Concentration Of Certain Elements Research Articles

Precise Moessbauer milliprobe determination of ferric iron in rock-forming minerals and limitations of electron microprobe analysis

For estimations of P - T conditions of igneous and metamorphic rocks, Fe 3+ in coexisting minerals is either assumed to be zero or is calculated from electron microprobe analyses (EMPA) based upon stoichiometry and charge balance. Geothermobarometers that involve Fe 2+ - Mg 2+ exchange can be significantly affected by either neglecting Fe 3+ or using incorrect values. Ratios of Fe 3+ /ΣFe in garnet and clinopyroxene measured by a Mössbauer milliprobe were compared to those calculated from EMPA of garnet and clinopyroxene from eclogite xenoliths from the Udachnaya kimberlite in Yakutia. The effects of Fe 3+ contents in garnet and clinopyroxene on temperature estimations were evaluated. The following Fe 3+ /ΣFe (in at%) values were obtained (EMPA/Mössbauer): Gt = 9.4/6.0; 11.5/7.0; 19.4/16.0; and 24.7/15.0; Cpx = 22.0/22.9; 34.2/22.0. The effects of Fe 3+ in clinopyroxenes on calculated temperatures are illustrated by taking eclogitic clinopyroxene compositions and changing contents of certain elements within the range of standard deviations for EMPA of those particular elements. Increasing Na 2 O contents from 5.67 to 5.74 wt% (< 2.0% relative error) would lead to increasing Fe 3+ /ΣFe from 31.6 to 47.1%, thereby decreasing the calculated temperature from 1026 to 941 °C. Various Fe 3+ /ΣFe values for garnet and clinopyroxene were also tested for their effects on calculated temperatures: for clinopyroxene, T decreases with increasing Fe 3+ /ΣFe whereas for garnet, T increases with increasing Fe 3+ /ΣFe. This compensation effect between garnet and clinopyroxene moderates the variation in temperature estimations of eclogites based on Fe 3+ corrected vs. uncorrected microprobe analyses. Little correlation exists between EMPA-calculated and Mössbauer-measured Fe 3+ /ΣFe values for these mantle-derived garnets and clinopyroxenes. Even a small relative error in Fe 3+ may significantly change calculated temperatures of equilibration, seriously affecting petrologic interpretations. In particular, uncertainty in Fe 3+ calculated from EMPA of silicate minerals leads to serious questions with regard to K D values obtained from natural assemblages.

Isotope-Geochemical and Mineralogical-Petrographic Characteristics of the Pergamon Altar Marble

We report preliminary results of our provenance study of marble from the Telephos Frieze of the Pergamon altar. The emphasis here is on the stable isotope geochemistry of marble. The obtained δ13C values (2.4 to 3.5‰) vary insignificantly. However, the δ18O values give two clusters. The isotopically light marbles (close to −9.5‰) derive from panels 1–8 and the heavy marbles (−3.5 to −1.0‰) derive from panels 11–50. Mineralogical, petrographic and geochemical investigations (accessory minerals, grain size distribution, rare earth elements) further refined the marble characteristics. In spite of certain differences observed (grain size distributions, isotopy and contents of certain elements) for the two marble groups, the present data support a common provenance. So far, east Aegean islands and the Marmara region are favored.

Electron spectroscopic imaging: detection and resolution limits, quantitative evaluation

One of the main applications of the new imaging energy filters is to obtain elemental distribution images by electron spectroscopic imaging (ESI). Before the technique can successfully be applied to new materials problems it is important to evaluate the detection and resolution limits which have to be expected. Since the intensities in ESI images recorded with inner shell loss electrons are very small, the detection limit is governed by the signal to noise ratio (S/N). In a systematic study we have evaluated the performance of three different electron microscopes, a Zeiss EM 912 Omega, a Philips CM 20, and a Jeol ARM 1250, the latter two being equipped with a Gatan imaging filter (GIF). As experimental systems we chose amorphous oxide grain boundary films in Si3N4 ceramics and thin diamond films on silicon substrates. Furthermore, new routines were developed to extract EELS spectra from a whole series of ESI images. These EELS spectra can be used to study the local variation of the near edge fine structure (ELNES) or, after quantitative evaluation, of the chemical concentration of certain elements.

Analysis of zinc and other elements in rat pancreas, with studies in acute pancreatitis.

