Trace Elements Ti Research Articles

Middle Triassic Limestones as a Source of Trace Elements and REY.

The results of the content determination of the selected trace elements Ti, Sr, Ba, Zn, Pb, Cu, S, P, Cr, Cd, Ni, Zr, Mo, Rb, Sc, Y, and REEs were presented in this article. Studies were carried out to define the purity of limestones. The elements were measured in the carbonate minerals of Middle Triassic limestones of the Opole Silesia in Poland, using ICP-MS and X-ray fluorescence (XRF). Moreover, the contents of Sc and REY were also determined by electron microprobe analysis. These methods are characterized by high accuracy and precision of the measurement. The research results show that the contents of trace elements vary from below 1 ppm up to some hundreds ppm. The highest content was measured for strontium and the lowest for barium, elements characteristic of aragonite. Their occurrence indicates the presence of aragonite in the primary carbonate material. Some trace elements form substitutions in clay or carbonate minerals. Zn, Pb, Cu, Mo, and Ni may be associated with sulfides, and Ti and Cr may be associated with oxides. Sc and REY usually substitute Ca ions in calcite. The contents of measured Ce, Nd, Sm, Dy, Er, and Y vary from below 1 ppm up to 6 ppm, and Sc from 0 ppm to 10 ppm.

Synthesis of mullite by high temperature reaction to realize nontoxic and efficient recycling of vanadium slag chlorination residue

The compositions of the leaching residue obtained by chlorination method to extract valuable elements (Ti, Cr, Fe, Mn and V) from vanadium slag were mainly Al2O3 and SiO2 with a small amount of hazardous elements Cr and V. In order to reduce the pollution of V and Cr to the environment, a novel method for nontoxic and efficient recycling of leaching residue was proposed. Mullite with high compressive strength of 133.345 MPa and bulk density of 3.20 g/cm3 was successfully synthesized by using leaching residue as raw material, adding appropriate SiO2 and roasting at 1600 °C for 5 h. The trace element Ti and hazardous elements V and Cr in leaching residue entered the mullite lattice in the high temperature reaction process to form a solid solution, which were stabilized in the mullite phase. The synthesized samples were tested by toxicity characteristic leaching procedure (TCLP) and GB5085.3—2007. The results showed that mullite met the toxic leaching standard and was a nontoxic product.

Luminescence Characteristics of Green Grossular Garnets

Some light green grossular garnets exhibit orange-red luminescence under long-wave and short-wave ultraviolet light. To characterize their luminescence behavior, we studied seven grossular garnets with typical colors ranging from light yellowish-green to intense green by using photoluminescence (PL), ultraviolet–visible (UV–Vis) spectroscopy, electron paramagnetic resonance (EPR), Electron Probe Microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). In the PL spectra of these grossular garnets samples, a broad band exists at about 589 nm and three sharp peaks appear at 697, 702 and 716 nm. The three-dimensional fluorescence spectra reveal two luminescence emissions. They are (1) a broad band near 600 nm; and (2) a series of sharp peaks centered at 697, 702 and 716 nm. In the UV–Vis spectra, two prominent asymmetrical absorption bands near 430 and 605 nm are related to Cr3+ or Cr3+/V3+, and minor absorption peaks at 408 and 419/420 nm are related to Mn2+. EMPA and LA-ICP-MS analysis confirmed the existence of trace elements Ti, V, Cr and Mn. Furthermore, the EPR spectrum excluded the existence of V2+ and V4+ and confirmed the existence of Mn2+, Cr3+ and Fe3+. Regarding V, an interesting phenomenon was reported in which the intensity of luminescence could be suppressed in grossular garnets with higher concentrations of V. These results imply that chromium and manganese are the luminescence activators in grossular garnets, and vanadium is a powerful quencher.

