Synchrotron FTIR imaging of OH in quartz mylonites

Abstract. Previous measurements of water in deformed quartzites using conventional Fourier transform infrared spectroscopy (FTIR) instruments have shown that water contents of larger grains vary from one grain to another. However, the non-equilibrium variations in water content between neighboring grains and within quartz grains cannot be interrogated further without greater measurement resolution, nor can water contents be measured in finely recrystallized grains without including absorption bands due to fluid inclusions, films, and secondary minerals at grain boundaries.Synchrotron infrared (IR) radiation coupled to a FTIR spectrometer has allowed us to distinguish and measure OH bands due to fluid inclusions, hydrogen point defects, and secondary hydrous mineral inclusions through an aperture of 10 µm for specimens > 40 µm thick. Doubly polished infrared (IR) plates can be prepared with thicknesses down to 4–8 µm, but measurement of small OH bands is currently limited by strong interference fringes for samples < 25 µm thick, precluding measurements of water within individual, finely recrystallized grains. By translating specimens under the 10 µm IR beam by steps of 10 to 50 µm, using a software-controlled x − y stage, spectra have been collected over specimen areas of nearly 4.5 mm2. This technique allowed us to separate and quantify broad OH bands due to fluid inclusions in quartz and OH bands due to micas and map their distributions in quartzites from the Moine Thrust (Scotland) and Main Central Thrust (Himalayas).Mylonitic quartzites deformed under greenschist facies conditions in the footwall to the Moine Thrust (MT) exhibit a large and variable 3400 cm−1 OH absorption band due to molecular water, and maps of water content corresponding to fluid inclusions show that inclusion densities correlate with deformation and recrystallization microstructures. Quartz grains of mylonitic orthogneisses and paragneisses deformed under amphibolite conditions in the hanging wall to the Main Central Thrust (MCT) exhibit smaller broad OH bands, and spectra are dominated by sharp bands at 3595 to 3379 cm−1 due to hydrogen point defects that appear to have uniform, equilibrium concentrations in the driest samples. The broad OH band at 3400 cm−1 in these rocks is much less common. The variable water concentrations of MT quartzites and lack of detectable water in highly sheared MCT mylonites challenge our understanding of quartz rheology. However, where water absorption bands can be detected and compared with deformation microstructures, OH concentration maps provide information on the histories of deformation and recovery, evidence for the introduction and loss of fluid inclusions, and water weakening processes.

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Synchrotron FTIR imaging of OH in quartz mylonites

10.5194/se-2017-23 ◽

2017 ◽

Author(s):

Andreas K. Kronenberg ◽

Hasnor F. B. Hasnan ◽

Caleb W. Holyoke III ◽

Richard D. Law ◽

Zhenxian Liu ◽

...

Keyword(s):

Fluid Inclusions ◽

Light Sources ◽

Main Central Thrust ◽

Absorption Bands ◽

Hydrous Mineral ◽

Ir Radiation ◽

Mineral Inclusions ◽

Measurement Resolution ◽

Quartz Grains ◽

Water Contents

Abstract. Methods of measuring OH absorption bands of fluid inclusions and hydrogen defects in deformed quartz rocks at high spatial resolution are described, using synchrotron infrared IR radiation coupled with a Fourier transform infrared FTIR microscope, and applied to imaging OH in mylonites of the Moine Thrust (from the Stack of Glencoul, NW Scotland Caledonides) and the Main Central Thrust (from the Himalayan front, Sutlej Valley, NW India). Previous measurements of water in deformed quartzites using conventional FTIR instruments, through apertures of 50–100 μm for specimens ~ 100 μm in thickness have shown that water contents of larger grains vary from one grain to another. However, the non-equilibrium variations in water content between neighboring grains and within quartz grains cannot be interrogated further without greater measurement resolution, nor can water contents be measured in finely recrystallized grains without including absorption bands due to fluid inclusions, films, and secondary minerals at grain boundaries. Synchrotron IR radiation is brighter and more collimated than offered by conventional FTIR globar light sources, and we have been able to distinguish and measure OH bands due to fluid inclusions, hydrogen point defects, and secondary hydrous mineral inclusions through an aperture of 10 μm for specimens > 40 μm thick. Doubly polished IR plates can be prepared with thicknesses down to 4–8 μm, but measurement of small OH bands is currently limited by strong interference fringes for samples

