Minor Minerals Research Articles

Understanding the Competitive Scenario of Granite Exports from India to USA

India is blessed with ample varieties and reserves of natural resources, most of them having a robust market not only domestically, but also internationally. We produce as many as 87 minerals, which include 4 fuels, 10 metallic, 47 non-metallic, 3 atomic, and 23 minor minerals (Ministry of Mines, 2013). Granite falls under the minor minerals category. The present paper aimed to explore the potential of the Indian granite sector and the major market for it internationally. In the world market, there are around 300 varieties of granite that are available, out of which India supplies nearly 200 varieties. Some of these varieties like jet black and galaxy black are supplied uniquely by India in the international market. There is continuously growing demand for Indian black granite in the international markets for various needs. As building construction grows indiscriminately to meet the needs of a growing world population, it creates demand for building stones like limestone, marble, slate, and granite. Due to its (granite) beautiful finish and sturdiness suitable for interior and exterior decor, there has been a rise in its demand. In fact, in several premium constructions, it is replacing the Italian marble as well. As USA is the largest market for Indian granite, the paper tried and explored the analysis and strategies of other competing nations present in the U.S. market, which can be of great help for Indian granite exporters. An attempt was made to explore the strategic approach in order to make certain vital observations to lay down conclusions. The paper contemplated that the government, the private sector, and locals need to work together to achieve sustainable growth in the Indian granite sector within India and internationally.

Impact of copper mines and smelter on groundwater quality (Case Study: Rajasthan State in India)

Rajasthan is one of the main mineral potential state of India. During the last 30 years it has witnessed enormous expansion of mining industries, but mining of most of the minor minerals coupled with changing climate has posed serious problems to the environmental fabric in the state, apart from base metal beneficiation plants. Groundwater is also being polluted day-by-day by effluents generated from mineral wastes and beneficiation processes in the vicinity of mining sites such as Khetri. Pollutant concentrations were measured in groundwater at the vicinity of Khetri copper mining project, Rajasthan to investigate the influence of copper mining on environment. Pollutant concentrations in groundwater were investigated. Copper metal concentration in water samples were found above the maximum desirable limit in two sources: G4 and G5, due to washing away of mineral with water. Mining industry has deteriorated quality of groundwater resources in the state of Rajasthan, and these industries are becoming centers of pollution sources which need timely actions at government level so that natural resources such as groundwater can be protected.

A rock fragment related to the magnesian suite in lunar meteorite Allan Hills (ALHA) 81005

Among the lunar samples that were returned by the Apollo missions are many cumulate plutonic rocks with high Mg# [molar Mg/(Mg+Fe) in %] and abundances of KREEP elements (potassium, rare earth elements, phosphorus, U, Th, etc.) that imply KREEP-rich parental magmas. These rocks, collectively called the magnesian suite, are nearly absent from sampling sites distant from Imbrium basin ejecta, including those of lunar highlands meteorites. This absence has significant implications for the early differentiation of the Moon and its distribution of heat-producing elements (K, Th, U). Here, we analyze a unique fragment of basalt with the mineralogy and mineral chemistry of a magnesian suite rock, in the lunar highlands meteorite Allan Hills (ALH) A81005. In thin section, the fragment is 700 × 300 μm, and has a sub-ophitic texture with olivine phenocrysts, euhedral plagioclase grains (An97-70),and interstitial pyroxenes. Its minerals are chemically equilibrated. Olivine has Fe/Mn ~ 70 (consistent with a lunar origin), and Mg# ~80, which is consistent with rocks of the magnesian suite and far higher than in mare basalts. It has a rich suite of minor minerals: fluorapatite, ilmenite, Zr-armalcolite, chromite, troilite, silica, and Fe metal (Ni = 3.8%, Co = 0.17%). The metal is comparable to that in chondrite meteorites, which suggests that the fragment is from an impact melt. The fragment itself is not a piece of magnesian suite rock (which are plutonic), but its mineralogy and mineral chemistry suggest that its protolith (which was melted by impact) was related to the magnesian suite. However, the fragment’s mineral chemistry and minor minerals are not identical to those of known magnesian suite rocks, suggesting that the suite may be more varied than apparent in the Apollo samples. Although ALHA81005 is from the lunar highlands (and likely from the farside), Clast U need not have formed in the highlands. It could have formed in an impact melt pool on the nearside and been transported by meteoroid impact. Lunar highlands meteorites should be searched for rock fragments related to the magnesian-suite rocks, but the fragments are rare and may have mineral compositions similar to some meteoritic (impactor) materials.

