Water contents of mantle xenoliths from Sytykanskaya kimberlite pipe (Yakutian diamondiferous province, Russia)

Author(s):  
Maria Kolesnichenko ◽  
Dmitriy Zedgenizov ◽  
Igor Ashchepkov

<p>Water plays a key role in evolution and dynamic of the Earth. It can change physical and chemical properties of mantle minerals, or the part of the mantle, for instance, the effect on mineral deformation and its impact on mantle rheology (Miller et al., 1987). Mantle xenoliths from kimberlites are one of direct source of information on the petrology and geochemistry of the deep mantle rocks.</p><p>Sytykanskaya pipe located in the central part of Yakutian diamondiferous province is characterized by a large amount of deep-seated xenoliths which contain relics of fresh minerals, e.g. clinopyroxenes, garnets, olivines, phlogopites, amphiboles, chromites, ilmenites and some other rare phases (Ashchepkov et al., 2015). Moreover it is known that there are several processes which can affect the mantle xenoliths, including metasomatism. Five peridotite xenoliths have been studied in order to indentify water enrichment. Using calibration coefficients (Bell et al., 2003) we calculated water content in the olivines. Water contents in olivine range from 12 to 92 ppm. In previous research (Kolesnichenko et al., 2017) we have studied peridotites from Udachnaya kimberlite pipe and found similar water content in olivines (2-95 ppm). So, the variably low water contents suggest a heterogeneous distribution of water beneath the mantle, which can be connected with metasomatism of essentially dry diamondiferous cratonic roots by hydrous and carbonatitic agents, and its related hydration and carbonation of peridotite accompanied by oxidation and dissolution of diamonds.</p><p><em>This work was supported by the Russian Science Foundation under Grant No 16-17-10067.</em></p><p>Miller, G. H., Rossman, G. R., & Harlow, G. E. (1987). The natural occurrence of hydroxide in olivine. Physics and chemistry of minerals, 14(5), 461-472.</p><p>Ashchepkov, I. V., Logvinova, A. M., Reimers, L. F., Ntaflos, T., Spetsius, Z. V., Vladykin, N. V., & Palesskiy, V. S. (2015). The Sytykanskaya kimberlite pipe: Evidence from deep-seated xenoliths and xenocrysts for the evolution of the mantle beneath Alakit, Yakutia, Russia. Geoscience Frontiers, 6(5), 687-714.</p><p>Bell, D. R., Rossman, G. R., Maldener, J., Endisch, D., & Rauch, F. (2003). Hydroxide in olivine: A quantitative determination of the absolute amount and calibration of the IR spectrum. Journal of Geophysical Research: Solid Earth, 108(B2).</p><p>Kolesnichenko, M. V., Zedgenizov, D. A., Litasov, K. D., Safonova, I. Y., & Ragozin, A. L. (2017). Heterogeneous distribution of water in the mantle beneath the central Siberian Craton: Implications from the Udachnaya Kimberlite Pipe. Gondwana Research, 47, 249-266.</p>

2020 ◽  
Author(s):  
Elena Shchukina ◽  
Mariya Kolesnichenko ◽  
Elena Malygina ◽  
Aleksey Agashev ◽  
Dmitry Zedgenizov