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Water transport by subduction: Clues from garnet of Erzgebirge UHP eclogite

American Mineralogist ◽

10.2138/am-2017-5920 ◽

2017 ◽

Vol 102 (5) ◽

pp. 975-986 ◽

Cited By ~ 8

Author(s):

Esther Schmädicke ◽

Jürgen Gose

Keyword(s):

Water Transport ◽

Fluid Inclusions ◽

Hanging Wall ◽

Ultrahigh Pressure ◽

Molecular Water ◽

Structural Water ◽

Hydrous Minerals ◽

Calcic Amphibole ◽

Eclogite Facies ◽

Water Contents

Abstract A key question concerning the water budget of Earth’s mantle is how much water is actually recycled into the mantle by the subduction of eclogitized oceanic crust. Hydrous phases are stable only in quartz eclogite not coesite eclogite so that water transport to greater depths is mainly governed by structural water in omphacite and garnet. Here we explore if garnet can be used as a proxy to assess the amount of this water. Available data on the water contents of garnet in coesite eclogite vary over orders of magnitude, from a few up to ca. 2000 ppm. By implication, the maximum bulk-rock water contents are unrealistically high (wt% level). New data from the Erzgebirge indicate moderate amounts of structural H2O stored in garnet (43–84 ppm), omphacite (400–820 ppm), and in the bulk coesite eclogite (ca. 280–460 ppm). Higher garnet water contents occur, but these are not primary features. They are related to molecular water in fluid inclusions that can be attributed to eclogite-facies fluid influx postdating the metamorphic peak. Fluid influx also caused the uptake of additional structural water in garnet domains close to fluid inclusions. Such secondary H2O incorporation is only possible in the case of primary water-deficiency indicating that garnet hosted less water than it was able to store. This is insofar astonishing as comparably high H2O amounts are liberated by the breakdown of prograde eclogite-facies hydrous minerals as a result of ultrahigh-pressure (UHP) metamorphism. Judging from Erzgebirge quartz eclogite, dehydration of 5–10% hydrous minerals (±equal portions of zoisite+calcic amphibole) produces 1500–3000 ppm water. We infer that the largest part of the liberated water escaped, probably due to kinetic reasons, and hydrated exhuming UHP slices in the hanging-wall. Depending on the physical conditions, water influx in eclogite during exhumation (1) produces fluid inclusions and simultaneously enhances the structural water content of nominally anhydrous minerals—as in the Erzgebirge—and/or (2) it may give rise to retrograde hydrous minerals. We conclude that eclogite transports moderate quantities of water (several hundred parts per million) to mantle depths beyond 100 km, an amount equivalent to that in ca. 1% calcic amphibole.

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Strength of dry and wet quartz in the low–temperature plasticity regime: insights from nanoindentation

10.5194/egusphere-egu21-14625 ◽

2021 ◽

Author(s):

Luca Menegon ◽

Alberto Ceccato ◽

Lars N. Hansen

Keyword(s):

