The initial concentration distributions were obtained in unannealed crystals. The ZrO 2 layer is not detected because its O and Si isotopes have probably been …
Reconciling the diverse records of magmatic events preserved by multiple crystals and minerals in the same sample is often challenging. In the case of basaltic–andesites from Volcán Llaima …
1. Introduction. Olivine is a family of minerals with an orthorhombic structure and a general composition of (Mg, Fe) 2 SiO 4.The Mg 2 SiO 4 magnesium-rich end-member is called forsterite, and the Fe 2 SiO 4 iron-rich end-member is called fayalite. With an iron composition close to 10 %, olivine is the main constituent of the Earth's mantle …
The D bulk Ca is calculated using the Ca concentration of experiment melts (with SiO 2 < 57 wt%) and residual solid phases during partial melting (Table S1). Olivine phenocrysts, which are the first minerals to crystallize from mantle-derived magma, have the potential to record the compositions of primary melt.
The position of the crystal–film interface was initially set to be the same as that of the unannealed sample that was coated and analyzed in. Si and O diffusion: the effect of water and pressure ... We then defined linear relations between the water concentration in Fo90 olivine, the elastic moduli and their pressure derivatives, which …
To address this question we determined H 2 O, CO 2, F, Cl and S concentrations in olivine-hosted melt inclusions of high-Mg volcanic rocks of the Siberian Traps Large Igneous Province that bracket the main pulse of volcanism at about 252–250 Ma, and can be classified as melanephelinites and meimechites. Both rock types belong …
Average olivine Cr concentrations per sample range from 18 to 39 ppm (Table 1), and olivine grains from silicate cumulates commonly have lower Cr contents than those from chromitites (Fig. 3). Average orthopyroxene Cr concentrations per sample are higher than those of olivine, ranging from 2778 to 4239 ppm ( Table 1 ), and are not ...
[1] We report analyses of hydrogen abundance in experimentally annealed and natural mantle minerals using FTIR and use these data to establish calibration lines for measurement of H 2 O …
Geological observations of Mars indicate a dense early atmosphere ranging from 0.25 to 4 bar of CO 2 (1, 2).However, Mars' current surface reservoir only amounts …
Thin amorphous films (1-2 nm) at olivine grain boundaries in mantle xenoliths from San Carlos, Arizona ... high energy grain boundaries. In the following, Al2O3, TiO2 and CaO are considered as impurities because their concentration in olivine usually is very low (.0.1 wt%). The concentration of CaO might be slightly higher. The mean value and ...
Until now, the concentrations of CO 2 in the mantle have mostly been estimated based on the dissolved CO 2 in erupted basaltic glasses (Michael and Graham, 2015; Shimizu et al., 2016), melt inclusions (Miller et al., 2019; Saal et al., 2002) and associated mantle-derived fluids (such as trapped gas bubbles in basalts and …
Introduction. The study of olivine-hosted melt inclusions trapped at depth by growing olivine crystals, before a rising magma has the opportunity to degas completely, presents an exceptional opportunity to directly measure pre-eruptive volatile concentrations of basaltic rocks, thereby allowing characterization of the source and …
Another process could explain the observed parallel FeO and MgO concentrations: the dissolution of olivine in the silicate melt. Olivine dissolution experiments have been done by Zhang et al. [14] in silicate melts at high pressure (Fig. 5). Their results show composition profiles with the same shape than our composition …
Carbon sequestration Mineral carbonation. surface injection and storage of CO2, olivine alteration was studied at 60 °C and 100 bar CO2 pressure, including olivine dissolution …
The trace element composition of olivine is a rapidly growing research area that has several applications of great potential. Mantle olivines can be distinguished from volcanic olivines by lower concentrations of Ca (<700 ppm), Ti (<70 ppm), and often Cr.The melting of pyroxenites derived from recycled ocean crust can be recognized in …
In this study, the role of Fe(II) in the thin H2O film carbonation of olivine was investigated using in situ high pressure infrared spectroscopy and ab initio thermodynamic calculations. Experiments were performed at 50 °C and 90 bar in both scCO2 and scCO2 with 1% H2 at a relative humidity of 79% on synthetic forsterite, fayalite, and two Mg ...
