High Fo Research Articles

Multi-stage kimberlite evolution tracked in zoned olivine from the Benfontein sill, South Africa

Olivine is the dominant mineral present in kimberlite magmas; however, due to the volatile-rich nature of most kimberlites, they rarely survive late-stage serpentinisation. Here we present major and trace element data for a rare example of ultra-fresh olivine in a macrocrystic calcite kimberlite from the Benfontein kimberlite sill complex. Olivines are characterised by xenocrystic cores surrounded by multiple growth zones representing melt crystallisation and late-stage equilibration. Two distinct core populations are distinguished: Type 1) low Fo (88–89), Ni-rich, Ca- and Na-rich cores, interpreted here to be the result of carbonate–silicate metasomatism potentially as part of the earliest stages of kimberlite magmatism, and Type 2) high Fo (91–93), Ni-rich, low-Ca cores derived from a typical garnet peridotite mantle source. In both cases, the cores have transitional margins (Fo89–90) representing equilibration with a proto-kimberlite melt. Trace element concentrations, in particular Cr, of these transition zones suggest formation of the proto-kimberlite melt through assimilation of orthopyroxene from the surrounding garnet peridotite lithology. Trace element trends in the surrounding melt-zone olivine (Fo87–90) suggest evolution of the kimberlite through progressive olivine crystallisation. The final stages of olivine growth are represented by Fe-rich (Fo85) and P-rich olivine indicating kimberlite evolution to mafic compositions. Fine (<60μm), Mg-rich olivine rims (Fo94–98) represent equilibration with the final stages of kimberlite evolution back to Fe-poor carbonatitic melts.We present a step-by-step model for kimberlite magma genesis and evolution from mantle to crust tracked by the chemistry of olivines in the Benfontein kimberlite. These steps include early stages of metasomatism and mantle assimilation followed by direct crystallisation of the kimberlite melt and late-stage equilibration with the evolved carbonatitic residual liquids. The Ca contents of the Type 1 xenocrystic olivines are the highest yet measured for mantle olivines, and do not overlap with any known mantle xenolith lithologies. These olivines likely represent an important stage of metasomatism directly related to the early stages of kimberlite melt ponding at the base of the lithospheric mantle.

Recent developments in forward osmosis membrane bioreactors: a comprehensive review

Forward osmosis or osmotic membrane bioreactor (FOMBR) has attracted great attention for wastewater treatment and reuse since conceptually introduced as a process. It has been proposed to reduce the high energy consumption in the conventional MBR, has lower membrane fouling propensity, and produce higher quality water. Moreover, RO process can be used after FOMBR to reconcentrate the diluted DS to be used for FO again. Besides significant advantages, when compared to conventional MBRs; lower water flux, concentration polarization, and salt accumulation because of high retention of FO in the bioreactor still remains as major drawbacks and challenges of FOMBR systems that need to be solved. In the last few years, many advances in development of FOMBR are stated to overcome the drawbacks of the system. The researches focused on manufacturing of high performance FO membranes and orientation, utilizing various different draw solutions providing required osmotic pressure and minimum reverse salt flux, and recently hybrid systems to alleviate the salt accumulation in bioreactor. However, the main critical challenges of FOMBR have not been completely resolved yet. This paper reviews the design and applications of FOMBR process in wastewater treatment. Particular focus was given to reverse salt flux and effects of the system performance; recent developments in FOMBR applications from beginning till today are reported.

ChemInform Abstract: Chemistry of InP Nanocrystal Syntheses

AbstractReview: 130 refs.

Chemistry of InP Nanocrystal Syntheses

Chemically synthesized InP nanocrystals (NCs) are drawing a large interest as a potentially less toxic alternative to CdSe-based nanocrystals. With a bulk band gap of 1.35 eV and an exciton Bohr radius of ∼10 nm the emission wavelength of InP NCs can in principle be tuned throughout the whole visible and near-infrared range by changing their size. Furthermore, a few works reported fluorescence quantum yields exceeding 70% after overcoating the core NCs with appropriate shell materials. Therefore, InP NCs are very promising for use in lighting and display applications. On the other hand, a number of challenges remain to be addressed in order to progress from isolated research results to robust and reproducible synthesis methods for high quality InP NCs. First of all, the size distribution of the as-synthesized NCs needs to be reduced, which directly translates into more narrow emission line widths. Next, reliable protocols are required for achieving a given emission wavelength at high reaction yield and fo...