Low Temperature ◽

Water Content ◽

Crystallographic Orientation ◽

Secondary Ion Mass Spectrometry ◽

High Stress ◽

Peierls Stress ◽

Strain History ◽

Synthetic Quartz ◽

Quartz Grains ◽

Water Contents

The strength of experimentally deformed natural and synthetic quartz is strongly affected by the intracrystalline water content. Water&#8211;related defects weaken quartz by either decreasing the resistance to dislocation motion (Peierls stress) or by enhancing the nucleation of dislocations, during what is commonly referred to as hydrolytic weakening. However, hydrolytic weakening has been observed predominantly in synthetic quartz grains, with water contents higher than 20&#8211;30 wt ppm H2O and at high-homologous temperatures, for which the activation of dislocation climb and recovery processes is enhanced.In the low-temperature plasticity (LTP) regime, at low-homologous temperatures and high stress conditions, quartz plasticity is mainly controlled by dislocation glide. At these conditions, the possible effect of intracrystalline water on quartz strength is still a matter of debate.In order to analyse the effects of intracrystalline water content on the plastic yield and hardness of quartz in the LTP regime, natural samples from recrystallized quartz domains of a granulite-facies migmatitic gneiss, presenting different water contents and microstructures, have been investigated through a series of spherical and Berkovich nanoindentation tests at room conditions. Nanoindentation tests have been integrated with measurements of intracrystalline water contents of the indented grains with secondary ion-mass spectrometry (SIMS), and with electron backscatter diffraction (EBSD) measurements of the crystallographic orientation of the indented grains.Water content of indented quartz grains ranges between 2 and 104 wt ppm H2O. Samples and related nanoindentation tests were thus classified as either &#8220;dry&#8221; (DQ, for water contents < 20 wt ppm H2O) or &#8220;wet&#8221; (WQ, for water content > 20 wt ppm H2O). Spherical nanoindentation tests revealed comparable yield stresses (ranging between 3.5 and 8.8 GPa, depending on the crystal orientation) for DQ and WQ grains. In addition, significant strain hardening was observed in both DQ and WQ grains. Berkovich nanoindentation tests also resulted in comparable hardness (ranging from 8.0 to 13.5 GPa) in both DQ and WQ grains. The hardness also increases with indentation depth, which is consistent with the &#8220;size-effect&#8221; on mineral strength during LTP.These results suggest that, for the investigated range of water contents, the yield strength and flow stress of quartz in the LTP regime is not affected by the intracrystalline water content of the indented grain. Both the dry and wet quartz experienced significant crystal plastic deformation prior to the nanoindentation tests, as evidenced by the occurrence of undulatory extinction, misorientation bands, subgrains, and recrystallized grains. This pre-indentation strain history may have had a major role in generating the dislocation density, which then controlled the yield stresses during low-temperature plasticity in our experiments. Hence, inherited strain history, crystallographic orientation, and grain size may play a more important role than water in controlling the strength of the continental crust at the brittle&#8211;ductile transition, where LTP is dominant and quartz is the most abundant phase.

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Water loss during dynamic recrystallization of Moine thrust quartzites, northwest Scotland

Geology ◽

10.1130/g47041.1 ◽

2020 ◽

Vol 48 (6) ◽

pp. 557-561

Author(s):

Andreas K. Kronenberg ◽

Kyle T. Ashley ◽

Matthew K. Francsis ◽

Caleb W. Holyoke III ◽

Lynna Jezek ◽

...

Keyword(s):

Grain Boundary ◽

Water Content ◽

Water Concentration ◽

Inverse Correlation ◽

High Water ◽

Dislocation Creep ◽

Molecular Water ◽

Reduced Water ◽

Water Contents ◽

Absorption Measurements

Abstract Infrared absorption measurements of molecular water in sheared Cambrian quartzites in the footwall to the Moine thrust reveal a decrease in water content from 4080 to 1570 ppm with increasing recrystallization traced toward the overlying thrust at the Stack of Glencoul in northwest Scotland. These results are contrary to the expected correlation between shear strain and water content for quartz deformed by dislocation creep and water-weakening processes. The observed inverse correlation indicates that fluid inclusions and hydrous defects within grains were lost by mobile grain boundary sweeping and grain boundary diffusion. Although reduced water contents might lead to hardening as chemical weakening is diminished, quartz mylonites in the immediate footwall (5 mm) to the thrust are characterized by intense strain localization and contain the least water, and there is little evidence of shear zone widening. Water weakening appears to have been important throughout the quartz mylonites, controlled by the presence of water, not by water concentration. Fluids present within relict inclusions and at grain boundaries may have governed the high water fugacities critical for water weakening.