Determining Mineralogy on Mars with the CheMin X-Ray Diffractometer

The rover Curiosity is conducting X-ray diffraction experiments on the surface of Mars using the CheMin instrument. The analyses enable identification of the major and minor minerals, providing insight into the conditions under which the samples were formed or altered and, in turn, into past habitable environments on Mars. The CheMin instrument was developed over a twenty-year period, mainly through the efforts of scientists and engineers from NASA and DOE. Results from the first four experiments, at the Rocknest, John Klein, Cumberland, and Windjana sites, have been received and interpreted. The observed mineral assemblages are consistent with an environment hospitable to Earth-like life, if it existed on Mars.

Small quantity but large effect — How minor phases control strain localization in upper mantle shear zones

Low viscosity domains such as localized shear zones exert an important control on the geodynamics of the uppermost mantle. Grain size reduction and subsequent strain localization related to a switch from dislocation to diffusion creep, is one mechanism to form low viscosity domains. To sustain strain localization, the grain size of mantle minerals needs to be kept small over geological timescales. One way to keep olivine grain sizes small is by pinning of mobile grain boundaries during grain growth by other minerals (second phases). Detailed microstructural studies based on natural samples from three shear zones formed at different geodynamic settings allowed the derivation of the olivine grain-size dependence on the second-phase content. The polymineralic olivine grain-size evolution with increasing strain is similar in the three shear zones. If the second phases are to pin the mobile olivine grain boundary the phases need to be well mixed before grain growth. We suggest that melt–rock and metamorphic reactions are crucial for the initial phase mixing in mantle rocks. With ongoing deformation and increasing strain, grain boundary sliding combined with mass transfer processes and nucleation of grains promotes phase mixing resulting in fine-grained polymineralic mixtures that deform by diffusion creep. Strain localization due to the presence of volumetrically minor minerals in polymineralic mantle rocks is only important at high strain deformation (ultramylonites) at low temperatures (<~800°C). At smaller strain and stress conditions and/or higher temperatures other parameters like overall energy available to deform a given rock volume, the inheritance of mechanical anisotropies or the presence of water or melts needs to be considered to explain strain localization in the upper mantle.

Major, Minor and Toxic Minerals and Anti-Nutrients Composition in Edible Mushrooms Collected from Ethiopia

Major (Na, K, Ca, Mg, P), minor (Mn, Cu, Fe, Zn) and toxic (Pb, Cd) minerals composition of twelve edible mushrooms (Pleurotus ostreatus, Lentinula edodes, Agaricus bisporus #1 (fresh), Agaricus bisporus #2 (canned), Agaricus campestris, Laetiporus sulphureus, Termitomyces clypeatus, Termitomyces microcarpus #1, Termitomyces microcarpus #2, Termitomyces aurantiacus, Termitomyces letestui and Termitomyces species) collected from three regions of Ethiopia were analyzed. The samples were further investigated for their antinutrients (phytate and condensed tannin) to determine bioavailability of minerals. All the results are expressed in dry basis (db). The major minerals concentration (mg/g) ranged: Na (0.41-34.8), K (3.66-42.4), Ca (0.29-6.45), Mg (0.57-2.12) and P (0.71-2.82). The minor (mg/kg) ranged: Fe (32.5-6835.9), Zn (26.6-87.6), Cu (5.69-45.9) and Mn (0.96-138.6). The toxic metal lead was detected (1.52-18.0 mg/kg), indicating most of the mushrooms samples exceeded the weekly tolerance limit set for Pb with more proportion in wild than cultivated mushrooms. Cadmium was detected only in A.campestris (4.08 mg/kg). The anti-nutrients (mg/100 g) were significantly varied with phytate ranged from 31.3 to 242.8 and condensed tannin from 4.81 to 31.7. The calculated molar ratio between phytate and Fe, Zn and Ca was above the suggested critical values indicating the bioavailability of Fe, Zn and Ca to be high. In conclusion, the results imply that the edible mushrooms have high concentrations of essential minerals with lower anti-nutrients that make them bioavailable to the human body. Although, the consumption of some contaminated mushrooms should be avoided.

