere.

Comparative study of the transition between very low-grade and low-grade metamorphism in siliciclastic and carbonate sediments: Early Cretaceous, Cameros Basin (northern Spain)

Clay Minerals ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 407-419 ◽  
Author(s):  
J. Alonso-Azcarate ◽  
J. F. Barrenechea ◽  
M. Rodas ◽  
J. R. Mas
Keyword(s):  
Early Cretaceous ◽  
Burial Depth ◽  
Low Grade ◽  
Carbonate Sediments ◽  
Northern Spain ◽  
Grade Metamorphism ◽  
Mineral Assemblages ◽  
Great Heterogeneity ◽  
Cameros Basin ◽  
Facies Types

AbstractThe transition between very low-grade and low-grade metamorphism has been studied in the Urbión and Enciso Groups of the Late Jurassic-Early Cretaceous Cameros basin (NE Spain). The ‘illite crystallinity’ (IC) values do not appear to be controlled by burial depth but rather by: (1) XRD overlap with other phases (e.g. paragonite and mixed-layered muscovite-paragonite) in the siliciclastic samples; (2) the presence of carbonates, which delay illitization, resulting in an increase in the IC values, that becomes more pronounced as the P-T conditions decrease towards the diagenesis zone; and (3) the permeability of the sediments, which controls the circulation of metamorphic fluids and therefore the distribution of ‘crystallinities’ and mineral assemblages within the basin.The anchizone is represented by a narrow range of ‘chlorite crystallinity’ (ChC) values. Therefore, ChC is a less sensitive parameter than IC for estimating changes from diagenetic to low-grade metamorphic conditions. However, ChC can be a useful tool when there is a great heterogeneity of facies types, as it is not affected by the presence of carbonates.

Nitrogenous chelate complexes of transition metals. VII. Complexes of silver(I) and silver(II) with tridentate chelating ligands

1970 ◽  
Vol 23 (6) ◽  
pp. 1125 ◽  
Author(s):  
CM Harris ◽  
TN Lockyer
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Absorption Band ◽  
Magnetic Moments ◽  
Chelating Ligands ◽  
Chelate Complexes ◽  
Complex Ions ◽  
Strong Absorption Band ◽  
Stable Species ◽  
Complexes Of Transition Metals

Silver(1) complexes of 2,2',2"-terpyridine and a related Schiff base chelate 8-(or-pyridylmethyleneamino)quinoline have been prepared. They are of the type Ag(chelate)X, where X = NO3, ClO4, and PF6. Both Ag(terpy)+ and Ag(pmq)+ are stable in solution and conductance measurements have been obtained. Ag(terpy)PF6 is monomeric in nitrobenzene. Reaction of the above complex ions with pyridine or triphenylphosphine affords stable species of the form [Ag(chelate)(py)]+ and [Ag(chelate)(Ph3P)]+ which have been isolated as their perchlorate salts. Both Ag(chelate)+ and [Ag(ohelate)L]+ involve unusual stereochemistry for AgI. The known paramagnetic AgII complexes Ag(terpy)X2 (X = NO3, ClO4, �S2O8) have been reprepared. They are unstable in solution and reduce readily to AgI. They all show magnetic moments in the range 1.7-1.9 B.M. Ag(terpy)2+ in an aqueous solution of CeIv shows a strong absorption band at 470 mμ (880).

Smoky, blue, greenish yellow, and other irradiation-related colors in quartz

1977 ◽  
Vol 41 (319) ◽  
pp. 301-312 ◽  
Author(s):  
K. Nassau ◽  
B. E. Prescott
Keyword(s):  
Absorption Band ◽  
Absorption Spectroscopy ◽  
Fused Silica ◽  
Blue Color ◽  
Strong Absorption Band ◽  
Synthetic Quartz ◽  
Low Intensity ◽  
Greenish Yellow ◽  
Absorption Features ◽  
Natural And Synthetic