Frequency Characteristics in Animal Species Typically Used in Laryngeal Research: An Exploratory Investigation

Laryngeal research is typically conducted on animal species that have similar features to the human larynx, yet little is known of the frequency characteristics of those animals. This study examines frequency characteristics of dog, cat, pig, and sheep across emotional communication events. Prospective study. Acoustic data were gathered in domestic environment, with fundamental frequency (fo) computation of vocalization during happy, distress, and food request activities. Dogs demonstrated reduced fo range and reduced vocalization as a factor of age (18 semitones for adult male dog, three semitones for aged male dog). When two barks were present, the second bark was typically shorter in length and had a higher fo. Male cat was observed to be more talkative and exhibited a much higher purr fo than his female housemate. Cat purr was varied by sex between the typical 25 Hz and a significantly higher fo, consistent with literature on use of cry-purr by some cats. Lambs exhibited phonation breaks, and an overall frequency range of 28 semitones in lambs compared with 49 semitones for mature sheep. Piglets exhibited fo range of 44 semitones with higher fo with distress and lowest fo for grunting. Aged animals followed similar phonatory patterns of humans, with change of fo for communication need. The male cat was found to purr differently from female cats. Pigs and cats may have nonlaryngeal source signal coupling. Animal phonation changes with emotion. Observed fo patterns may improve interpretation of phonation among laboratory animals in laryngeal research.

Petrogenesis of orogenic lamproites of the Bohemian Massif: Sr–Nd–Pb–Li isotope constraints for Variscan enrichment of ultra-depleted mantle domains

During convergence of Gondwana-derived microplates and Laurussia in the Palaeozoic, subduction of oceanic and continental crusts and their sedimentary cover introduced material of regionally contrasting chemical and isotopic compositions into the mantle. This slab material metasomatised the local mantle, producing a highly heterogeneous lithospheric mantle beneath the European Variscides. The eastern termination of the European Variscides (Moldanubian and Saxo-Thuringian zones of Austria, Czech Republic, Germany and Poland) is unusual in that the mantle was modified by material from several subduction zones within a small area. Orogenic lamproites sampled this lithospheric mantle, which has a chemical signature reflecting extreme depletion (low CaO and Al2O3 contents and high Mg-number) followed by strong metasomatic enrichment, giving rise to crust-like trace element patterns, variable radiogenic 87Sr/86Sr(330) (0.7062–0.7127) and non-radiogenic Nd isotopic compositions (εNd(330)=−2.8 to −7.8), crustal Pb isotopic compositions, and a wide range of δ7Li values (−5.1 to +5.1). This metasomatic signature is variably expressed in the lamproites, depending on the extent of melting and the nature of the source of the metasomatic component. Preferential melting of the metasomatically enriched (veined) lithospheric mantle with K-rich amphibole resulted in lamproitic melts with very negative, crust-like δ7Li values, which correlate positively with peralkalinity, HFSE contents and lower εNd. Both the higher degree of melting and progressive consumption of the metasomatic component reduce the chemical and isotopic imprints of the metasomatic end member. The very positive δ7Li values of some lamproites indicate that the source of these lamproites may have been modified by subducted oceanic lithosphere. Fresh olivine from the Brloh (Moldanubian) lamproitic dyke shows very high Fo (up to 94%) and very high Li contents (up to 25ppm), demonstrating that the extremely depleted and later enriched lithospheric mantle may have contributed significantly to the Li budget of the lamproites. The regional distribution of lamproites with contrasting chemical and isotopic fingerprints mimics the distribution of the different Variscan subduction zones.