<p>The study of water content in the rock-forming minerals of mantle xenoliths, entrained in kimberlites, provides information about the water storage of the lithospheric mantle of ancient cratons. In mantle xenoliths, the water can be identified as several percentages by weight in hydrous minerals (e.g. phlogopite and amphibole) and up to 2000 ppm in nominally anhydrous minerals (NAMs; olivine, pyroxene, and garnet). Since the hydrous phases occur sporadically in mantle xenoliths, their NAMs reserve the main water content in the lithospheric mantle.</p><p>The water content in garnet and clinopyroxene from the mantle eclogites from the V. Grib kimberlite pipe (Arkhangelsk Diamondiferous Province, NW Russia) was analysed using Fourier transform infrared spectrometry. The studied samples are coarse-grained (grain sizes from 0.5–1.3 cm) bimineralic (garnet and clinopyroxene) eclogites with accessories of phlogopite, ilmenite, and rutile. The samples include high-MgO (three samples) and low-MgO (six samples) groups. The eclogites are interpreted as metamorphosed fragments of oceanic crustal rocks (basalt and gabbro for low-MgO eclogites and picritic/MgO basalt and troctolite for high-MgO eclogites) emplaced into the lithospheric mantle via a subduction event at 2.8 Ga. Based on pressure-temperature estimates (44–78 kbar; 940°C–1275°C), eclogites were transported by kimberlite from the range of depths of about 160 to >200 km.</p><p>The results show that all clinopyroxene grains contain structural water in the amount of 39 to 111 ppm, whereas only two garnet samples have detectable water in the amount of 211 and 337 ppm. The water incorporation into the clinopyroxene is mostly linked to M2 sites and aluminium in the tetrahedral position. The water content in the majority of eclogite clinopyroxene positively correlates with the jadeite component. The low-MgO eclogites with oceanic gabbro precursor contain significantly higher water concentrations in omphacites (70–111 ppm) and whole rock (35–224 ppm) compared to those with the oceanic basalt protolith (49–73 ppm and 20–36 ppm, respectively). The proposed observation is also confirmed by the negative correlations of water content in clinopyroxenes with a La/Yb ratio in clinopyroxene and WR water content versus the WR Yb concentration. The equilibrium pressure could be an additional factor that controls the water incorporation into the clinopyroxene of the high-MgO group.</p><p>Our results show that water content in the V. Grib pipe eclogites is not from the mantle metasomatism and therefore can reflect the water saturation of their protoliths. The eclogite portion of the lithospheric mantle beneath the V. Grib kimberlite pipe can have at least twice the water enrichment compared to peridotite sections, indicating that an Archean subduction event played an essential role in the water saturation of the mantle.</p><p>This work was supported by the Russian Science Foundation under grant no. 16-17-10067</p>


2020 ◽  
Vol 105 (6) ◽  
pp. 803-819
Author(s):  
Luc S. Doucet ◽  
Yongjiang Xu ◽  
Delphine Klaessens ◽  
Hejiu Hui ◽  
Dmitri A. Ionov ◽  
...  

Abstract Water and iron are believed to be key constituents controlling the strength and density of the lithosphere and, therefore, play a crucial role in the long-term stability of cratons. On the other hand, metasomatism can modify the water and iron abundances in the mantle and possibly triggers thermo-mechanical erosion of cratonic keels. Whether local or large scale processes control water distribution in cratonic mantle remains unclear, calling for further investigation. Spinel peridotite xenoliths in alkali basalts of the Cenozoic Tok volcanic field sampled the lithospheric mantle beneath the southeastern margin of the Siberian Craton. The absence of garnet-bearing peridotite among the xenoliths, together with voluminous eruptions of basaltic magma, suggests that the craton margin, in contrast to the central part, lost its deep keel. The Tok peridotites experienced extensive and complex metasomatic reworking by evolved, Ca-Fe-rich liquids that transformed refractory harzburgite to lherzolite and wehrlite. We used polarized Fourier transform infrared spectroscopy (FTIR) to obtain water content in olivine, orthopyroxene (Opx), and clinopyroxene (Cpx) of 14 Tok xenoliths. Olivine, with a water content of 0–3 ppm H2O, was severely degassed, probably during emplacement and cooling of the host lava flow. Orthopyroxene (49–106 ppm H2O) and clinopyroxene (97–300 ppm H2O) are in equilibrium. The cores of the pyroxene grains, unlike olivine, experienced no water loss due to dehydration or addition attributable to interaction with the host magma. The water contents of Opx and Cpx are similar to those from the Kaapvaal, Tanzania, and North China cratons, but the Tok Opx has less water than previously studied Opx from the central Siberian craton (Udachnaya, 28–301 ppm; average 138 ppm). Melting models suggest that the water contents of Tok peridotites are higher than in melting residues, and argue for a post-melting (metasomatic) origin. Moreover, the water contents in Opx and Cpx of Tok peridotites are decoupled from iron enrichments or other indicators of melt metasomatism (e.g., CaO and P2O5). Such decoupling is not seen in the Udachnaya and Kaapvaal peridotites but is similar to observations on Tanzanian peridotites. Our data suggest that iron enrichments in the southeastern Siberian craton mantle preceded water enrichment. Pervasive and large-scale, iron enrichment in the lithospheric mantle may strongly increase its density and initiate a thermo-magmatic erosion. By contrast, the distribution of water in xenoliths is relatively “recent” and was controlled by local metasomatic processes that operate shortly before the volcanic eruption. Hence, water abundances in minerals of Tok mantle xenoliths appear to represent a snapshot of water in the vicinity of the xenolith source regions.


