Redistribution Of Trace Elements Research Articles

Metallothionein is induced and trace element balance changed in target organs of a common viral infection.

In experimental studies on the common human coxsackievirus B type 3 (CB3) infection, administered cadmium (Cd) is known to accumulate in the liver and kidneys. CB3 adapted to Balb/c mice was used to study whether infection affects the Cd-binding protein, metallothionein (MT) and if this alters the normal physiological trace element balance in the liver, kidney, spleen and brain. On day 3 of infection, degradation of liver proteins (44%, P<0.01) occurred, whereas in the spleen, protein increased (63%, P<0.05). The infection increased MT five-fold (P<0.01) in liver and kidneys, and in spleen by 34% (P<0.05). A redistribution of Cd and copper (Cu) from the liver to the kidney was associated with this increase in MT, resulting in an increased (P<0.01) kidney/liver ratio for both elements. The infection increased the zinc (Zn) concentration more in the kidney than in the liver, but the kidney/liver ratio was not significantly affected. Results show that MT is increased in several organs during the early phase of infection and is associated with redistribution of both essential and non-essential trace elements. This may be a normal response in common infections that could adversely influence the pathogenesis when the host is concomitantly exposed to potentially toxic trace elements, even at levels in the physiological range.

Redistribution of trace elements during prograde metamorphism from lawsonite blueschist to eclogite facies; implications for deep subduction-zone processes

The transfer of fluid and elements from subducting crust to the overlying mantle wedge is a fundamental process affecting arc magmatism and the chemical differentiation of the Earth. While the production of fluid by breakdown of hydrous minerals is well understood, the liberation of trace elements remains generally unconstrained. In this paper, we evaluate the behaviour of trace elements during prograde metamorphism and dehydration using samples of high-pressure, low-temperature metamorphic rocks from New Caledonia. Samples examined include mafic and pelitic rock-types that range in grade from lawsonite blueschist to eclogite facies, and represent typical lithologies of subducting crust. Under lawsonite blueschist facies conditions, the low temperatures of metamorphism inhibit equilibrium partitioning between metamorphic minerals and allow for the persistence of igneous and detrital minerals. Despite this, the most important hosts for trace-elements include lawsonite, (REE, Pb, Sr), titanite (REE, Nb, Ta), allanite (LREE, U, Th), phengite (LILE) and zircon (Zr, Hf). At epidote blueschist to eclogite facies conditions, trace-element equilibrium may be attained and epidote (REE, Sr, Th, U, Pb), garnet (HREE), rutile (Nb, Ta), phengite (LILE) and zircon (Zr, Hf) are the major trace-element hosts. Chlorite, albite, amphibole and omphacite contain very low concentrations of the investigated trace elements. The comparison of mineral trace-element data and bulk-rock data at different metamorphic grades indicates that trace elements are not liberated in significant quantities by prograde metamorphism up to eclogite facies. Combining our mineral trace-element data with established phase equilibria, we show that the trace elements considered are retained by newly-formed major and accessory minerals during mineral breakdown reactions to depths of up to 150 km. In contrast, significant volumes of fluid are released by dehydration reactions. Therefore, there is a decoupling of fluid release and trace element release in subducting slabs. We suggest that the flux of trace elements from the slab is not simply linked to mineral breakdown, but results from complex fluid-rock interactions and fluid-assisted partial melting in the slab.

Residence and redistribution of REE, Y, Zr, Th and U during granulite-facies metamorphism: behaviour of accessory and major phases in peraluminous granulites of central Spain