Fabrication of carbon nanotubes incorporated double-skinned thin film nanocomposite membranes for enhanced separation performance and antifouling capability in forward osmosis process

Novel carbon nanotubes (CNTs) incorporated double-skinned thin film nanocomposite (TFN) membranes were fabricated by interfacial polymerization of polydopamine/CNTs and trimesoylchloride (TMC) on polysulfone (PSf) substrate. As controls, thin film composite (TFC) membrane without CNTs and FO membranes with single-skinned structures (top-skinned or bottom-skinned) was also fabricated. The prepared membranes were characterized and evaluated in terms of membrane morphology, structure, surface property, separation performance and antifouling capacity. The effect of membrane orientation, composition and concentration of draw solutions on FO performance was studied as well. It was found that CNTs had significant influence on the properties and the performances of the synthesized FO membranes. The double-skinned membranes owned excellent solute rejection without sacrificing water flux. By incorporation of CNTs, TFN membranes exhibited higher FO water flux than TFC membranes. The double-skinned TFN0.05 membrane, the optimal FO membrane, showed a 54% enhancement in water flux than double-skinned TFC membrane at TOP-FS orientation by using MgCl2 as draw solution and DI water as feed solution. Moreover, the double-skinned TFN0.05 membrane demonstrated remarkable antifouling capacity because of the prominent foulant resistance induced by CNT addition. This work paved a new way to fabricate high performance FO membrane by the utilization of double-skinned structure and incorporation of CNTs.

Routine arterial blood gas analysis for monitoring of carbon dioxode elimination during high frequency jet ventilation fo r prolonged laryngeal microsurgery: is it still necessary?

High frequency jet ventilation is a method of choice for most of the endolaryngeal procedures as it allows unimpaired view of larynx and can be delivered via small catheters. Howe ver, despite improved oxygenation, elimination of carbon dioxide may be significantly affected and patients’ СО 2 status has to be monitored strictly. Although capnography provides adequate information regarding the efficiency of carbondioxide elimination, for relatively long procedures arterial blood sampling may be required. We report a retrospective study of 35 patients who had undergone microlaryngeal surgery for bilateral vocal cord paralysis performed under general anesthesia with subglottic high frequency jet ventilation. Duration of surgical interventions exceeded 90 min in all cases. Comparative analysis of different CO 2 monitoring methods shows nopreferences of arterial blood gas analysis over capnography. Obtained data suggest that noninvasive CO 2 monitoring methods provide adequate information for correct setting of jet ventilator parameters during prolonged microlaryngeal surgery.

熊本県阿蘇市上米塚産スコリアのかんらん石斑晶における鉄酸化数と噴出後の高温酸化の影響

The chemical compositions and oxidation states of Fe in olivine phenocrysts in scorias from Kami-Kometsuka, Aso, Kumamoto Prefecture, Japan, were analyzed to evaluate effect of high temperature oxidation on the scoria. The rocks in the interior of the Kami-Kometsuka scoria cone are red-brown and weakly welded, whereas black scoria occurs on the upper zone of the cone. Olivine phenocrysts within the black scoria lack precipitate minerals, but those exposed on the voids contain small amounts of precipitates at their rims. Olivine phenocrysts in the red-brown scoria contain abundant cryptocrystalline precipitates including hematite, magnetite and enstatite. Olivines in the black scoria have normal zoning with Fo87 cores and Fo68 rims and reverse zoning with Fo66 cores and Fo70 rims, whereas those in the red-brown scoria reach 99 mol% Fo. By applying the relationship between FeLβ/FeLα-intensity ratios and Fe3+/∑Fe, the Fe3+/∑Fe of the olivine phenocrysts in the black scoria were determined to be 0-1(2)% at the cores and 3(2)% at the rims. The Fe3+ at the rims of the olivine phenocrysts in the black scoria and the cryptocrystalline precipitates and extremely high Fo contents within olivine phenocrysts in the red-brown scoria are due to high temperature oxidation.