Systematic textural and geochemical variations in magnetite from a porphyry-skarn Cu (Au) system and implications for ore formation, perspective from Xinqiao Cu-Fe-Au deposit, eastern China

Magnetite is an abundant mineral in both porphyry ore and related skarn ore; the physical and chemical characteristics of magnetite in different parts of mineralized zones may allow determination of the related ore-forming processes. We present the results of detailed textural and chemical studies of magnetite from Xinqiao porphyry-skarn Cu-Au deposit, eastern China, to constrain the causative magmatic-hydrothermal processes.Five types of magnetite are identified, magmatic magnetite (type1) occurs in the causative quartz monzodiorite intrusion; re-equilibrated magmatic magnetite (type2) occurs in endoskarn; hydrothermal magnetite aggregated with hydrothermal biotite (type3a) or disseminated (type3b) and veins (type3c) occurs in the porphyry alteration zone; massive magnetite (type4) and disseminated or banded magnetite (type5) occurs in the exoskarn. Magmatic magnetite with oxy-exsolution of ilmenite lamellae indicates the magma was oxidized, and type1 magnetite that underwent hydrothermal re-equilibration (replaced by titanite and hematite) to form type2 magnetite indicates that the early magmatic-hydrothermal fluid was high temperature and highly oxidized during endoskarn formation. The Ti-rich type3a-c magnetite and the presence of ilmenite-rutile lamellae in type3c magnetite from the porphyry alteration zone demonstrate Ti mobility in the porphyry ore-forming fluid, which was high T (450 °C), oxidized and volatile-rich (hydrothermal fluorapatite; F > 3.0 wt%). Trace elements Ti, V, Sc, Co, Ni are positively correlated and decrease from type3 to type5; Mg, Mn, Zn increase in the same sequence, consistent with the temperature of fluid decreasing from porphyry to skarn mineralization, and increasing fluid-rock interaction. The elevated Sn in type5 magnetite and its coexistence with hematite in the retrograde skarn zone also indicate that the fluid remained oxidized during early skarn ore formation. Crystallization of magnetite increased the supply of reduced sulfur, which assisted formation of the Cu mineralization at Xinqiao. We highlight that magnetite textures and compositions can effectively trace the ore-forming processes in porphyry-skarn deposits, and show that porphyry related skarn magnetites are distinguishable from those in skarn Fe, skarn Cu, IOA (iron oxide-apatite) and porphyry deposits in the MLYB.

New insights into particle-bound trace elements in surface snow, Eastern Tien Shan, China

Trace elements (TEs) in the insoluble particles of surface snow are less affected by melting processes and can be used as environmental proxies to reveal natural and anthropogenic emissions. Here the first comprehensive study of the 16 TEs (Al, As, Ba, Bi, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Sr, Ti, U, V, and Zn) in insoluble particles (>0.45 μm) from surface snow samples collected at Urumqi Glacier No. 1 (UG1), Eastern Tien Shan, China, from February 2008 to January 2010 were presented. Results show that concentrations of most insoluble particulate TEs (TEs insol) in the snow were higher in summer while lower in winter, due to the increasing particle inputs and melting processes. The abundances of As, Cr, Cu, Ni, Pb, and Zn in some samples were higher than those in surrounding urban soils, which might due to these TEs have further anthropogenic input beyond the already contaminated re-suspended urban soil particles and TEs were mainly enriched in particles with small grain size. Based on enrichment factor (EF) and principal component analysis (PCA), our results suggest that eight TEs (Al, Fe, Ti, Ba, Mn, Sr, U, and V) mainly came from mineral dust, while the remaining eight TEs (As, Bi, Cr, Cu, Ni, Pb, Sn, and Zn) were affected by coal combustion, mining and smelting of non-ferrous metals, traffic emissions, and the steel industry. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests that pollutants might originate from Xinjiang province, Kazakhstan, and Kyrgyzstan. Moreover, UG1 received more significant inputs of particle-bound pollutants in summer than in winter due to the stronger convection and the prevailing valley wind that transports pollutants from the city of Urumqi.