Nutrient Analysis of Soil Collected from Panuchakuli Village, Kanyakumari District, Kanyakumari

Soil reflects both natural and human activities. It changes in its properties with respect to environmental issues. Inorder to know the soil properties in the particular location, it was decided to study the nutrient contents, microbial analysis of the soil. The pH, organic carbon, NPK, minor nutrients was assessed. The pH was found to be alkaline. The NPK level was moderate in amount, and all the minor minerals were higher in amount except boron which was absent. The total mineral content of the soil was 266.19kg/acre. Among the microbes tested, the bacteria was found in higher concentration, followed by fungi and very less of actinomycetes was present. From the results it is concluded, that the soil contains sufficient organic carbon, nutrients, microbes essential for growth of the plant.

Spectroscopic Characterization and Quantitative Estimation of Natural Weathering of Silicates in Sediments of Dikrong River, India

The sediments samples were collected from the Dikrong River at various sites to assess the weathering nature and mineral characterization. The Fourier Transform Infrared (FTIR) and X-ray fluorescence (XRF) spectroscopic techniques have been used to characterization of minerals in the sediment samples. The plagioclase index of alteration (PIA), chemical index of alteration (CIA) and index of compositional variation (ICV) are investigated for evaluating the weathering nature in the sediment. The obtained results show the presence of quartz, feldspar in different structure and kaolinite as major minerals. Carbonates and organic carbon are found as minor minerals. The correlations of SiO2 with major elements are authenticated the presence of bulk quartz grains and primary depositional environment. The presence of metamorphosed pyrophanite (MnTiO3) in the adjoined areas is reported. The presence of infrared absorption peaks in between 1611 - 1622 cm?1 in this study is indicative to the weathered metamorphic origin of the silicate minerals. The index of compositional variation indicates the presence of less clay minerals and more rock forming minerals such as plagioclase and alkali-feldspar. The obtained results exhibit the area belongs to the intermediate silicate weathering.

Rare earth element geochemistry of the Upper Permian limestone: the Kanigorgeh mining district, NW Iran

The limestone of the Ruteh Formation of Upper Permian age in the Kanigorgeh district (northeast of Bukan, NW Iran) contains several layers and lenses of bauxitic ores. Mineralogical data show that this limestone consists of calcite and quartz as major and plagioclase, kaolinite, and hematite as minor mineral phases. Geochemical analyses reveal that the proportions of ?REEs (La-Lu) in this limestone vary from 35.28 to 160.78 ppm. The values of Eu and Ce anomalies (normalized to PAAS) of the limestone have ranges of 1.11-1.68 and 0.89-1.16, respectively. The high values of ?REEs; low values of Y/Ho; strong and positive correlations between ?REEs and elements such as Si, Al, Ti, V, Co, Ni, Rb, Cu, and Nb; and negative correlations between CaO and ?REEs suggest that the observed variations in values of ?REEs in the limestone were controlled principally by the quantity of detrital materials. Geochemical data also illustrate that the observed positive Eu anomalies in the limestone may be due to the presence of plagioclase and also a function of diagenetic processes. Furthermore, the variations in Ce anomalies may be due to the detrital input. The distribution of REEs (normalized to chondrite) illustrates different patterns in both rocks (the limestone and the bauxitic ores) in light of differentiation degree of LREEs from HREEs and values of conservative indexes such as Eu anomaly. Considering these pronounced discrepancies, it appears that the limestone, despite having relatively high concentration of ?REEs, did not play a significant role in supplying lanthanides for the bauxitic ores.