Petrogenesis of the Xuanwoling mafic–ultramafic intrusion in the northeastern Tarim Block (Northwest China)

Beishan Terrane, located in the northeast of the Tarim Block, in northwest China, has developed a 500-km long and 100-km wide belt of Permian mafic–ultramafic intrusions. One of these mafic–ultramafic intrusions, the Xuanwoling Intrusion, is composed of dunite, troctolite, olivine gabbros, and gabbros, with cumulate texture and rhythmic layering. The crystallization sequence is olivine + spinel → plagioclase → pyroxene, indicating that the crystallization pressure is lower than 0.5–0.8 GPa and that the intrusion has undergone variable degrees of crustal contamination, increasing from dunite to gabbros. The olivines found in the Xuanwoling Intrusion have high Fo values (up to 90), suggesting a primary magma with a high composition of mg. It is likely that this high-mg magma was produced at extremely high temperatures (1,330–1,350 °C), and as a result, Nd–Sr isotopic compositions similar to oceanic island basalts are found in the Xuanwoling Intrusion, which we propose arose from the mantle plume.

N-Doping-Induced Nonradical Reaction on Single-Walled Carbon Nanotubes for Catalytic Phenol Oxidation

Metal-free materials have been demonstrated to be promising alternatives to conventional metal-based catalysts. Catalysis on nanocarbons comparable to that of cobalt- or manganese-based catalysts in peroxymonosulfate (PMS) activation has been achieved, yet the catalyst stability has to be addressed and the mechanism also needs to be elucidated. In this study, N-doped carbon nanotubes (NoCNTs) were employed as metal-free catalysts for phenol catalytic oxidation with sulfate radicals and, more importantly, a detailed mechanism of PMS activation and the roles of nitrogen heteroatoms were comprehensively investigated. For the first time, a nonradical pathway accompanied by radical generation (•OH and SO4•–) in phenol oxidation with PMS was discovered upon nitrogen heteroatom doping. The NoCNTs presented excellent stability due to the emerging nonradical processes. The findings can be used for the design of efficient and robust metal-free catalysts with both superior catalytic performance and high stability fo...

Effects of Fusarium oxysporum on rhizosphere microbial communities of two cucumber genotypes with contrasting Fusarium wilt resistance under hydroponic condition

Two cucumber genotypes were chosen that differ in Fusarium wilt resistance and inoculated with Fusarium oxysporum (Schlechtend, Fr) f. sp. cucumerinum (Owen) Snyder & Hansen (FO) in a hydroponic nutrient solution system to determine whether differences in plant genotype affected rhizosphere microbial community and its involvement in resistance to root-borne pathogens. Response of the FO population and microbial communities were compared in the nutrient solution and on root surfaces. Results demonstrated that FO inoculation resulted in a higher FO population on root surfaces and a lower population in the nutrient solution for the susceptible genotype JinYan NO. 4 (JYan); however, an inverse pattern was observed in the resistant JinYou NO. 1 (JYou). Similarly, promotive effects on FO spore germination and germ-tube elongation were only observed in root exudates from FO-inoculated susceptible JYan. FO inoculation resulted in overall increases in cultivable fungi and oomycetes, and actinomycete populations on root surfaces of the resistant JYou compared to the JYan counterpart. PCR-DGGE analysis of 16S rDNA fragments indicated that following FO inoculation, significant changes in the bacterial structure isolated from the root surfaces of susceptible plants were observed, such as an increased diversity index, a decreased evenness index, and the occurrence of several types of bacteria that decomposed organic substances. These results suggest that a complex interaction between plant genotypes and pathogen affected the rhizosphere microbial community.

Petrogenesis of dunites from Gibbs Island, South Shetland Islands, Antarctica

We determined mineral and Sr-Pb isotopic compositions in a dunite complex from Gibbs Island, South Shetland Islands, Antarctica, to understand its petrogenesis. Gibbs dunites consist mainly of refractory olivines (Fo93.4–95.2) with minor chromite spinels (Cr# = 84.2–89.2). The high Fo (93.4–95.2), low CaO (<0.02 wt%) and high NiO (0.4–0.6 wt%) contents of its magnesian olivine indicate that it originated in residual mantle rather than cumulates. The highly refractory olivine and spinel compositions resemble those found in fore-arc dunites. Estimated olivine-spinel Mg-Fe2+ equilibrium temperatures for the Gibbs dunites range from 580 °C to 780 °C, which is lower by ca. 100 °C than abyssal peridotites, in general, but within the range of fore-arc peridotites and dunites. On the Pb-Pb and Sr-Pb isotopic covariation diagrams, Gibbs dunites plot off the field defined by mid-ocean ridge basalts and extend into the fields for modern seawater or pelagic sediments. These data, together with elevated Th/La ratio, suggest that the Gibbs dunites are likely to be a suprasubduction zone mantle origin.