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Water Content in Garnet from Eclogites: Implications for Water Cycle in Subduction Channels

Minerals ◽

10.3390/min10050410 ◽

2020 ◽

Vol 10 (5) ◽

pp. 410

Author(s):

Yiren Gou ◽

Qin Wang ◽

Yan Li ◽

Richard Wirth

Keyword(s):

High Pressure ◽

Fluid Inclusions ◽

Water Cycle ◽

Broad Band ◽

Ultrahigh Pressure ◽

Molecular Water ◽

Retrograde Metamorphism ◽

Metamorphic Belt ◽

Absorption Bands ◽

The Mean

Garnet from eclogites often shows very heterogenous and extremely high hydroxyl concentration. Eight eclogite samples were selected from the Sulu ultrahigh-pressure terrane and the Sumdo high-pressure metamorphic belt (Lhasa). The mean hydroxyl concentration in pyrope-rich and almandine-rich garnet varies from 54 to 427 ppm H2O and increases with the retrogression degree of eclogites. TEM observations reveal nanometer-sized anthophyllite exsolutions and clinochlore inclusions in water-rich domains in garnet, where anthophyllite is partly replaced by clinochlore. Because of overlapping of the infrared stretching absorption bands for structural OH in garnet and chlorite, it is impossible to exclude contribution of chlorite inclusions to the estimated hydroxyl concentration in garnet. The broad band near 3400 cm−1 is attributed to molecular water and nanometer-sized chlorite inclusions. Anthophyllite exsolutions may be formed by decomposition of hydrous garnet from ultrahigh-pressure eclogites during exhumation. Significant amounts of water can be stored in garnet from massif eclogites in the forms of hydroxyl in garnet and nanometer-sized inclusions of anthophyllite and clinochlore, as well as fluid inclusions. Amphibolite facies retrograde metamorphism can significantly increase both hydroxyl concentration and water heterogeneity in garnet from massif eclogites. These nano-inclusions in garnet provide a window to trace the water cycle in subduction channels.

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MITIGATION YIELD SCALED METHANE EMISSION FROM RICE GROWN IN WATER STRESS CONDITIONS WITH BIOCHAR AND SILICATE AMENDMENTS

International Journal of Big Data Mining for Global Warming ◽

10.1142/s2630534821500078 ◽

2021 ◽

Author(s):

MUHAMMAD ASLAM ALI ◽

SANJIT CHANDRA BARMAN ◽

MD. ASHRAFUL ISLAM KHAN ◽

MD. BADIUZZAMAN KHAN ◽

HAFSA JAHAN HIYA

Keyword(s):

Water Stress ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Field Capacity ◽

Saturated Soil ◽

Rice Grain ◽

Standing Water ◽

Water Contents ◽

Soil Water Contents

Climate change and water scarcity may badly affect existing rice production system in Bangladesh. With a view to sustain rice productivity and mitigate yield scaled CH4 emission in the changing climatic conditions, a pot experiment was conducted under different soil water contents, biochar and silicate amendments with inorganic fertilization (NPKS). In this regard, 12 treatments combinations of biochar, silicate and NPKS fertilizer along with continuous standing water (CSW), soil saturation water content and field capacity (100% and 50%) moisture levels were arranged into rice planted potted soils. Gas samples were collected from rice planted pots through Closed Chamber technique and analyzed by Gas Chromatograph. This study revealed that seasonal CH4 emissions were suppressed through integrated biochar and silicate amendments with NPKS fertilizer (50–75% of the recommended doze), while increased rice yield significantly at different soil water contents. Biochar and silicate amendments with NPKS fertilizer (50% of the recommended doze) increased rice grain yield by 10.9%, 18.1%, 13.0% and 14.2%, while decreased seasonal CH4 emissions by 22.8%, 20.9%, 23.3% and 24.3% at continuous standing water level (CSW) (T9), at saturated soil water content (T10), at 100% field capacity soil water content (T11) and at 50% field capacity soil water content (T12), respectively. Soil porosity, soil redox status, SOC and free iron oxide contents were improved with biochar and silicate amendments. Furthermore, rice root oxidation activity (ROA) was found more dominant in water stress condition compared to flooded and saturated soil water contents, which ultimately reduced seasonal CH4 emissions as well as yield scaled CH4 emission. Conclusively, soil amendments with biochar and silicate fertilizer may be a rational practice to reduce the demand for inorganic fertilization and mitigate CH4 emissions during rice cultivation under water stress drought conditions.