Proximate and Minor Mineral Content in Some Selected Basil Leaves of Ocimum gratissimum L, in Libya

and exist in whorled and panicled inflorescence. The fruits of nutlets are subglose, 1.5-2mm diameter and slightly rugose. Ocimum gratissinum is popularly used in folk medicine for the treatment of upper respiratory tract infection, diarrhea, cough, fever, gonorrhea, worm infection, stomach aches, headaches, pile, pneumonia and surface wound. It is also implicated in blood coagulation, anti- inflammatory, cardiovascular and renal function properties have been observed (7). Ocimum gratissinum is a herbaceous plant which belongs to the Labiatae family. The plant is indigenous to tropical areas especially Libya and it is also in West Africa. The leaves of Ocimum gratissinum are used to prepare soups and porridge for women after delivery among the Igbos of Africa and also in the management of the baby's cord after delivery. The plant is used as food spice and for the treatment of ailments such as; malaria, diabetes, respiratory and urinary tract infections, cough, fever, diarrhea, abdominal pains, pneumonia, conjunctivitis, oral wounds and tooth infection (8), (9). In this study, therefore, the leaves from three region of Ocimum gratissinum collected from Libya was analyzed for proximate and minerals constituents with view if there are variations in these accessions and if there are, to determine the heritable and non heritable components and estimates of heritability and genetic advance expected.

Tephra records from abyssal sediments off western Sumatra in recent 135 ka: evidence from Core IR-GC1

Three volcanic ash layers were identified in a deep-sea Core IR-GC1 from the north-eastern Indian Ocean, adjacent to western Indonesian arc. They were dominated by glass shards with minor mineral crystals, such as plagioclase, biotite, and hornblende. According to the morphology and major element compositions of the representative glass shards, combined with the 18O-based age, it is suggested that ash Layer A is correlated to the youngest Toba tuff (YTT), Layer B is supposed to be associated with a new eruption of Toba caldera in an age of 98 to 100 ka. Ash Layer C is different the geochemistry characteristics than those of Layer A and Layer B, suggesting that Layer C was not originated from Toba but registered another volcanic eruption event.

The influence of natural trace element distribution on the mobility of radionuclides. The exemple of nickel in a clay-rock

The natural distribution of nickel (Ni) in the Callovian–Oxfordian clay-rich rock of Bure (France) was investigated, together with that of cobalt (Co), zinc (Zn) and lead (Pb). The most Ni-enriched phases are pyrite (∼400×10−6gg−1 Ni), sphalerite (∼300×10−6gg−1), chlorite (∼285×10−6gg−1), organic matter (∼300×10−6gg−1), muscovite (100–200×10−6gg−1) and possibly carbonate minerals (mainly calcite and minor dolomite, ∼10×10−6gg−1). Despite their high abundance (up to ∼80% in the upper part of the formation), carbonate minerals are quantitatively a minor Ni reservoir; most of the Ni is borne by chlorite and pyrite, which are minor mineral phases. Co and Ni have a similar distribution, whereas Pb and Zn have partly different reservoirs (e.g. sphalerite – ZnS).In parallel, the equilibrium between rock and pore water was investigated, and importance of pyrite (or reduced sulfur minerals) as Ni reservoir in the formation was confirmed from an in situ experiment perturbed by oxidation processes. Under unperturbed conditions (laboratory kinetics experiments and in situ pore water sampling), Ni solubility ranges from ∼0.2 to 1×10−6molL−1. The rock sorption capacities with regards to radioactive Ni (in the range of ∼1.5×10−10molL−1 to ∼1.5×10−9molL−1 of spiked 63Ni) were also tested using batch experiments. Sorption kinetics of 63Ni on the Callovian–Oxfordian clay-rich rock was explained by two mechanisms: fast and reversible sorption onto clay minerals and slow incorporation in another phase. Indirect evidences point out the likely major role of calcite in this latter process albeit pyrite and organic matter may also be involved. Reversible sorption of Ni onto clay minerals surfaces is shown to be hindered by competition processes with other naturally occurring bivalent metals (e.g. naturally-occurring Ni and Zn), thus decreasing the 63Ni Rd value as compared to the value predicted from a bottom-up approach considering only 63Ni sorption on clay minerals. At longer time scale, irreversible 63Ni trapping is observed and compensates the competition processes. These two mechanisms were implemented in a reactive transport model to illustrate their influence on the prediction of long-term behavior of radioactive Ni. Migration distances are increased by the effect of cation competition, and reduced in a comparable extent by irreversible trapping in the time frame investigated.