The Erbutu Ni-Cu Deposit in the Central Asian Orogenic Belt: A Permian Magmatic Sulfide Deposit Related to Boninitic Magmatism in An Arc Setting

The Erbutu Ni-Cu sulfide deposit is hosted in a small ultramafic intrusion located at the southern margin of the Central Asian orogenic belt, Inner Mongolia. This deposit is the first case of a magmatic sulfide deposit related to boninitic magmatism in an arc setting. The host intrusion is composed of orthopyroxenite and olivine orthopyroxenite. More than three quarters of the intrusion contains economic, disseminated sulfide mineralization. SHRIMP U-Pb dating of zircons from the intrusion gives a crystallization age of 294.2 ± 2.7 Ma, similar to the age of the Permian Tarim plume in northwest China. Olivine orthopyroxenite is characterized by olivine crystals with relatively high Fo contents (85–88 mol %) and extremely low Ca contents (<250 ppm). Coexisting orthopyroxene crystals have clinoenstatite composition with enstatite from 86 to 88 mol %. Whole-rock data show characteristic enrichments of light REE relative to heavy REE, pronounced negative Nb-Ta anomalies, and moderately positive Hf anomaly. The δ 34S values of sulfide separates are 4 to 5‰, significantly higher than the typical mantle value (0 ± 2‰). The ɛ Hf values of zircons are from −4 to −9. These data indicate that the parental magma was a boninite. Crustal contamination was involved during magma evolution and ore formation.

HEPATOBILIARY DISORDERS IN CHILDREN CHRONICALLY EXPOSED TO PHENOL AND FORMALDEHYDE

Background. Adults with aerogenic exposure to formaldehyde (Fo) and phenol (Fen) demonstrate morphological and functional hepatobiliary disorders. In children, Fo and Fenimpact on the hepatobiliary system has not been studied well. Aims. To assess the characteristics of hepatobiliary disorders in children with chronic aerogenic Fen and Fo exposure. Methods. Astudy group (1) included 200 children aged 4-7 years with reactive hepatobiliary disorders and chronic aerogenic Fen and Fo exposure.A control group (2) consisted of 102 children who had no Fen and Fo exposure. Results.Group 1 resided in the area with high Fen and Fo concentrations in ambient air (average daily concentrations up to 0.011mg/m3 and 0.007mg/m3, respectively, the highest concentrations up to 0.024mg/m3 and 0.061mg/m3, respectively). Health HQ was 1.66 (Fen) and 2.82 (Fo),total HIfor both Fen and Fo for liver pathology development was 1.88, the contribution of Fen to the development of hepatobiliary pathologywas 88.3%. In group 1, blood samples containedhigh Fen (0.047±0.008 mg/dm3) and Fo (0.012±0.002 mg/m3) levels. In group 2, these values did not exceed the background levels. We detected changes in laboratory parameters – a 1.2-fold reduction in antioxidant activity (AOA) compared with group 2, a 1.2-fold increase inplasma malondialdehyde (P-MDA), hypoalbuminemia in 68% (group 1) and in 12% (group 2) (p=0.05), increased direct bilirubin (DB) (56% vs 28%, p=0.02 to 0.05), elevated total cholesterol (48% vs 18%, p=0.03), increased ALT (36% vs 7%, p=0.02) and AST(76% vs 21%, p=0.04). We determined cause-and-effect relationships between blood Fo levels and increasedDB (R2=0.34; p=0.049), ALT and AST (R2=0.34; p=0.042 and R2=0.513; p=0.024), between blood Fen levels and P-MDA (R2=0.2; p=0.041), AOA (R2=0.29; p=0.037). Conclusions. Hepatobiliary disorders associated with Fen and Fo exposure are accompanied by impaired redox homeostasis, lipid and pigment metabolism and by the cytolysis syndrome.