Accessory minerals are thought to play a key role in controlling the behaviour of certain trace elements such as REE, Y, Zr, Th and U during crustal melting processes under high-grade metamorphic conditions. Although this is probably the case at middle crustal levels, when a comparison is made with granulite-facies lower crustal levels, differences are seen in trace element behaviour between accessory minerals and some major phases. Such a comparison can be made in Central Spain where two granulite-facies terranes have equilibrated under slightly different metamorphic conditions and where lower crustal xenoliths are also found. Differences in texture and chemical composition between accessory phases found in leucosomes and leucogranites and those of melanosomes and protholiths indicate that most of the accessory minerals in melt-rich migmatites are newly crystallized. This implies that an important redistribution of trace elements occurs during the early stages of granulite-facies metamorphism. In addition, the textural position of the accessory minerals with respect to the major phases is crucial in the redistribution of trace elements when melting proceeds via biotite dehydration melting reactions. In granulitic xenoliths from lower crustal levels, the situation seems to be different, as major minerals show high concentration of certain trace elements, the distribution of which is thus controlled by reactions involving final consumption of Al-Ti-phlogopite. A marked redistribution of HREE–Y–Zr between garnet and xenotime (where present) and zircon, but also of LREE between feldspars (K-feldspar and plagioclase) and monazite, is suggested.

Geochemical research of the impact of Se–Cu–Mo–V-bearing coal layers on the environment in Pingli County, Shaanxi Province, China

This paper presents a geochemical study on the impact of Se–Cu–Mo–V-bearing coal layers on the environment in Pingli County, Shaanxi Province, China. Analysed samples for environmental geochemical study (rock, soil and edible plant) were collected from the abandoned Dragon Village coal mine on the northern bank of the Pingli River, and the Shanliya coal mine area still in exploitation. Experiments on coal combustion were made in order to determine the amount of Se released from coal burned by local inhabitants. There are three main ways by which coal beds enhance Se, Cu, Mo, and V in the environment in the study area. First of all, supergene geological processes involving soils derived from the Se-bearing rocks and the weathering of coal are the main control on the redistribution of Se, Mo, and other trace elements in Pingli County. Coal seams in the Shanliya contain as much as 48 μg g −1 Se, 452 μg g −1 Mo, and 335 μg g −1 Cu, whereas the soil has 0.85–7.10 μg g −1 Se, 46–227 μg g −1 Cu, and 8–29 μg g −1 Mo. Selenium is enriched in the weathering crust of coal beds with values of 88.4 μg g −1 Se in a calcareous sinter from the top of the weathering zone. Therefore, edible plants possible may accumulate Se, Zn, Cu, and Mo, for instance, with value above 20 μg g −1 Cu from sesame and peanut growing in the area. Second, coal beds in the Dragon Village coal mine contain 96 μg g −1 Se while the Se concentration of soils is high, ranging from 27 to 29.5 μg g −1 Se. As a result, some plants have high Se contents (0.08–28 μg g −1 Se). Variations in Se and Mo contents of the same plant species are due to large-scale geographical variations in environmental Se and Mo of soils and rocks. Finally, it is proposed that most of Se in the coal is released into atmosphere after combustion. The percentage of Se released from coal combustion containing 52.8–53 μg g −1 Se from the Shanliya mine is 78% on average, whereas that from the coal containing 73–85 μg g −1 Se from Dragon Village is 98%. Whenever it rains, the Se released in the atmosphere could recycle back to soils and plants on the ground.

Redistribution Behavior of Trace Elements during Internal Oxidation of an Fe-6mol%Si Alloy at 1123 K

SIMS and XPS have been applied to characterize the elemental distribution in the internal oxidation zone of an Fe-6mol% Si alloy. Internal oxidation behavior agrees well with predictions based on the thermodynamic data of oxidation. Redistribution of trace elements is deeply related to internal oxidation and interface segregation.