A novel EBSD‐based finite‐element wave propagation model for investigating seismic anisotropy: Application to Finero Peridotite, Ivrea‐Verbano Zone, Northern Italy

AbstractA novel electron backscatter diffraction (EBSD) ‐based finite‐element (FE) wave propagation simulation is presented and applied to investigate seismic anisotropy of peridotite samples. The FE model simulates the dynamic propagation of seismic waves along any chosen direction through representative 2D EBSD sections. The numerical model allows separation of the effects of crystallographic preferred orientation (CPO) and shape preferred orientation (SPO). The obtained seismic velocities with respect to specimen orientation are compared with Voigt‐Reuss‐Hill estimates and with laboratory measurements. The results of these three independent methods testify that CPO is the dominant factor controlling seismic anisotropy. Fracture fillings and minor minerals like hornblende only influence the seismic anisotropy if their volume proportion is sufficiently large (up to 23%). The SPO influence is minor compared to the other factors. The presented FE model is discussed with regard to its potential in simulating seismic wave propagation using EBSD data representing natural rock petrofabrics.

Reflectance spectroscopy of plagioclase-dominated mineral mixtures: Implications for characterizing lunar anorthosites remotely

Anorthositic rocks dominate the Moon’s upper crust. As remnants of the lunar magma ocean (LMO), small variations in the mineralogy of these rocks may hold key information about the homogeneity of LMO composition and solidification processes. Orbital near-infrared (NIR) sensors are sensitive to mineralogy, but technologic advances have only recently enabled detection of the plagioclase component in crustal rocks based on an absorption band centered near 1250 nm. Anorthosites occupy a unique mineralogic range that is well suited for NIR studies: the highly transparent component, plagioclase, is present in high abundances while the spectrally dominant mafic or oxide minerals are present in only minor abundance. As a result, spectra of anorthosites are more likely than many other rock types to contain visually discernable signatures from more than one mineral component, facilitating their identification and characterization in NIR data. In support of new NIR measurements for the Moon, we present laboratory spectral analyses of well-controlled plagioclase-dominated mineral mixtures. We focus on the spectral effects of varying mafic and oxide composition and abundance in mixtures with a common plagioclase end-member. The results demonstrate that plagioclase can be a significant contributor to reflectance spectra when strongly absorbing minerals are present in low abundance. We show that the contribution of plagioclase is more pronounced in mixtures with pyroxenes and certain spinels, but more easily masked in mixtures containing small amounts of olivine. Differences in minor mineral composition are clearly expressed in bulk spectra. Modeling of mixtures using a Hapke nonlinear approach accurately estimates mineral abundances in laboratory spectra to within 5 vol% for mixtures with ≥90 vol% plagioclase. Together, these results imply that not only should orbital NIR data sets be able to discern the presence of plagioclase in anorthositic crustal exposures, but also that detailed information about anorthosite mineral assemblages can be reliably accessed in reflectance spectra.