The New Cosmology Rrising from the Quantum Pushing Gravity Interaction—The Case of Accelerating Universe

In 2011 three astronomers were awarded the Nobel Prize for Physics having focussed a correct method of measuring cosmic distances by observation of far Supernovae Ia. Assuming the 'lambda’CDM expanding model, they showed that part of the Universe was accelerating, contrary to the original General Relativity predictions. The acceleration was attributed to an Obscure energy linked to the cosmological constant L. This constasnt was formerly introduced by Einstein in the original G.R. equations to empirically counterbalance the gravitational force to the aim of describing the (known) static universe. After the Hubble’s discovery (1929) of galaxy redshifts, which launched the expanding universe, Einstein rejected L. This was the sign that he considered L a provisional parameter, not the expression of a new physical force. Nevertheless, this parameter is till today taken into account by cosmologists to fit their observations through the LCDM model. Something is not consequent in the history of the Gravitational theory. The “accelerated expansion” of the universe can be firmly established only through a model independent way. In fact the SNe distances calculated by LCDM expanding model resulted so large that part of the SNe exploded before the so called Big bang Age, in contrast with the bases of the expansion. The astronomers appear reluctant to claim this splashing result. Something in the Obscure energy is not convincing. Before knowing the astronomer’s work, I carried out a research about the physical inadequacy of General Relativity as proper theory of Gravitation, notwithstanding the great success in astronomical observations. The profound reason of this inconsistency is the absence of interaction-waves, contrarily to other fundamental Interactions considered in the Standard Model. From several decades the research attempted to improve this unsatisfactory situation trying to detect the so called gravitational waves coming from cosmic events, but no tangible results have been obtained yet. Actually, the gravitational-inertial waves surely exist, as well as the measured gravitational force. The wavelength I found is of the order of the Planck’s length, so adequate tools are necessary for detection. One year ago I published a comprehensive analysis which, recognising the inadequacy of the old kinematic basis of Special relativity, gave rise (Michelini, 2012) to a Relativistic Dynamics re-founded on the new dynamical basis of the Micro-quanta paradigm. The high flux fo of micro-quanta filling the space originates, through the mutual-shielding between two particles/masses, the Quantum Pushing gravitational force, whereas at very short distances (<10-15) the same flux fo generates the Strong and Weak nuclear forces. Contrarily to the old Newton’s ideas, all these drawing forces do not pull the particles, but push them each other, thus giving rise to the process of Unification of forces. The present paper deals in particular with the Quantum Pushing Gravitation operating on large distances (cosmology), so that between two very distant masses the effect of the mutual scattering on the interposed micro-quanta is not negligible, giving rise to an attenuation factor on the gravitational constant. Quantum Pushing gravitation defines a variable G(r) = G exp(–Sor) showing that parts of Universe at cosmological distances? do not feel sensibly the gravitational force. Then the Universe results static, i.e. not expanding. The observed high Hubble’s redshifts depend on the interaction of photons that travelled across the micro-quanta giving rise to the redshift z(x) = exp(x/Lo) –1. The SNe measuring method just discovered exponentially increasing redshifs. Trying to explain this fact, the redshfts were introduced in the LCDM expanding model that produced the large distances resembling an accelerating universe. Several SNe resulted to exist well before the Big bang. Considering this contrast, which inhibits the expanding models, we introduced the observed SNe redshifts in the Static model, finding that the last SNa (z = 1.91) explosion happened 15 Gys ago, a reasonable result. Attributing the Hubble’s redshift to the Doppler appears no longer necessary. The static universe, immersed within the micro-quanta, is obviously evolving because the synthesis of heavy nuclei always occurs within the star cores. No arbitrary constant L has to be introduced in the Static model since the erroneous concept of “gravitational” mass has been previously eliminated through the Quantum Pushing gravity. The main proof of the Static model is the quantitative recognition that the observed Cosmic Microwave Background is due to redshifted photons emitted–with the characteristic black body spectrum–from all stars of the universe.