Determination of the concentration of certain elements makes it possible to investigate the physiology of the pancreas. We used X-ray fluorescence to determine the concentrations of zinc and other elements in the pancreas of normal (control) rats and those with cerulein-induced pancreatitis. Ten elements (Zn, Ni, Fe, P, Ca, Cl, S, K, Ti, and Mn) were detected in controls. In the early stage of acute pancreatitis, the pancreatic concentrations of Zn, Ni, Fe, and P were significantly decreased (P < 0.05) and those of Ca and Cl were significantly increased (P < 0.05), compared with control levels. However, levels of S, K, and Ti did not differ significantly from the control values. Mn was detected in only some samples. The serum levels of Zn and Fe were significantly elevated (P < 0.05) in acute pancreatitis. These observations indicate that Zn and these other nine elements could play an important role in acute pancreatitis.

Determining distribution and concentration of certain elements with the aid of a charged-particle beam

Determining distribution and concentration of certain elements with the aid of a charged-particle beam

Changes in Concentration of Certain Elements During Maturation of Muscadine Grapes (Vitis rotundifolia)

ABSTRACTChanges in percent ash and certain elements were followed during maturation of berries of two cultivars of muscadine grapes (Vitis rotundifolia). Analyses were done on deseeded berries. Percent ash increased significantly during maturation of Carlos berries, but did not increase significantly during maturation of Noble berries. Potassium was the element in highest concentration in both cultivars during maturation and at harvest. Potassium, calcium, phosphorus, and sodium were the major elements found to be significantly correlated with maturation and were found in concentrations similar to those reported in the literature for V. vinifera grapes. Iron, copper, zinc, and manganese were minor components. Four additional muscadine cultivars, sampled only at full maturity, had similar concentrations of elements to those found in ripe berries of Carlos and Noble. The averaged values of ash (%) and elements (ppm) for all six cultivars when sampled at their normal harvest dates are: ash = 0.57; Na = 58.6 (Carlos and Noble only); P = 99.6; K = 1641.0; Ca = 124.2; Mg = 59.2; Mn = 7.2; Cu = 0.5; Zn = 0.5; Fe = 3.0.

The colour of Pinus silvestris L. seeds and their susceptibility to damping‐off. II. Colour of seed coats and their chemical composition

AbstractBlack seed of Scots pine are more resistant to damping‐off. The content of certain elements and chemical compounds in the seed coats differs widely depending on seed colour and physiological state (resting, germinating and infected seeds). The quantitative and qualitative differences in fatty acids content, total nitrogen, amino acids, some metals and nonmetals, chlorogenic acid, phenol and a number of its derivatives seem to be some of the factors conditioning differences in resistance to damping‐off.

Diagenetic and postdiagenetic changes in the composition of an Archean pillow

An Archean basaltic pillow of greenschist metamorphic facies and a modern sea-floor pillow with minor diagenetic alteration are comparably zoned from rim to core as follows: a 'glassy' rim, a zone of incipient crystallization, and a crystalline interior, but the petrography of each is appropriate to its metamorphic stage. The Archean pillow varies markedly in composition inward, with the major changes taking place at the rim and at the margin of the crystalline interior; the centre is a broad zone of fairly uniform composition. Relative to the centre zone, alkalis and silica are greatly depleted and iron, lime, and magnesia greatly enriched at the rim, whereas the proportions are approximately reversed at the margin of the crystalline interior. The abundance and, in part, composition of metamorphic minerals reflect the same zoning: chlorite and epidote predominate at the rim, and feldspars concentrate at the margin of the crystalline interior. The bulk of the crystalline interior is a uniform intergrowth of actinolite–epidote–chlorite–albite–sphene–quartz–calcite. Epidote is iron–enriched and iron–depleted at the rim and the margin of the crystalline interior respectively. These variations can be attributed to a pre-existing diagenetic alteration analogous to that recognized in the modern pillow where palagonitization of the glassy rim is attended by oxidation of iron and a concentration of certain elements, notably alkalis, at the pillow margins. With metamorphism, epidote develops at the pillow rims because of oxidation induced by palagonitization and the residual glass is replaced by chlorite. Elements incompatible with these minerals migrate to the margin of the crystalline interior where they can be accommodated in the developing metamorphic assemblage. Little net change in the composition of the pillow is evident.