Mineralogy, geochemistry and petrogenesis of the V-Ti-bearing and chromiferous magnetite deposits hosted by Neoarchaean Channagiri Mafic-Ultramafic Complex, Western Dharwar Craton, India: Implications for emplacement in differentiated pulses

Abstract The Channagiri Mafic-Ultramafic Complex occupies lowermost section of the Neoarchaean Shimoga supracrustal group in the Western Dharwar Craton. It is a segmented body occupying the interdomal troughs of granitoids. The magnetite deposits occur in the northeastern portion; typically occupying the interface zone between gabbro and anorthositic. Mineralogically, the deposits are simple with abundant magnetite and ilmenite. Hogbomite is a consistent minor mineral. Magnetites are typically vanadiferous (0.7–1.25% V2O5). Ilmenite consistently analyses more MgO and MnO than coexisting magnetite. Chlorite, almost the only silicate present; lies in the range of ripidolite, corundophilite and sheridanite. The chromiferous suit occupying eastern side of Hanumalapur block (HPB) contains Fe-Cr-oxide analysing 37.8–11.9% Cr2O3 and 40.5–80% FeOt. In these too, chlorite, typically chromiferous (0.6–1.2% Cr2O3), is the most dominant silicate mineral. Geochemistry of V-Ti-magnetite is dominated by Fe, Ti and V with Al, Si, Mg and Mn contributing most of the remaining. Cr, Ni, Zn, Co, Cu, Ga and Sc dominate trace element geochemistry. The Cr-magnetite is high in Cr2O3 and PGE. Two separate cycles of mafic magmatism are distinguished in the CMUC. The first phase of first cycle, viz., melagabbro-gabbro, emplaced in the southeastern portion, is devoid of magnetite deposits. The second phase, an evolved ferrogabbroic magma emplaced in differentiated pulses, occupying northeastern portion of the complex, consists of melagabbro→gabbro-anorthosite→V-Ti magnetite→ferrogabbro sequence. Increase in oxygen fugacity facilitated deposition of V-Ti magnetite from ferrogabbroic magma pulse emplaced in late stages. The second cycle of chromiferous PGE mineralized suite comprises fine-grained ultramafite→alternation of pyroxinite-picrite→Crmagnetite sequence formed from fractionation of ferropicritic magma. HPB also includes &gt;65m thick sill-like dioritic phase at the base of the ferriferous suit and a sinuous band of coarse-grained ultramafite enclosed within the chromiferous suit; both unrelated to the two mafic magmatic cycles.

Development of a process flowsheet for the beneficiation of low-grade iron ore fines from the Bellary-Hospet region of Karnataka, India

It was possible to beneficiate a low-grade iron ore fines sample from Bellary-Hospet, Karnataka, India assaying 56% Fe, 9.1% SiO2 and 5.2% Al2O3 and produce two concentrates, namely, a sinter-grade fines concentrate (43.7% by weight), assaying 63.6% Fe, 2.6% SiO2 and 1.7% Al2O3, and a pellet-grade concentrate (30.7% by weight) assaying 64.7% Fe, 2.9% SiO2 and 1.7%Al2O3. Rejects (25.6% by weight) assayed 32.5% Fe, 27.9% SiO2 and 15.4% Al2O3. The mineralogical characterization indicated that the sample consisted of 69.5% iron-bearing minerals (56% hematite, 7.5% martite and 6% goethite-limonite), 12.5% quartz and 15.2% clay, and the rest were minor minerals. Liberation size was found to be in the size range of 25 to 100 μm. The process flow sheet consists of jigs, spirals, grinding and low- and high-intensity magnetic separation of the deslimed feed.