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Telluride Mineralogy of the Deer Horn Au-Ag-Te-(Bi-Pb-W) Deposit, British Columbia: Implications for the Generation of Tellurides

The Canadian Mineralogist ◽

10.3749/canmin.1900103 ◽

2021 ◽

Author(s):

Jordan A. Roberts ◽

Lee A. Groat ◽

Paul G. Spry ◽

Jan Cempírek

Keyword(s):

British Columbia ◽

Fluid Inclusions ◽

Hanging Wall ◽

Oscillatory Zoning ◽

Stage Iii ◽

Fine Grained ◽

Melting Temperatures ◽

Homogenization Temperatures ◽

Intrusive Suite ◽

Cathodoluminescence Imaging

ABSTRACT The Deer Horn deposit, located 150 km south of Smithers in west-central British Columbia, is an Eocene polymetallic system enriched in Au-Ag-Te with lesser amounts of Bi-Pb-W; the Au and Ag are hosted in Te-bearing minerals and Ag-rich gold (Au-Ag alloy). A quartz-sulfide vein system containing the main zones of Au-Ag-Te mineralization and attendant sericite alteration occurs in the hanging wall of a local, spatially related thrust fault and is genetically related to the nearby Eocene Nanika granodiorite intrusive suite. Tellurium-bearing minerals commonly form isolated euhedral to subhedral grains or composite grains (up to 525 μm in size) of Ag-, Bi-, Pb-, and Au-rich tellurium-bearing minerals (e.g., hessite, tellurobismuthite, volynskite, altaite, and petzite). Panchromatic cathodoluminescence imaging revealed four generations of quartz. Within remnant cores of quartz I, local oscillatory zoning occurs in quartz II. Fine-grained veinlets of quartz III and IV crosscut quartz I and II, showing evidence of at least two deformation events; late-forming veinlets of calcite crosscut all generations of quartz. The tellurides and Ag-rich gold occur in stage III quartz. Three types of fluid inclusions were observed in stage III and IV quartz: (1) aqueous liquid and vapor inclusions (L-V); (2) aqueous carbonic inclusions (L-L-V); and (3) carbonic inclusions (vapor-rich). Primary fluid inclusions related to the telluride mineralization within quartz III were tested with microthermometry, along with a few primary inclusions from quartz IV. Homogenization temperatures are 130.0–240.5 °C for L-V inclusions and 268.0–336.4 °C for L-L-V inclusions. Aqueous carbonic inclusions had solid CO2 melting temperatures from –62.1 to –56.8 °C, indicating the presence of ≈1 to 30 mol.% dissolved methane in these inclusions. The Deer Horn Au-Ag-Te-(Bi-Pb-W) deposit is a reduced intrusion-related gold system characterized by sheeted veins, metal zoning, low salinity aqueous-carbonic fluids, and a genetic relationship to an Eocene granodiorite. Values of δ34S of pyrite vary from –1.6 to 1.6 per mil and are compatible with a magmatic source of sulfur.