Effect of Trace Element on Microstructure and Fracture Toughness of Weld Metal

The microstructure and fracture toughness of weld metal under Ti-free and Ti-containing different fluxes were investigated in this study. It was found that the trace element Ti of flux in submerged arc welding produced significant influence on the fracture toughness. The addition of 60 ppm Ti induced the sharp increase in J0.2 value from 232.78 to 364.08 kJ/m2. Microstructure characterization revealed that a large number of oxide inclusions prompted the nucleation of acicular ferrites and refined grains, which improved the fracture toughness of Ti-containing weld metal greatly. Moreover, the crack propagation path was more tortuous and bifurcated due to the small amount of carbide precipitations along grain boundaries and blocky martensite–austenite islands for Ti-containing weld metal. Meanwhile, the large-angle grain boundaries caused crack deflection and increased the resistance of crack propagation compared to Ti-free weld metal.

Groundwater risk assessment investigations for oil shale exploitation in El-Lajjun area of central Jordan

Oil shales are sedimentary rocks that contain organic material in its inorganic matrix. The oil shale deposits of Jordan have been investigated since the 1960s. An extensive investigation studies have been commenced to evaluate the quality and quantity of these resources. In 2006, the government of Jordan invited pioneer companies in oil shale field to submit their proposal to utilize and develop the oil shale of Jordan using different extraction technologies. Jordan is considered one of the driest countries in the world, which poses an additional challenge for oil shale development, because a vast quantity of water is needed for this process. El-Lajjun study area is located in central Jordan; the oil shale in the study area was deposited in marine environment; it comprises massive beds of brown-black, kerogen-rich, bituminous chalky marl. Ten representative oil shale rock samples were collected for risk assessment investigations from different localities of oil shale exposures. A standardized laboratory Fischer assay test delivered oil shale characteristics. Sequential extraction was used to evaluate mobility and distribution of the trace elements Ti, V, Cr, Co, Zn, As, Zr, Cd, Pb, and U. Column leaching experiments were performed to simulate the leaching behavior of the above elements from oil shale and spent shale to evaluate the possible negative impact on groundwater in the study area. Results of sequential extraction indicate that concentration of trace elements and trace elements are richer in oil shale and in the spent shale compared to most rocks and soils. The concentrations in the leachate were below the maximum contaminant levels of the Environmental Protection Agency (EPA) and the Jordanian standards for drinking water. The significance of this study lies in that its utilizes for the first time the sequential extraction and column leaching techniques to investigate the Jordanian oil shale rocks.

Biomonitoring environmental status in semi-enclosed coastal ecosystems using Zostera noltei meadows

Semi enclosed waters, such as estuaries and lagoons, are vulnerable ecosystems that are experiencing persistent trace element (TE) contamination. Seagrasses have been reported worldwide as valuable bioindicator species for coastal contamination monitoring purpose. This is, to our knowledge, the first time the TE contamination of semi-enclosed ecosystems has been monitored along the full latitudinal gradient of the Moroccan Atlantic coast. In these ecosystems, the dominant seagrass species is Zostera noltei. 23 TEs (Fe, Al, Cr, Mn, Co, Ni, V, Cu, Zn, Sr, Li, As, Ag, Cd, Sn, Sb, Mo, Ba, Ti, Pb, U, Bi and Hg) and four major elements (Na, Mg, K, Ca) were measured in sediments and seagrass leaf samples were collected upstream and downstream of five semi-enclosed areas. They contrasted in both climatic conditions and levels of environmental contamination. The Trace Element Pollution Index (TEPI) and the Trace Element Spatial Variation Index (TESVI) were calculated from chemical element concentrations in the samples. Of the five semi-enclosed areas, Sidi Moussa lagoon’s sediments were the most contaminated (TEPI = 1.18). The TESVI differed highly between chemical elements among the five water bodies for sediments and seagrass leaves, the highest spatial variability being for Ag (TESVI = 72.01 and 21.05 respectively). For Z. noltei leaves, a latitudinal gradient of TE accumulation was recorded. A high bioconcentration factor (BCF > 1) for Cd, Mo, Sb, Ag, Zn and U indicated that the sediments were efficiently uptaken by the seagrass. Significant correlations (p < 0.05) between levels of Cd, Ag, Fe, Al, Ba, Hg, Mn and Zn in sediments and in Z. noltei leaves indicated similar contamination occurrences in both environmental matrices and their bioavailability for seagrasses. Overall, leaf TE bioconcentration among and within the study sites resulted from differences in element bioavailability and environmental conditions (climatic context, hydrological conditions and human impact). Ultimately, Z. noltei is a useful bioindicator of Cd, Mo, Sb, Ag, Zn, U, Al, Fe, Mn, Ba and Hg contamination in sediments.