2020 ◽  
Vol 6 (3) ◽  
pp. 1-33
Author(s):  
Konstantza Tonova

Abstract Room-temperature ionic liquids (ILs) represent molten salts entirely consisting of ions, usually a charge-stabilized organic cation and an inorganic or organic anion. ILs are liquids at ambient temperature but possess characteristics unusual for the common liquid solvents, such as negligible vapor pressure, high thermal stability and most over the ability to mix and match libraries of cations and anions in order to acquire desirable physical and chemical properties [1]. The opportunity to obtain tunable density, viscosity, polarity and miscibility with common molecular liquids gave rise to a variety of applications of the ILs [2] as environmentally benign solvents, extractants or auxiliaries. In particular, numbers of innovations in the methods for recovery and purification of biologically derived compounds involve ILs used solo or partnered with other liquids in biphasic systems [3,4,5]. It should be noted that the ILs are not intrinsically greener than the traditional solvents, given that their production is usually more resource-demanding, but the inherent potential for recycling and reuse, and for prevention of chemical accidents gives the ILs advantages ahead. The present chapter provides a state-of-the-art overview on the basic applications of the ILs in biphasic systems aimed at downstream processing of valuable fermentative products, enzymes and organic acids. Main industrially important enzymes, lipases and carbohydrases, are considered and a description of the IL-assisted aqueous biphasic systems (ABS) and the results obtained in view of enzyme yield and purity is made. ILs serve different functions in the ABS, main phase-segregating constituents (mostly in the IL/salt ABS) or adjuvants to the polymer/salt ABS. Enzyme isolation from the contaminant proteins present in the feedstock can be carried out either in the IL-rich or in the salt-rich phase of the ABS and for the reader’s convenience the two options are described separately. Discussion on the factors and parameters affecting the enzyme partitioning in the ABS with ILs guides the reader through the ways by which the interactions between the IL and the enzyme can be manipulated in favor of the enzyme purification through the choice of the ABS composition (IL, salt, pH) and the role of the water content and the IL-rich phase structure. The second part of the chapter is dedicated to the recovery of fermentative organic acids. Mostly hydrophobic ILs have been engaged in the studies and the biphasic systems thereof are summarized. The systems are evaluated by the extraction efficiency and partition coefficient obtained. Factors and parameters affecting the extraction of organic acids by ILs are highlighted in a way to unravel the extraction mechanism. The choice of IL and pH determines the reactive mechanism and the ion exchange, while the water content and the IL phase structure play roles in physical extraction. Procedures undertaken to enhance the efficiency and to intensify the process of extraction are also looked over. Finally, the experimental holes that need fill up in the future studies are marked. According to the author’s opinion an intense research with hydrophobic ILs is suggested as these ILs have been proved milder to the biological structures (both the microbial producer and the enzyme product), more effective in the organic acid recovery and suitable to perform “in situ” extraction. Extractive fermentation entails validation of ecological and toxicological characteristics of the ILs. The protocols for re-extraction of fermentative products separated by IL-assisted biphasic systems should be clearly settled along with the methods for ILs recycling and reuse. Novel more flexible approaches to process intensification can be implemented in order to adopt the separation by biphasic systems for use in industry.


Author(s):  
MUHAMMAD ASLAM ALI ◽  
SANJIT CHANDRA BARMAN ◽  
MD. ASHRAFUL ISLAM KHAN ◽  
MD. BADIUZZAMAN KHAN ◽  
HAFSA JAHAN HIYA

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.