Variation in the Concentration of Certain Elements in Muscadine Grape Leaves Related to Season, Leaf Portion, and Age1

Abstract Chemical analysis of 3 portions (margin, midrib, and petiole) of immature and mature muscadine grape leaves (Vitis rotundifolia Michx. cv. Scuppernong) were carried out from samples collected at six 3-week intervals in 1971. The concentrations of N, Mn, Fe were higher in the leaf blade than in the petioles. Concentration of P, K, Ca, Mg, Cu, and Zn were higher in petioles than in the leaf blades. Difference in elemental concentration in the 2 portions of the leaf blade were evident only with K and Mn. The concentrations of Mg in the 2 portions of the blade were the same early in the season and decreased during the season, but the rate of decrease in the margin portion tended to be more rapid than in the midrib after the second sampling date. The decrease in Mg concentration in the blade coincides with the appearance of visual Mg deficiency symptoms. Seasonal variation was evident for all elements analyzed but slopes of the curves of the different leaf portions for a given element were often quite different. Data are presented for elemental concentration of 3 leaf portions of immature and mature leaves. In all cases, except B, elemental concentrations varied with leaf portions.

Possibility of migration of certain elements in biological systems during x-ray irradiation

The effect of local x-ray irradiation on the content of certain elements in cell components (nuclei, mitochondria) and blood serum of rats with transplanted sarcoma M-1 in a dose of 250 R during growth of the tumor was shown to lead to a redistribution of Zn from the nuclei into the mitochondria. Statistically significant postradiation changes also were found in the content of Ca, Mg, Cu, and Zn in the blood serum of rats with a transplanted sarcoma M-1 after a single session of local irradiation of the tumor in a dose of 1000 R.

Preferential concentration of certain elements in smaller aerosols emitted from aircraft engines

Aerosols from aircraft engines were collected with an Andersen eight-stage cascade sampler for a period of 24 h. The aerosol samples from each stage were analyzed for their elemental composition using the proton-induced x-ray emission (PIXE) technique. Seventeen elements (Si, P, S, Cl, K, Ca, Ti, V, Fe, Ni, Cu, Zn, Br, Sr, Nb, Sn, and Pb) were positively identified and quantitated at each stage. Six elements (S, Ca, Fe, Zn, Sn, and Pb) showed fractional concentration increase with the decreasing aerosol size. Similar, but less well-defined, trends were also observed for V and Ni. Silicon and chlorine, on the other hand, showed an opposite trend. Neutron activation analysis of bulk aerosol samples collected every 2 h over the same period showed correlation of concentration of Si, Ca, V, Ti, Zn, Br, and Sn with the density of air traffic at the airport. Analysis of the aviation fuel samples by PIXE indicates that major fractions of Pb, Sn, Br, Zn, Ni, Fe, V, Ca, and S observed in these aerosol studies come from the aircraft engine exhaust.

Trace-Element Analysis in Hair: An Evaluation

Abstract The use of hair as an index to the concentration of certain elements in tissues has been evaluated with regard to the effect of prior cosmetic and sample-washing treatments on the results. Untreated rat-hair samples were subjected to selected grooming or cosmetic products and then washed by various commonly cited sample-preparation procedures. The hair samples were then analyzed for Ca, Mg, Cu, and Zn, and the concentrations found were compared to those in untreated samples. The results indicate that the values observed can be greatly altered by typical treatments given to human hair, and that such changes are not corrected by the commonly used sample-wash procedures. Thus, obtainable samples of human hair, including pubic hair, cannot be expected to indicate accurately the concentration of these metals that would otherwise be present. Other elements should be similarly studied before confidence can be placed in the validity of data for them.

Determination of certain elements in human serum albumin by neutron activation analysis

Instrumental activation analysis was used to determine the contents of certain elements in human serum albumin (HSA). Sample irradiation was performed with a thermal neutron flux of 1.5·1013 n·cm−2·sec−1 in the RA nuclear reactor of the Boris Kidric Institute, Vinca. Measurements were performed on a 4096-channel analyser with a high-resolution Ge(Li) detector. The Na, Cu, Br, Au, Hg, Cr, Fe, Ag, Sc, Ba and Co contents were determined in HSA produced by the Institute for Blood Transfusion, Belgrade.

REQUIREMENTS FOR THE MAINTENANCE AND GROWTH OF APHANIZOMENON FLOS‐AQUAE IN CULTURE1,2

SUMMARY Aphanizomenon flos‐aquae has been introduced into unialgal culture in a completely defined medium and maintained for more than 3 years in the colonial flake form found in nature. The color and size of the flake and general appearance of the cells are substantially improved over those found in the original material at the time of collection from Upper Klamath Lake, Klamath County, Oregon. The alga readily forms both akinetes and heterocysts in culture Bacteria‐free cultures have not been obtained.A precipitate‐free medium designated ASM No. 8a has been developed from the ASM of McLachlan and Gorham. Their medium was altered by modifying the concentration of certain elements and by the addition of sodium bicarbonate, a 1/25 dilution of Arnon's trace element solutions B7 and C13, hydrogen ferric ethylenediamine di‐o‐hydroxyphenylacetate (EDDHA), and disodium ethylene dinitrilotetra‐acetate (Na2EDTA).