Conversion of multi-layered Mg-based carrier to hydrogen storage performance

The mixed powder method and covering method were adopted to prepare a composite that has hydrogen storage properties. In the experimental process, the alloy phases Mg2Ni and NiTi generated regularly; the penetration of the hydrogen atoms to the material was considered as the adsorption of the material to the hydrogen atoms; the original thermodynamic equation was edited; the crystal phases were optimized by adjusting the parameters about the material composition and gas concentration, so that providing advantageous channels of the hydrogen atoms in and out to improve the hydrogen storage properties. The results showed that integer multiples adjustment to trace element Ti could make hydrogen storage properties maximizing optimize and have controllability for the capacity and rate of hydrogen storage according to the newly editing equation. The innovation was to edit out equation that can improve the hydrogen storage properties through adjusting three parameters of trace element Ti, adsorption and penetration to find the most optimal condition improving the hydrogen storage properties.

Influence of W, Mo and Ti trace elements on the phase separation in Al8Co17Cr17Cu8Fe17Ni33 based high entropy alloy

Compositionally complex alloys, also called high entropy alloys, have been investigated for over a decade in view of different applications, but so far only a small number of alloys can be considered as presenting good enough properties for industrial application. The most common family of elements is Al–Co–Cr–Cu–Fe–Ni. The equiatomic alloy having 5 phases and being too brittle, the composition has been modified in order to improve the mechanical properties. Different compositions have been tested and as a first result ductile Al8Co17Cr17Cu8Fe17Ni33 has been chosen for deeper investigation. It shows a dendritic segregation into Co–Cr–Fe rich cores and Al–Cu–Ni rich interdendritic sites. The as-cast state is characterized mainly by two phases, namely Al–Cu–Ni rich precipitates of L12 structure inside a solid solution matrix. After homogenization both alloys consists of a single solid solution phase. Results are compared to calculations by ThermoCalc. In order to further improve the properties of the alloy the Cr content has been decreased and replaced by trace elements W, Mo and Ti, which, according to ThermoCalc, increase the melting point and the phase transition temperature which leads to the formation of the L12 phase. As-cast and heat treated samples of the base and the modified alloy have been investigated by transmission electron microscopy and three dimensional atom probe. Results of the investigations will be discussed in terms of microstructure, hardness and coherence with Thermo Calc predictions.

Determination of Ti, Zr, Nb, V, W and Mo in seawater by a new online-preconcentration method and subsequent ICP–MS analysis

We present a new method for the determination of Ti, Zr, Nb, V, W and Mo in seawater by adapting the online-preconcentration procedure with the system SeaFAST and subsequent analysis by ICP–MS to these metals. The trace elements Ti, Zr, Nb and W are present in seawater in ultratrace concentrations in the range of pmolkg−1, whereas Mo and V, which are biologically essential elements, are present in the concentration range of nmolkg−1. The online-preconcentration system we used consists of an autosampler, a sample loop, a preconcentration column and two valves controlling the sample loop and the preconcentration processes. The pre-packed preconcentration column contains a chelating resin with two functional groups, ethylenediamine triacetic acid (EDTriA) and iminodiacetic acid (IDA), immobilized on a polymer backbone. The preconcentration process was optimized for loading the sample and subsequent rinsing to remove residues of seawater matrix prior to elution with the optimized elution acid (0.5M HNO3–0.002M HF). We used acidified North Sea seawater (0.02M HCl–0.002M HF) for the method development. Samples and calibration standards were loaded onto the preconcentration column and after elution directly transferred to the quadrupole ICP–MS and measured immediately. Best results were achieved with matrix-matched calibration standards (0.6M NaCl–0.02M HCl–0.002M HF) simulating acidified seawater samples. Titanium, Zr, Nb and W are measured simultaneously in one run, whereas V and Mo are determined simultaneously in a separate run. Low procedure blanks were calculated for Ti, Zr, Nb, W (635, 14.5, 1.35, 10.2pmolkg−1) and for V and Mo, 9.79 and 5.61nmolkg−1, respectively. Very good spike recoveries achieved with spiked North Sea water demonstrate the applicability for all six elements. Analysis of the seawater standard NASS-6 gave recoveries of 97–99% (0.9–2.2% standard deviation, SD) for Mo and V. We also provide Zr, Nb and W data for this reference standard. The applicability of the on-line preconcentration method was demonstrated for samples collected during a GEOTRACES cruise in the Atlantic. Due to the low limit of quantification, LOQ, and SD, this method enables the determination of ultratrace concentration levels for Ti, Zr, Nb and W as well as the detection of small variations in concentration for all six elements. The required sample volume of only 50mL, the fast determination within 1h for all elements and the principle of a closed system are a clear advantage of the analytical procedure compared to many other methods and facilitates sample logistics for the determination of Ti, Zr, Nb, V, W and Mo in seawater.