Gabbro-derived Granulites from the Northern Apennines (Italy): Evidence for Lower-crustal Emplacement of Tholeiitic Liquids in Post-Variscan Times

Apennines and the Western Alps. The protoliths of the Fe–TiThe mafic granulites from the Northern Apennines commonly contain oxide-bearing mafic granulites can be related to the least evolved significant amounts of either olivine or Fe–Ti-oxide phases. On the rocks through fractional crystallization and assimilation of crustal basis of mineralogy and whole-rock major and trace element material. The felsic granulites probably represent anatectic and compositions, their protoliths are recognized as cumulus rocks derived migmatitic rocks resulting from multi-stage melting of lower-crustal from variably evolved tholeiitic liquids. Clinopyroxenes from the basement rocks. olivine-bearing rocks show peculiar trace element compositions (e.g. low amounts of Cr, Zr and lanthanides, coupled with relatively high Sr concentrations) that record a process of granulite-facies trace element redistribution controlled by a reaction between olivine and

Volatile-induced transport of HFSE, REE, Th and U in arc magmas: evidence from zirconolite-bearing vesicles in potassic lavas of Lewotolo volcano (Indonesia)

Potassium-rich calc-alkaline lavas of Lewotolo volcano, situated in the East Sunda Arc, Indonesia, contain the rare mineral zirconolite (CaZrTi2O7). Samples in which tiny grains of this mineral (3–25 μm in size) were found span the entire range of lava compositions (47–62 wt% SiO2). To the best of our knowledge, this is the first record of primary zirconolite in juvenile arc volcanics. The mineral forms part of a vesicle-filling assemblage consisting of a network of quenched feldspar crystals and an SiO2 phase, probably cristobalite. High contents of Th, U and REE (up to 9.3, 4.3 and 15.6 wt% oxide respectively) and very high Fe contents (up to 13.5 wt% Fe2O3) distinguish these zirconolites from those of other rock types. The extraction of volatile-rich phases with changing compositions in successive stages is considered to be responsible for the zirconolite formation. We hypothesise that a fluid capable of transporting HFSE, REE, Th and U was extracted from the magma and (partly) crystallised within voids which had formed earlier upon saturation of an aqueous fluid. Assuming that zirconolite compositions largely reflect trace metal contents of the coexisting fluid phase, significant amounts of `immobile' elements must have been transported on a macroscopic scale. Our findings thus point to a late-stage transfer of HFSE, REE, Th and U between different domains in a cooling magma body. Such a volatile-induced redistribution of trace elements at shallow levels of high-K volcanic systems may be significant for conventional geochemical modelling of magma evolution and for Th–U disequilibrium studies.

Redistribution of Trace Elements from Contaminated Sediments of Lake Coeur d'Alene during Oxygenation

AbstractSediments of Coeur d'Alene Lake in northern Idaho are contaminated with heavy metals as a result of mining in the Coeur d'Alene River basin. Dredging and disposal operations have been suggested as a possible means of environmental remediation; thus, detailed knowledge is required as to how sediment oxygenation can result in the redistribution of trace elements. To simulate changing physicochemical soil conditions, stirred batch experiments were conducted using fresh sediment core material retrieved from the lake. Fifty grams of sediment were added to 750 mL of double deionized water and mixed while being oxygenated for 260 h. The following parameters were monitored as a function of time: pH and Eh, contaminant trace‐element release into the aqueous phase, and metal abundance within operationally defined fractions of the solid phase: magnesium chloride (exchangeable), sodium hypochlorite (organic), sodium acetate‐acetic acid (carbonate), ammonium oxalate in the dark (non‐crystalline), hydroxylamine hydrochloride (crystalline), and potassium perchlorate‐hydrochloric‐nitric acid (sulfidic) extractable sediment fractions. In all trials, levels of aqueous‐phase Zn remained high throughout the simulations (6.60 mg L−1) and were highly correlated (sigma value = 0.95) with Mn. Oxygenation and disturbance resulted in a shift in trace element partitioning from the sodium hypochlorite (organic) and potassium perchlorate‐hydrochloric‐nitric acid extractable (sulfidic) fractions into the ammonium oxalate in the dark (noncrystalline) extractable fraction. Overall, these results indicate that oxygenation and agitation of anaerobic sediment results in Zn release into solution with concomitant redistribution of trace elements in the solid‐phase.