A second major reason to review olivine dissolution rates is that its reactivity is relatively simple. Its structure is comprised of isolated Si O 4 4− tetrahedra linked by …
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A summary of the kinetic parameters together with the experimental conditions found in the literature can be seen in Table 1.The values of E a range from 25 to 105 kJ/mol, n from 0.33 to 1.1, and r from 2 · 10 −13 to 5 · 10 −12 mol cm −2 s −1.However, the most frequently mentioned value for the reaction order is around 0.5, and the …
We have determined Fe–Mg diffusion coefficients in olivines from different sources (Nanga Parbat, Pakistan and San Carlos, Arizona, USA) at atmospheric pressure as a function of composition, oxygen fugacity (10−5–10−12 Pa) and temperature (700–1200°C) using thin films produced by pulsed laser deposition and RBS to analyze …
The deep carbon (C) cycle governs the Earth's surface CO 2 concentration and temperature, and thus its habitability (Dasgupta and Hirschmann 2010; Dasgupta et al. 2013; Plank and Manning 2019).The C inventory of oceanic plates determines the mass of C subducted into the mantle (Dasgupta 2013; Kelemen and Manning 2015; Liu et al. …
The H + concentration in the void between the well-crystallized carbonates formed by carbonation and the non-reacted olivine was believed to be the same as that in the aqueous bulk solution. The decrease in particle size, increase in temperature, HCO 3 − concentration and ionic strength in solution can dramatically enhance the carbonation ...
The initial concentration distributions were obtained in unannealed crystals. The ZrO 2 layer is not detected because its O and Si isotopes have probably been homogenized by exchange with the olivine thin film. Note that the O diffusion profile (a) shows that the olivine thin film has also exchanged isotopes with the surrounding fluid.
Trace concentrations of H 2 O in olivine strongly affect diverse mantle and magmatic processes. H 2 O in olivine has been difficult to accurately quantify due to challenges in sample preparation and measurement, as well as significant uncertainties in standard calibrations. Here we directly compare secondary-ion mass spectrometry …
Download scientific diagram | Fe concentration depth profiles from olivine thin film/orthopyroxene diffusion couples obtained from the RBS spectra using the software RBX (Kotai 1994). Shown are ...
Introduction. Olivine, a silicate with composition (Mg,Fe) 2 SiO 4, is the major constituent (60 to 80 %) of the Earth's mantle up to ca. 410 km deep where it transforms into a high-pressure polymorph, called wadsleyite. The mechanical properties of olivine are of primary importance in geodynamics since this mineral controls the …
ρ m and ρ c are the densities of melt and olivine, respectively. ρ c /ρ m is taken as a constant of 1.2 in this study. C i (t) and C e (t) are the interior and exterior water concentrations.Equation is the mass balance equation across the internal melt–olivine boundary.The left-hand side of Eq. is the change in the water mass in the melt inclusion, …
Most olivine concentration profiles were acquired using a 20 keV accelerating voltage, a 250 nA current, a spot size of 1–5 microns and an element setup consisting of Si, Mg, Al, Fe, Cr, Mn, Ni, Ca, P. ... thin film-olivine or powder-olivine couples. Interface reactions (growth, dissolution) or the lack of a perfect interface …
Enhanced weathering of (ultra)basic silicate rocks such as olivine-rich dunite has been proposed as a large-scale climate engineering approach. When implemented in coastal environments, olivine …
Due to the similar physical and chemical properties of ilmenite and olivine, separating them is challenging. The flotation process, with the use of collectors, is an effective method. In this study, a ternary collector consisting of aluminum ion (III), benzohydroxamic acid (BHA), and sodium oleate (NaOL) was prepared for the flotation …
We have determined Fe-Mg diffusion coefficients in olivines from different sources (Nanga Parbat, Pakistan and San Carlos, Arizona, USA) at atmospheric pressure as a function of composition, oxygen fugacity (10-5-10-12 Pa) and temperature (700-1200°C) using thin films produced by pulsed laser deposition and …
However, real concentrations of H 2 O and other volatiles in meimechites may be higher than reported previously. In this paper we address this question by analyzing H 2 O, CO 2, F, Cl and S concentrations in olivine-hosted melt inclusions from high-Mg melts of the Siberian Traps Large Igneous Province. We also discuss applicability of Cr …
Detailed observations of the geometry and chemistry of the thin films, before and after pre- as well as diffusion anneals reveal that depending on temperature, composition and other factors the films may behave differently. It is necessary to identify and distinguish between these …
Again, olivine thin films were used as the diffusant source, but even the relatively smooth olivine films show considerable roughness (Figs. 6b,d), which generally increases with increasing ...
1. Introduction. Olivine is a family of minerals with an orthorhombic structure and a general composition of (Mg, Fe) 2 SiO 4.The Mg 2 SiO 4 magnesium-rich end …