A Synthesis of Instrumental Analytical Techniques for Examination of the Thermal History of Pallasite Meteorites

Pallasites are a unique group of meteorites consisting of a mixture of approximately equal proportions of olivine grains in a matrix of Fe-Ni metal. These meteorites provide physical samples of the interior of a differentiated planetary body. As such, they provide direct geochemical clues to planetary differentiation processes. In this study, one large collaborative effort is undertaken to analyze a suite of 14 main-group pallasite specimens by several different instrumental analytical techniques in an attempt to provide a comprehensive picture of formation processes, temperatures and timescales. The suite of specimens chosen come from both the main group pallasites and the Eagle Station trio, and encompass a range of fayalite composition and of olivine shape and distribution. Samples have been optically imaged and then mapped EDS using a JEOL JSM-6500F field-emission SEM equipped with an Oxford X-Max 80 mm 2 silicon drift detector to determine major element composition and distribution. The Oxford AZtec software allows large-format montaged mapping so that the entire specimen can be mapped to the same scale. Smaller region EDS mapping highlights minor mineral phases and the interfaces between the mineral grains and the metal phases. These maps quantitatively verify the mineral phases present and the Fe/Mg ratio of the olivine phase and the Fe/Ni ratio of the metal phase. Electron microprobe WDS analyses of mineral phases are being done on a JEOL 8900 to verify major and minor element composition in regions of interest. These analyses also highlight areas that are targeted for focused ion beam (FIB) analysis. The FIB is used to examine the interface between olivine and metal and create a 3-D reconstruction. Nano-scale phases are then highlighted for future TEM preparation. Between the SEM and microprobe results, areas were highlighted for mass spectrometry analysis. Several samples were analyzed with laser ablation ICPMS for trace element content. Pallasites can provide information about highly-siderophile elements (HSE) present in both mantle and core of differentiated bodies. Many differentiated planetary bodies show enrichment in HSE concentration in their mantle relative to their core. Our study indicates that both HSE concentrations and the O-isotope fractionation share a common trend with iron III-AB meteorites. The HSE concentrations are also comparable to Mars and the Angrite parent body. In addition, diffusion profiles are being obtained in the microprobe for both the metal and olivine phases, which indicate the cooling rates of these meteorites. The iron metal region contains regions of taenite interlaced with kamacite, in which Ni zonation and diffusion has traditionally been used to determine the metallographic cooling rate within the taenite [1]. More recently, zonation of the olivine rim has been used to determine cooling rates [2], however these indicate a much faster cooling rate than that estimated by the metallic rates. This study aims to examine diffusion in both phases to better

Calibration of relative sensitivity factors for impact ionization detectors with high-velocity silicate microparticles

Impact ionization mass spectrometers, e.g., the Cosmic Dust Analyzer (CDA) onboard the Cassini spacecraft can quantitatively analyze the chemical composition of impacting particles, if the ionization efficiencies of the elements to be quantified are appropriately calibrated. Although silicates are an abundant dust species inside and outside the Solar System, an experimental calibration was not available for elements typically found in silicates. We performed such a calibration by accelerating orthopyroxene dust of known composition with a modified Van de Graaff accelerator to velocities of up to 37.9kms−1 and subsequent analyses by a high resolution impact ionization mass spectrometer, the Large Area Mass Analyzer (LAMA). The orthopyroxene dust, prepared from a natural rock sample, contains ∼90% orthopyroxene and ∼10% additional mineral species, such as clinopyroxene, spinel, amphibole, olivine and glasses, which are present as impurities within the orthopyroxene, due to inclusion or intergrowth. Hence, the dust material can be regarded as a multi-mineral mixture. After analyses, we find that most particle data cluster at a composition ascribed to pure orthopyroxene. Some data scatter is caused by stochastic effects, other data scatter is caused by the chemically different mineral impurities. Our data indicate that these minor mineral phases can be recognized within a multi-mineral mixture. Here, for the first time, we present experimentally derived relative sensitivity factors (RSFs) for impact ionization mass spectroscopy of silicates, enabling the quantitative determination of the composition of cosmic dust grains. Orthopyroxene data were used to infer RSFs for Na, Mg, Al, Si, Ca, Ti, Fe and K, for particles with radii ranging from 0.04μm to 0.2μm and velocities between 19 and 37.9kms−1, impacting on a Rh-target.