Discerning crystal growth from diffusion profiles in zoned olivine by in situ Mg–Fe isotopic analyses

Mineral zoning is used in diffusion-based geospeedometry to determine magmatic timescales. Progress in this field has been hampered by the challenge to discern mineral zoning produced by diffusion from concentration gradients inherited from crystal growth. A zoned olivine phenocryst from Kilauea Iki lava lake (Hawaii) was selected for this study to evaluate the potential of Mg and Fe isotopes for distinguishing these two processes. Microdrilling of the phenocryst (∼300μm drill holes) followed by MC-ICPMS analysis of the powders revealed negatively coupled Mg and Fe isotopic fractionations (δ26Mg from +0.1‰ to −0.2‰ and δ56Fe from −1.2‰ to −0.2‰ from core to rim), which can only be explained by Mg–Fe exchange between melt and olivine. The data can be explained with ratios of diffusivities of Mg and Fe isotopes in olivine scaling as D2/D1=(m1/m2)β with βMg ∼0.16 and βFe ∼0.27. LA-MC-ICPMS and MC-SIMS Fe isotopic measurements are developed and are demonstrated to yield accurate δ56Fe measurements within precisions of ∼0.2‰ (1 SD) at spatial resolutions of ∼50μm. δ56Fe and δ26Mg stay constant with Fo# in the rim (late-stage overgrowth), whereas in the core (original phenocryst) δ56Fe steeply trends toward lighter compositions and δ26Mg trends toward heavier compositions with higher Fo#. A plot of δ56Fe vs. Fo# immediately distinguishes growth-controlled from diffusion-controlled zoning in these two regions. The results are consistent with the idea that large isotopic fractionation accompanies chemical diffusion in crystals, whereas fractional crystallization induces little or no isotopic fractionation. The cooling timescale inferred from the chemical-isotope zoning profiles is consistent with the documented cooling history of the lava lake. In the absence of geologic context, in situ stable isotopic measurements may now be used to interpret the nature of mineral zoning. Stable isotope measurements by LA-MC-ICPMS and MC-SIMS can be used as standard petrologic tools to identify samples for diffusion-based geospeedometry.

Fundamental frequency as cue to intonation: Focus on Ika Igbo and English rising intonation patterns

This paper shows that fundamental frequency, Fo, can be a cue to type of intonation. The work centers on three main intonation patterns in Ika Igbo and English. Ika Igbo is a language that manifests intonation in addition to lexical tone. These intonation patterns are Low Rise (LR), High Rise (HR) and Fall Rise (FR). The Fos of these intonation patterns were analyzed acoustically in utterances with similar phonemes and tunes in both languages. Eighteen utterances were used for the study. The analyses show that the Fos of LR and FR intonation were generally lower than those of HR. Hence it can be concluded that high intonation has high Fo while low intonation has low Fo. It can therefore be concluded that Fo is a cue to type of intonation.

Origin of ultra-nickeliferous olivine in the Kevitsa Ni–Cu–PGE-mineralized intrusion, northern Finland