Bacterial activity in sediments of shallow marine bays

Complete mineralization of organic matter results from a multitude of complex bacterial activities which must involve more than one species of bacteria. The diverse bacterial activities influence the pH, redox potential, production of gases and their resulting disfiguration of the sediment, concentration of certain elements, precipitation and solution of carbonates, diagenesis of silicates, the production of complex organic compounds such as surface-active agents and many other properties of sediments. The bacterial activities are not constant but proportional to the amount of organic matter, pH, sediment particle size, temperature, sequence of physical changes caused by the bacteria in the sediment and the sequence of the production of organic by-products during decomposition.

On the concentration of certain elements at the earth's surface

A survey of the abundances of elements in the ocean and sedimentary rocks as compared to their abundances in the weathered igneous rocks shows that carbon, nitrogen, oxygen as water, chlorine, bromine and boron are highly concentrated in the surface materials and that thicknesses of from 17 to 89 km of the outer part of the earth would be required to produce these elements if all of them now present in the igneous rocks were removed. A study of the available information indicates that many other elements would be concentrated at the earth’s surface if chlorine, bromine and boron were concentrated there by a high-temperature volatilization process either from volcanoes or in an original high-temperature atmosphere of the earth . It is concluded that the removal of these elements from the outer parts of the earth occurred through solution in water at low or moderate temperatures ( ~ 100°C or less), since they are soluble and other elements are not. Iodine should belong to this group, but its position is uncertain because of doubtful analytical data. Sulphur may belong in some degree with the volatiles, i.e. carbon as methane or carbon dioxide, nitrogen as ammonia or molecular nitrogen, and water. It is shown that the low abundances of mercury and arsenic in the sediments are inconsistent with a temperature of formation of the earth’s surface regions higher than a few hundred degrees centigrade. The presence of appreciable quantities of nitrogen in the igneous rocks indicates that this element was present in condensed phases during the earth ’s formation, and a survey of the conditions of stability of such compounds indicates temperatures of about 200°C or less. It has not been possible to decide whether liquid water was present on the primitive earth .

Spectroscopic distribution of minor elements in igneous rocks from Jamestown, Colorado

Research Article| May 01, 1942 Spectroscopic distribution of minor elements in igneous rocks from Jamestown, Colorado JOSEPH M. BRAY JOSEPH M. BRAY Search for other works by this author on: GSW Google Scholar GSA Bulletin (1942) 53 (5): 765–814. https://doi.org/10.1130/GSAB-53-765 Article history received: 30 Jan 1941 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation JOSEPH M. BRAY; Spectroscopic distribution of minor elements in igneous rocks from Jamestown, Colorado. GSA Bulletin 1942;; 53 (5): 765–814. doi: https://doi.org/10.1130/GSAB-53-765 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 SocietyGSA Bulletin Search Advanced Search Abstract Spectrographic analyses of a group of igneous rocks and their constituent minerals from Jamestown, Boulder County, Colorado, revealed:Qualitative AnalysesRocks: Each, regardless of age, is distinguishable by variations in content of certain elements (Sc, La, Ce, Nd, Zr, V, Cr, Co, Ni, Pb, and Zn). Comparison with several Massachusetts rocks emphasizes the province relationship.Minerals: Minor elements occur systematically. Sr is highest in K and Ca minerals (particularly feldspars); Ba in K minerals (potash feldspar and hornblende). All quartz and sphenes contain Al. Sc is most abundant in Mg and ferrous Fe minerals (micas and hornblende). Sphenes contain a remarkable proportion of rare earths. Ti, Mn, V, and Cr are concentrated in the dark minerals and muscovite. Ni and Co occur almost exclusively in biotite.Quantitative AnalysesQuantitative analyses substantiate all conclusions based on the qualitative work.Minerals: Characteristic minor elements of each mineral vary from rock to rock. The SrO : BaO ratios decrease numerically in the order of plagioclases, biotites, K-feldspars, and muscovites. Pegmatite K-feldspars have much larger SrO : BaO ratios than parent rock samples. This is explained by temperature-crystal structure relations. Qualitatively and quantitatively each pegmatite mineral bears an average of less of almost every minor constituent than the same mineral in the parent rock. This also is explained by temperature-crystal structure relations.The minor constituents are probably present in solid solution. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.