Phosphorus zoning reveals dendritic architecture of olivine

Quantitative spot analyses were acquired with the JEOL JXA-8500F field-emission gun electron probe micro-analyzer of the University of Hawaii – Manoa over two sessions. Olivine was analyzed during the first session with an electron beam tuned at 20 keV, 50 nA and 10 µm probe diameter. The elements were acquired using five analyzing crystals as followed: one LiFH for Cr and Ni, one LiF for Fe and Mn, one PETJ for Ca and Ti, one PETH for P, and two TAPJ crystals for Al, Si and Mg. The standards used were Verma garnet for Mn, San Carlos olivine USNM 111312/444 for Fe, Si, Mg and Ni, sphene glass for Ti, chromite USNM 117075 for Al and Cr, and fluor-apatite USNM 104021 for Ca and P. The on-peak and off-peak counting times were each 20 s for Si, Al and Mg, 30 s for Mn, Ti and Ni, 35 s for Fe, Ca and Cr, and 70 s for P. The off-peak correction method was linear for major elements and exponential for trace elements Ti, Al, Cr and P, using Probe for EPMA software. Detection limits are in the range 0.005 – 0.01 wt%. Precision and accuracy (1) are 0.4 – 2 % for major elements (reported in weight percent oxide), 3 – 5 % for minor elements (Ca, Mn and Ni – reported in µg/g) and 20 – 70 % for trace elements (Al, P, Ti, and Cr – reported in µg/g in Table DR1), based on repeated analyses of San Carlos olivine standard (USNM 111312/444). Matrix glasses and melt inclusions were analysed during the second session with a beam tuned at 15 keV, 15 nA and 10 µm probe diameter. Elements were acquired using one LiFH for Ti and Cr, one LiF for Fe and Mn, one PETH for Ca and K, and two TAPJ crystals for Mg, Al, Na and Si (Na measured first). The standards were Verma garnet for Mn, Kakanui augite USNM 122142 for Al, Fe, Si, Mg and Ca, sphene glass for Ti, chromite USNM 117075 for Cr, Amelia albite for Na, and orthoclase OR-1 for K. The on-peak and off-peak counting times were 30 s for all elements. Detection limits for Cr2O3 and S are 0.02 wt%. Precision is better than 1% for all elements (1), except Na and K (<3%). Accuracy (1) is better than 5 % for all elements.

Studies on changes in trace elemental content of serum of uterine cervix cancer patients using PIXE

The objective of this study was to evaluate the levels of trace elements in blood sera of uterine cervix cancer patients, analyze their alteration with respect to healthy controls and identify the best predictors amongst these for disease occurrence and progression. Particle induced X-ray emission (PIXE) technique was used in this work to identify and quantify trace elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br in the blood sera of uterine cervix cancer subjects and healthy control subjects. The observed alterations are discussed with respect to the possible mechanisms by which these elements might influence the carcinogenic process.