The 2,058 ± 4 Ma mafic-ultramafic Kevitsa intrusion is located in the Central Lapland greenstone belt, northern Finland. It is hosted by a Paleoproterozoic vol- cano-sedimentary sequence that contains komatiitic vol- canic rocks and sulfide- and graphite-rich black schists. Economic Ni-Cu-(PGE) sulfide mineralization occurs in the middle part of the ultramafic lower unit of the intrusion. Two main types of ore are distinguished, ''normal'' and ''Ni-PGE'' ores. The normal ore is characterized by * 2t o 6 vol% disseminated sulfides and average Ni and Cu grades of 0.3 and 0.42 wt %, respectively (Ni/Cu \ 1). The Ni- PGE ore has broadly similar sulfide contents, but a higher Ni grade and lower Cu grade. As a result, the Ni/Cu ratio reaches 15, much higher than in the normal ore. The Ni- PGE ores occur as irregular, discontinuous, lense-like bodies in the ultramafic rocks. Notably, the olivines in the Ni-PGE ore contain extremely high Ni contents of up to 14,000 ppm, which is significantly higher than the Ni content of olivine in other mafic-ultramafic igneous rocks globally (up to *5,000 ppm) and in harmony with the associated Ni-rich sulfide assemblage containing pent- landite, millerite and pyrite. Microprobe mapping of olivine from the Ni-PGE ore suggests relatively low and homogeneous S contents and homogeneous distribution of Ni, Mg, Fe, which is inconsistent with the presence of sulfide inclusions in the olivine grains, or diffusion of Ni from interstitial sulfides into the olivine grains. We there- fore conclude that Ni substitutes for Mg in the olivine lattice. The clinopyroxenes from the Ni-PGE ore also have unusually high Ni concentrations reaching 1,500 ppm and show a positive correlation with the nickel content of the associated olivine. The Nicpx/Niolivine is *0.1 to 0.2 cor- responding to high T partitioning of Ni between clinopy- roxene and olivine. KD of 20 can account for the partitioning of nickel between olivine and the sulfide phase, consistent with magmatic equilibration. These data suggest that the olivine, clinopyroxene, and sulfides all crystallized from a basaltic magma with an unexceptionally high Ni content ranging from 300 to 1,100 ppm. The Ni-PGE ores are spatially associated with ultramafic xenoliths. Olivine in these ultramafic xenoliths have relatively high Fo con- tents (up to 90 mol %) and high Ni contents (up to 5,200 ppm) suggesting that the xenoliths formed from a komatiitic parental magma. It is proposed that assimilation by the Kevitsa magma of massive or semi-massive sulfides associated with komatiitic rocks elevated the Ni content of the magma and resulted in the formation of Ni-PGE ores and related extremely Ni-rich olivines.

Sulfide-rich dunite within a thick Moho transition zone of the northern Oman ophiolite: Implications for the origin of Cyprus-type sulfide deposits

Peculiar dunites, in part wehrlitic, that contain up to 3vol.% sulfides from a thick (~1000m) Moho transition zone (MTZ) are found along Wadi Thuqbah in the northern Oman ophiolite. We discuss their relevance to the formation of Cyprus-type massive sulfide deposits near the surface. Field observations suggest that the sulfide-rich MTZ dunites are of late-intrusive origin. The sulfides form composite grains with magnetite and form angular clasts, which are enclosed or cut by magnetite. The sulfide part is composed of homogeneous pyrrhotite and vermicular intergrowth of pyrrhotite and pentlandite. Sulfide inclusions in clinopyroxene comprise pyrrhotite with pentlandite blebs, free of magnetite. Olivines in the sulfide-rich dunite characteristically show low NiO contents (0.1–0.3wt.%) relative to a high Fo value (~91), and as such they do not lie on a Fo–NiO trend of ordinary sulfide-free MTZ dunites–wehrlites. This low-Ni olivine was precipitated from a high-Mg magma that had segregated Ni-rich sulfide melts. The pentlandite–pyrrhotite intergrowth was formed by subsolidus exsolution at low temperatures (<200°C) from high-temperature mono-sulfide solid solution. Iron released from olivine during serpentinization produced magnetite, which was combined with the sulfides to form the composite grains. In-situ S isotope ratios of the sulfides (δ34S=0.7–2.8) are slightly higher than mantle values but lie within the range for magmas from oceanic island arcs, such as the Marianas. The δ34S are lower than those for sulfate from seawater and MORB-related sulfides, such as TAG (Trans-Atlantic Geotraverse) deposits. One of the Cyprus type massive sulfide deposits (Aarja) from the crustal section of the same area shows similar S isotope ratios to the sulfides in the Thuqbah sulfide-rich dunites/wehrlites, indicating their genetic linkage. The Aarja sulfide deposit was formed within the V2 lavas, which are relatively sulfur-rich and of an off-axis origin, as a result of high-temperature seawater circulation. The Thuqbah sulfide-rich dunite possibly represents an igneous root of the Cyprus-type massive sulfide deposit of Aarja formed in an off-ridge magmatic-hydrothermal system.