Minor nutrients are critical for the improved growth of Corylus avellana shoot cultures

Many hazelnut (Corylus avellana L.) cultivars fail to thrive in vitro on standard growth medium and the reasons for poor growth are not well understood. Our initial study of five C. avellana cultivars showed that changes in the mineral nutrients of Driver and Kuniyuki walnut (DKW) medium, including doubling the minor nutrients, produced improved growth and shoot quality. The objectives of this study were to determine the effects of the individual minor mineral nutrients from DKW medium and if added nickel was required for optimal growth. Five factors were tested at 0.5 × to 4× DKW medium concentrations, [H3BO3, CuSO4·5H2O, MnSO4·H2O, Na2MoO4·2H2O and Zn(NO3)2·6H20], in a response surface design with 39 treatment combinations. Ni was not present in the DKW medium formulation so NiSO4·6H2O was varied from 0 to 6 µM. There were many significant interactions among the minor nutrients. Higher concentrations (4×) of B, Mo, and Zn increased overall shoot quality, length, and multiplication. Increased Mo improved some responses for each cultivar, and it interacted significantly with Cu and Zn. The addition of Ni greatly improved the shoot quality and length of ‘Sacajawea.’ Ni interactions were significant for the other cultivars as well, and altered the requirements for the other minor nutrients, but did not necessarily improve the overall shoot response. Improved growth and shoot quality for most cultivars required increased amounts of B, Mo, and Zn and less Mn and Cu. ‘Sacajawea’ required increased B, Cu, Zn, and Ni. All of the cultivars required minor nutrient formulations that differed greatly from DKW medium or other published minor nutrient formulations.

Re-evaluating digestion methods for highly siderophile element and 187Os isotope analysis: Evidence from geological reference materials

Here we evaluate measurement procedures currently used for the combined determination of highly siderophile element concentrations (HSEs: Re, Ir, Os, Ru, Pt and Pd) and Os isotope ratios in geological samples by isotope dilution mass spectrometry (ID-MS) applying high-temperature sample digestion using inverse aqua regia in closed glass vessels, such as Carius tubes or a high-pressure asher system (HPA). In particular, we address the question of whether an additional hydrofluoric acid dissolution step is required to release HSEs hosted in the silicate portions of rock samples. To do so, we conducted systematic experiments for basaltic (TDB-1 and BIR-1), ultramafic (UB-N and JP-1) and sedimentary (SCo-1, SDO-1 and JCh-1) reference materials with and without HF desilicification. Through the extensive tests on TDB-1—varying apparatus (microwave, Carius tube, high-pressure asher), conditions (temperature, duration, sample size) and protocol (HF desilicification before or after aqua regia attack)—we find the optimum digestion method is to use inverse aqua regia for digesting 1–2g of powder over long durations, such as Carius tubes heated to 240˚C for 72h, followed by an HF desilicification step after CCl4 solvent extraction of Os. For basaltic reference materials, the method provides significantly improved HSE recoveries—particularly Ru—largely due to the use of HF. Strong linear correlations between Os and Ir–Ru–Pt concentrations and isochronous behavior on a 187Re/188Os vs. 187Os/188Os diagram (1240±59Ma, MSWD=1.4) are observed for repeat dissolutions of TDB-1, reflecting sample heterogeneity due to minor minerals enriched in Os, Ir, Ru and Pt—most likely sulphides. In comparison, excellent reproducibilities were obtained for BIR-1: relative standard deviations (RSDs) for 1–2g aliquots were 6.9% Os, 5.1% Ir, 2.0% Ru, 5.1% Pt, 1.5% Pd and 0.7% Re (n=9). Thus, BIR-1 might be a useful candidate reference material for obtaining certified values with small measurement uncertainties. Unlike the basaltic reference materials, extraction of HSEs from ultramafic and sedimentary reference materials is largely independent of the use of HF. The data obtained by Carius tube for UB-N and JP-1 agree well with the literature data obtained using apparently more aggressive digestion techniques. The precision of our data for 0.5–2g aliquots of the sedimentary reference materials also compares favourably with limited data available in the literature.