SummaryAlmost 400 specimens of natural and synthetic quartz were γ-irradiated and then heated. Polarized absorption spectroscopy, EPR, and spectrochemical analysis were used to investigate the various colors produced.A blue color originated from absorption by the A1 and A2 bands at 1·85 and 2·55 eV. The substitutional A1 EPR hole-type center usually considered to be the cause of the color in smoky quartz does not correlate with A1 and A2, but with A3, a previously unreported absorption band at 2·90 eV. The A1 and A2 absorptions bleach at temperatures as low as 280 °C and as high as 360 °C the range for A3 being 140 to 380 °C. The B band at 3·95 eV was previously reported only in irradiated fused silica.Greenish-yellow colors (appearing yellow when of low intensity) were observed after irradiation (followed by heating in some instances) in many specimens of natural and synthetic quartz; the color originates from the tail of a strong absorption band in the ultraviolet. The bleaching temperature range is the same as that for A2.The wide variation in color of natural and irradiated smoky quartz can be explained by combinations of the smoky (A3), blue (A1 and A2), and greenish yellow absorption features.

Optical Absorption Spectra of Phosphonyl Radicals

1984 ◽  
Vol 39 (5) ◽  
pp. 434-436 ◽  
Author(s):  
T. Sumiyoshi ◽  
A. Henne ◽  
P. Lechtken ◽  
W. Schnabel
Keyword(s):  
Free Radicals ◽  
Absorption Band ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
General Structure ◽  
Laser Flash ◽  
Type I ◽  
Phosphine Oxides ◽  
Optical Absorption Spectra ◽  
Strong Absorption Band

Upon UV-irradiation, various phosphine oxides of the general structure I were found to be fragmented readily into free radicals I′ and I″ Laser flash photolysis studies revealed that radicals of type I" with R2 and/or R3 being phenyl groups possess a strong absorption band with a maximum around 330 nm. ε335nm= 1.9×104 1/mol cm was estimated for diphenyl phosphonyl radicals (Ph2P = O).

Expanding the strong absorption band by impedance matched mosquito-coil-like acoustic metamaterials

2020 ◽  
Vol 91 (2) ◽  
pp. 025102
Author(s):  
Mingming Hou ◽  
Junxiang Wu ◽  
Shaokun Yang ◽  
Jiu Hui Wu ◽  
Fuyin Ma
Keyword(s):  
Absorption Band ◽  
Strong Absorption ◽  
Acoustic Metamaterials ◽  
Mosquito Coil ◽  
Strong Absorption Band

Rational design of a main chain conjugated copolymer having donor–acceptor heterojunctions and its application in indoor photovoltaic cells

2020 ◽  
Vol 8 (38) ◽  
pp. 20091-20100
Author(s):  
Na Yeon Kwon ◽  
Su Hong Park ◽  
Hungu Kang ◽  
Ashkan Vakilipour Takaloo ◽  
Amit Kumar Harit ◽  
...  
Keyword(s):  
Absorption Band ◽  
High Power ◽  
Rational Design ◽  
Main Chain ◽  
Power Conversion ◽  
Photovoltaic Cells ◽  
High Power Conversion Efficiency ◽  
Strong Absorption Band ◽  
Donor Acceptor ◽  
Conjugated Copolymer

P(BDBT-co-NDI2T) exhibited a strong absorption band, which overlapped with the emission spectrum of an LED lamp and it exhibited a high power conversion efficiency of 12.70% under the LED lamp (@500 lux).

scholarly journals Observation of precursorlike behavior of femtosecond pulses in a dye with a strong absorption band

2011 ◽  
Vol 83 (4) ◽  
Author(s):  
Matthew M. Springer ◽  
Wenlong Yang ◽  
Alexandre A. Kolomenski ◽  
Hans A. Schuessler ◽  
James Strohaber ◽  
...  
Keyword(s):  
Absorption Band ◽  
Strong Absorption ◽  
Femtosecond Pulses ◽  
Strong Absorption Band
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