Geochemical discrimination of the Upper Ordovician Kinnekulle Bentonite in the Billegrav-2 drill core section, Bornholm, Denmark; pp. 264–270

The content of the trace elements Ti, Nb, Zr and Th has been analysed in 34 Upper Ordovician bentonites from the Billegrav-2 drill core, Bornholm, Denmark. The section contains two 80–90 cm thick bentonites, which potentially may represent the Kinnekulle Bentonite, as well as several rather thick but composite bentonite layers with thin terrigenous shale interbeds. Comparison of the four immobile trace elements with data from the Kinnekulle Bentonite reported from other locations in Baltoscandia indicate that the 80 cm thick bentonite between 88.30 and 89.10 m in the Billegrav-2 core represents this marker bed. The other thick (90 cm) bentonite in the Billegrav-2 core, exceeding the thickness of the Kinnekulle Bentonite, belongs to the Sinsen or uppermost Grefsen Series bentonites. Bentonites in the Grefsen Series frequently contain much higher concentrations of trace elements than the Kinnekulle Bentonite.

Geochemistry of island arc dolerites and diorites along Qift–Quseir asphaltic road, central Eastern Desert, Egypt

The Precambrian basement rocks exposed along Qift–Quseir asphaltic road, central Eastern Desert of Egypt, exhibit two contrasted tectonic units, each of which has its own lithology structural style and grade of metamorphism. They are intruded by dolerite and diorite dykes. The alkali (Na2O+K2O) and TiO2 contents increase whereas Al2O3, FeO, MgO, CaO and MnO decrease with increasing SiO2 from dolerites to diorites. The trace elements Ti, Zr, Cr, Y and Ni indicate that the dolerites are tholeiitic with slight tendency toward calc-alkaline and formed from basaltic magma in an active continental margin, while diorites are calc-alkaline and were formed by fractional crystallisation of high-alumina basaltic magma in an island arc and active continental margin tectonic environment where they probably represent the forerunner of G1 granites. The molecular ratios Mg values (MgO×100/MgO+FeO) of dolerites range from 47 to 49 while those of diorite range from 51 to 59, indicating that the dolerite and diorite have suffered mild fractionation. Mineral chemistry for the diorites shows that the amphiboles are classified as magnesiohornblende and the plagioclase composition is An39–42 (i.e. the narrow range indicate that the pluton has not suffered extensive fractional crystallisation). The Al content of amphibole displays significant variation with pressure and temperature, also the change of the Ca/(Ca+Na) ratio of plagioclase is dependent on temperature. The amphibole–plagioclase geothermobarometer suggested the P-T formation conditions of studied dykes as 2 kbar and 600 °C.

Pyrite–anhydrite–magnetite–pyroxene-type deposits and coexisting hydrothermal fluids in Mesozoic volcanic basins, Yangtze River Valley, China

Anhydrite–pyrite–magnetite–pyroxene–type deposits occur in the Mesozoic volcanic areas of the Middle–Lower Yangtze Valley in China. These deposits are hosted in alkaline basaltic rocks, and are generally accompanied by melanocratic and leucocratic alteration zones, both of which are characterized by a distinct vertical zonation pattern. Investigation of these zones indicates that the chemical compositions of solid solutions and polymorphs of various minerals vary spatially in the alteration profile, upwards from the lowest level, and outwards from the center. Here we report a case study on the Luohe deposit. In the melanocratic-alteration zone, the composition of magnetite (including trace elements Ti, V, Mg, Mn), pyroxene (Mg, Fe 2+, Fe 3+, Al 2O 3), plagioclase (An x Ab 1 − x ), pyrite (Co, Ni) and apatite (F, CeO 2 + Y 2O 3 + La 2O 3) changes with depth. The isotherms of hydrothermal fluids determined from fluid inclusion data, including homogenization temperature and salinity, also vary with depth. Activity diagrams were constructed from mineral and isotherm analysis to estimate the chemical constraints on the alteration-mineral assemblages and the coexisting hydrothermal solutions for the Na 2O–K 2O–CaO–MgO–FeO–Fe 2O 3–A1 2O 3–SiO 2–H 2SO 4–H 2S–HCI–H 2O system at 350 to 600 °C and 500 bars (50 MPa), assuming that the major alteration mineral assemblages along the profile reflect the nature of the coexisting hydrothermal solutions. The activity diagrams adopted the major minerals as buffers to fix the activities of the aqueous species in the system, simulating the physicochemical conditions of the magnetite–anhydrite–pyroxene equilibrium and of solid solutions of diopside–hedenbergite, grossular–andradite and anorthite–albite found in the profile. This study provides an approach to modeling the chemical constraints of coexisting fluids in ore-alteration zones based on field observations.