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Effect of Nano-Carbon on Water Holding Capacity in a Sandy Soil of the Loess Plateau

Earth Sciences Research Journal ◽

10.15446/esrj.v21n4.66104 ◽

2017 ◽

Vol 21 (4) ◽

pp. 189-195 ◽

Cited By ~ 2

Author(s):

Beibei Zhou ◽

Xiaopeng Chen

Keyword(s):

Water Content ◽

Soil Water ◽

Loess Plateau ◽

Sandy Soil ◽

Water Retention ◽

Soil Mixture ◽

Cumulative Infiltration ◽

Nano Carbon ◽

Water Contents ◽

Soil Water Contents

The poor water retention capacity of sandy soils commonly aggregate soil erosion and ecological environment on the Chinese Loess Plateau. Due to its strong capacity for absorption and large specific surface area, the use of nanocarbon made of coconut shell as a soil amendment that could improve water retention was investigated. Soil column experiments were conducted in which a layer of nanocarbon mixed well with the soil was formed at a depth of 20 cm below the soil surface. Four different nanocarbon contents by weight (0%, 0.1%, 0.5%, and 1%) and five thicknesses of the nanocarbon- soil mixture layer ranging from 1 to 5 cm were considered. Cumulative infiltration and soil water content distributions were determined when water was added to soil columns. Soil Water Characteristic Curves (SWCC) were obtained using the centrifuge method. The principal results showed that the infiltration rate and cumulative infiltration increased with the increases of nanocarbon contents, to the thicknesses of the nano carbon-soil mixture layer. Soil water contents that below the soil-nano carbon layer decreased sharply. Both the Brooks-Corey and van Genuchten models could describe well the SWCC of the disturbed sandy soil with various nano carbon contents. Both the saturated water content (θs), residual water content (θr) and empirical parameter (α) increased with increasing nano carbon content, while the pore-size distribution parameter (n) decreased. The available soil water contents were efficiently increased with the increase in nanocarbon contents.

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Effects of differential drying rates on viability retention of recalcitrant seeds of Ekebergia capensis

Seed Science Research ◽

10.1017/s0960258500004438 ◽

1998 ◽

Vol 8 (4) ◽

pp. 463-471 ◽

Cited By ~ 64

Author(s):

N. W. Pammenter ◽

Valerie Greggains ◽

J. I. Kioko ◽

J. Wesley-Smith ◽

Patricia Berjak ◽

...

Keyword(s):

Water Content ◽

Exponential Function ◽

Time Course ◽

Drying Rate ◽

Recalcitrant Seeds ◽

Tissue Water ◽

Initial Water ◽

Viability Loss ◽

Drying Rates ◽

Water Contents

AbstractThe drying rate of whole seeds of Ekebergia capensis (Meliaceae) was shown to influence the response to desiccation, with rapidly dried seeds surviving to lower water contents. Short-term rapid drying (to water contents higher than those leading to viability loss) actually increased the rate of germination. The form of the time course of decline of axis water content varied with drying rate; slow drying could be described by an exponential function, whereas with rapid drying initial water loss was faster than predicted by an exponential function. These observations suggest that slow drying brought about homogeneous dehydration and that the rapid drying was uneven across the tissue. This raised the possibility that the different responses to dehydration were a function of different distributions of water in the axis tissue under the two drying regimes. However, ultrastructural observations indicated that different deleterious processes may be occurring under the different drying treatments. It was tentatively concluded that a major cause of viability loss in slowly dried material was likely to be a consequence of aqueous-based processes leading to considerable membrane degradation. Uneven distribution of tissue water could not be rejected as a contributory cause of the survival of rapidly dried seeds to low bulk water contents. The differential response to dehydration at different drying rates implies that it is not possible to determine a ‘critical water content’ for viability loss by recalcitrant seeds.

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An empirical model for describing the influence of water content and concentration of sulfamethoxazole (antibiotic) in soil on the total net CO2 efflux

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2020-0031 ◽

2020 ◽

Vol 68 (4) ◽

pp. 351-358

Author(s):

Miroslav Fér ◽

Radka Kodešová ◽

Barbora Kalkušová ◽

Aleš Klement ◽

Antonín Nikodem

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Solution Treatment ◽

Soil Microbial Activity ◽

Soil Samples ◽

Co2 Efflux ◽

The Impact ◽

Water Contents ◽

Soil Water Contents

AbstractThe aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.

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