2017 ◽  
Vol 21 (4) ◽  
pp. 189-195 ◽  
Author(s):  
Beibei Zhou ◽  
Xiaopeng Chen

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.


Solid Earth ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. 1025-1045 ◽  
Author(s):  
Andreas K. Kronenberg ◽  
Hasnor F. B. Hasnan ◽  
Caleb W. Holyoke III ◽  
Richard D. Law ◽  
Zhenxian Liu ◽  
...  

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.


1998 ◽  
Vol 8 (4) ◽  
pp. 463-471 ◽  
Author(s):  
N. W. Pammenter ◽  
Valerie Greggains ◽  
J. I. Kioko ◽  
J. Wesley-Smith ◽  
Patricia Berjak ◽  
...  

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.


Author(s):  
Patricia Argemira Costa ◽  
Izabel Cristina Freitas Moraes ◽  
Ana Mônica Q.B. Bittante ◽  
Paulo José do Amaral Sobral ◽  
Catarina A. Gomide ◽  
...  

The aim of this work was to study the rheological, thermal and some other physical-chemical properties of selected honeys produced in the Northeast of Brazil. Two samples were produced by native “Jandaira” bees (Melipona subnitida) and ten other samples by Africanized bees (Apis mellifera). The samples were analyzed for pH, water activity (aW), soluble solids and water content. Viscosity flow curves were obtained using a rheometer (25ºC, 0-100s-1). Thermal analyses were performed on a differential scanning calorimeter, with heating rate of 10ºC/min (-100 to 100ºC). The water content and the pH of the honey samples varied from 17.2 to 27.9% and from 3.2 to 4.2, respectively, and, the aW of the samples varied from 0.57 to 0.74. Two samples were out of specification with respect to water content, according to Brazilian laws. In relation to rheology, all honey samples showed Newtonian behaviour with no thixotropy or dilatancy. The viscosity varied as an exponential function of the water content. The highest viscosity was obtained for the sample with lower values of water content and aW. Thermograms showed a glass transition (Tg) occurring between -52.4 and -42.6ºC, in the samples produced by Apis mellifera and -67.6 and -57.0ºC for the other samples. A linear relationship was obtained between Tg and water content. In conclusion, the honey viscosity depended on the water content of the product. The higher the water value and therefore the greater the aw, the lower viscosity and Tg of the samples.


2020 ◽  
Vol 82 (6) ◽  
pp. 71-78
Author(s):  
Zita Letviany Sarungallo ◽  
Budi Santoso ◽  
Risma Uli Situngkir ◽  
Mathelda Kurniaty Roreng ◽  
Meike Meilan Lisangan

Refining of crude red fruit oil (CRFO) through the degumming and neutralization steps intended to produce oil free of impurities (non triglycerides) such as phospholipids, proteins, residues and carbohydrates, and also reducing the amount of free fatty acids (FFA). This study aims to determine the effect of red fruit oil purification through degumming and neutralization stages on chemical properties, fatty acid composition, carotenoid content and tocopherol of red fruit oil (RFO). The results showed that degumming of CRFO did not affect the decrease in water content, FFA levels, peroxide numbers, iodine values, carotenoids and tocopherols content; but decrease in levels of phosphorus, β-carotene and α-tocopherol. Neutralization of degummed-RFO (DRFO) did not affect the decrease in water content, iodine value, carotenoid, tocopherol and α-tocopherol; but the FFA levels, peroxide number, phosphorus and β-carotene levels decreased significantly. The fatty acid composition of RFO was dominated by unsaturated fatty acids (± 75%), which increases through degumming and neutralization stages. β-carotene is more sensitive than α-tocopherol during refining process of crude oil, but in general, this process can improve the RFO quality.


2020 ◽  
Vol 68 (4) ◽  
pp. 351-358
Author(s):  
Miroslav Fér ◽  
Radka Kodešová ◽  
Barbora Kalkušová ◽  
Aleš Klement ◽  
Antonín Nikodem

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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