Holocene and late glacial palaeoceanography and palaeolimnology of the Black Sea: Changing sediment provenance and basin hydrography over the past 20,000 years

The elemental geochemistry of Late Pleistocene and Holocene sediments of the Black Sea, recovered in box cores from the basin margins and a 5-m gravity core from the central abyssal region of the basin, identifies two terrigenous sediment sources over the last 20 kyrs. One source region includes Anatolia and the southern Caucasus; the second region is the area drained by rivers entering the Black Sea from Eastern Europe. Alkali metal:Al and heavy:light rare-earth element ratios reveal that the relative contribution of the two sources shifted abruptly every few thousand years during the late glacial and early Holocene lacustrine phase of the basin. The shifts in source were coeval with changes in the lake level as determined from the distribution of quartz and the heavy mineral-hosted trace elements Ti and Zr. The geochemistry of the abyssal sediments further recorded a sequence of changes to the geochemistry of the water column following the lacustrine phase, when high salinity Mediterranean water entered the basin beginning 9.3 kyrs BP. Bottom water that had been oxic throughout the lake phase became anoxic at approximately 8.4 kyrs BP, as recorded by the accumulation from the water column of several redox-sensitive trace metals (Mo, Re, U). The accumulation of organic carbon and several trace nutrients (Cd, Cu, Ni, Zn) increased sharply ca. 0.4 kyrs later, at 8.0 kyrs BP, reflecting an increase of primary productivity. Its increase was coeval with a shift in the dinoflagellate ecology from stenohaline to euryhaline assemblages. During this profound environmental change from the lacustrine to the marine phase, the accumulation rate of the lithogenous sediment fraction decreased as much as 10-fold in response to the rise of the water level in the basin from a low stand ca. 9.3 ka to its current level.

Eolian Additions to Late Quaternary Alpine Soils, Indian Peaks Wilderness Area, Colorado Front Range

Surface horizons of many alpine soils on Quaternary deposits in high-mountain settings are enriched in silt. The origin of these particles has been debated, particularly in the Rocky Mountain region of North America. The most common explanations are frost shattering of coarser particles and eolian additions from distant sources. We studied soil A horizons on alpine moraines of late-glacial (Satanta Peak) age in the Colorado Front Range. Surface horizons of soils on these moraines are enriched in silt and have a particle size distribution that resembles loess and dust deposits found elsewhere. The compositions of sand and silt fractions of the soils were compared to possible local source rocks, using immobile trace elements Ti, Nb, Zr, Ce, and Y. The sand fractions of soils have a wide range of trace element ratios, similar to the range of values in the local biotite gneiss bedrock. In contrast, silt fractions have narrower ranges of trace element ratios that do not overlap the range of these ratios in biotite gneiss. The particle size and geochemical results support an interpretation that silts in these soils are derived from airborne dust. Eolian silts were most likely derived from distant sources, such as the semiarid North Park and Middle Park basins to the west. We hypothesize that much of the eolian influx to soils of the Front Range occurred during an early to mid-Holocene warm period, when sediment availability in semiarid source basins was at a maximum.

Fingerprinting the water site in mantle olivine

Research Article| November 01, 2005 Fingerprinting the water site in mantle olivine Andrew J. Berry; Andrew J. Berry 1Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Search for other works by this author on: GSW Google Scholar Jörg Hermann; Jörg Hermann 1Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Search for other works by this author on: GSW Google Scholar Hugh S.C. O'Neill; Hugh S.C. O'Neill 1Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Search for other works by this author on: GSW Google Scholar Garry J. Foran Garry J. Foran 2Australian Synchrotron Research Program, Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW 2234, Australia, and Australian National Beamline Facility, KEK, Photon Factory, Oho 1-1, Tsukuba-shi, Ibaraki-ken 305-0801, Japan Search for other works by this author on: GSW Google Scholar Geology (2005) 33 (11): 869–872. https://doi.org/10.1130/G21759.1 Article history received: 12 Apr 2005 rev-recd: 03 Jun 2005 accepted: 06 Jul 2005 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Andrew J. Berry, Jörg Hermann, Hugh S.C. O'Neill, Garry J. Foran; Fingerprinting the water site in mantle olivine. Geology 2005;; 33 (11): 869–872. doi: https://doi.org/10.1130/G21759.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Nominally anhydrous minerals such as olivine contain trace amounts of water and may accommodate the entire water budget of the upper mantle. Here we report for the first time synthetic olivines, crystallized experimentally under upper mantle conditions, that reproduce the most common and intense infrared hydroxyl stretching bands (at 3572 and 3525 cm−1) observed in spinel peridotite mantle olivines. These bands arise from water accommodated at point defects associated with the trace element Ti, and we suggest that this is the most important defect site in the shallow upper mantle. Additional hydrated defects may occur at higher pressures. We also identify bands related to water associated with Fe3+; these are unlikely to reflect equilibrium with the mantle, and indicate water incorporation during exhumation or retrogression. Water must be present at the defect site appropriate for the mantle, at the conditions of interest, for partitioning, seismic wave speed, and deformation experiments on hydrous olivine to be relevant. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Chromite in Komatiites, 1. Magmatic Controls on Crystallization and Composition

Chromite is a widespread accessory mineral in komatiites, ranging Zhou & Kerrich, 1992). This is the first in a series of papers which addresses the occurrence of chromite in from skeletal through euhedral and equant to lobate and rarely poikilitic habits depending on cooling regime and the composition komatiites and its chemical variability. This paper looks at the factors controlling the crystallization of chromite of the coexisting olivine. Chromite is least abundant in highly magnesian chrome-undersaturated lavas, and most abundant in from komatiites, and at the textural and compositional variation within chromites which have apparently restrongly differentiated layered cumulate bodies. Abundances are typically lower than the expected cotectic proportions. Chromite tained some or all of their igneous characteristics. Textural and compositional features of chromites are compositions reflect variations in lava composition and oxygen fugacity; reaction with trapped intercumulus liquid; and sub-solidus interrelated in complex and interesting ways, and show systematic relationships to host rock chemistry and crysFe–Mg exchange with olivine. Primary chromites in thick dunitic channels and sheet flows have very low Fe contents, whereas tallization regime. Future papers in the series will deal with superimposed metamorphic effects. comparable thin flow chromites contain higher Fe. This is attributed to an initial reduced state of the magma, thin flow lavas A large body of new data on chromite compositions, including high-precision wavelength-dispersive analyses being subsequently oxidized because of post-eruption processes. Extensive reaction of chromite with trapped liquid causes decreasing of minor and trace elements Ti, V, Mn, Zn, Ni and Co, is presented from the Norseman–Wiluna Greenstone Belt Mg/(Mg+ Fe), and enrichment in Fe, TiO2, V2O5, MnO, CoO and ZnO. Nickel trends depend on sulphide content. These in Western Australia, and synthesized with a compilation of literature data taken mainly from Roeder (1994) and trends are best developed in rocks combining presence of trapped intercumulus liquid with prolonged cooling histories. The deficiency various unpublished sources. Whole-rock geochemical data are similarly compiled from the literature and some of chromite in channelized environments is partly a consequence of more primitive lavas being found in these environments, but is unpublished sources, and include a large body of data collected over the last 15 years at CSIRO. Details of mainly due to the difficulty in nucleating chromite crystals under low degrees of supercooling. data sources are listed in Appendix A, and details of electron microprobe analytical techniques in Appendix B.