EXPERIMENTAL DETERMINATION OF GARNET-SPINEL COEXISTING LHERZOLITE FACIES AND TRACE ELEMENT DISTRIBUTION

The pressure-temperature location of garnet and spinel lherzolite facies boundary is often critical for understanding mantle dynamics. We have investigated the boundary by experiments using natural starting materials. For compositions close to the model primitive mantle at constant temperature of 1360°C, garnet-in boundary is approximately 2.3 GPa while spinel-out is at approximately 2.6 GPa. The redistribution of trace elements during the garnet break down reaction (i.e. olivine[ol] + garnet[gt] = orthopyroxene[opx] + clinopyroxene[cpx] + spinel[sp]) lags behind phase equilibrium and product opx and cpx “inherit” the REE abundances from reactant garnet. Diffusion equilibration for trace elements takes several hundred thousand years for pyroxenes over distance of 500µm at 1200°C. The pressure-temperature data for garnet-spinel transformation are inadequate particularly under near solidus conditions in natural peridotite compositions. Previous experimental studies have demonstrated that compositional effects on the location of garnet-spinel facies boundary in simple systems were considerable (e.g. Nickel, 1986; O’Neill, 1981). Addition of chrome shifts the boundary to higher pressures, but the data are not sufficient for extrapolating the results to natural compositions. For natural systems, experimental studies of the transformation boundary are limited in number (Jenkins and Newton, 1979; O’Hara et al., 1971) and their results span over a range approximately 10 kbar. Furthermore, experimental results for the transformation boundary near solidus (above 1300°C) do not exist. Our experiments were aimed at determining where garnet and spinel become stable at near solidus condition (e.g. 1360°C). In addition, the phase rule predicts a range of pressure- temperature conditions for the existence of transitional garnet-spinel lherzolite zone, because the degree of freedom is more than two for the garnet break down reaction in the natural system. This suggests that the garnet-in boundary is located toward the lower pressures than the spinel-out boundary. We circumvent the problem, that is caused by sluggishness of reaction, by monitoring rates of the garnet breakdown and growth reactions. Model parameters corresponding to chemical affinity are determined from time dependent progresses of the reaction. These parameters are used to extrapolate the condition where reaction rate is zero, that is equilibrium. The results show that at 1360°C garnet-in boundary is located at 0.3 GPa lower pressure than spinelout boundary. Garnet and spinel can coexist in the range of pressure. It should be noted that the 0.3 GPa pressure range for the coexistence is difficult to resolve by the conventional reversal reaction method (Koga et al., 1998). Trace elements that reside in garnet have to be redistributed during the garnet break-down reaction. Peridotite samples that have experienced the decompression often display incomplete trace element redistribution in newly formed minerals. Trace element measurements on experimental charges demonstrate that product opx and cpx “inherit” the trace element abundance from the reactant garnet, and there are no recognizable differences in abundance of trace element between opx and cpx. Thus, while major element abundances in pyroxenes are in equilibrium as demonstrated by experimentally calibrated geothermobarometers, trace element redistribution is incomplete. This may be caused by the differences in diffusivities of major and trace elements. The disequilibrium trace element distribution similar to experimental results could be expected in rocks under went rapid decompression. Indeed, The trace element distribution among fine grained rims around garnet consisting opx, cpx, and spinel in peridotite xenoliths from Lashaine, Tanzania closely resembles experimental results. Time scales for equilibration of pyroxenes can be modeled by diffusion. A model involving a spherical grain with a constant composition boundary, and a model with adjacent finite length slabs of opx and cpx, are compared under various diffusivities and boundary conditions in cooling histories. The results show persistence of disequilibrium for 7-800k years at high temperature (1200°C), and fractionated zoning of rare earth elements due to D(Yb) > D(La). Starting materials are mineral separates from garnet lherzolite from Pali Aike, Chile for garnet break down and spinel lherzolite from Kilbourne Hole, USA for garnet production reaction. Experiments are conducted at the conditions at 1360°C and from 1.8 to 3.0 GPa, with the run duration spanning form 2 to 200 hours. The run conditions were achieved by 2.54 cm diameter piston-cylinder type apparatus, with Ba- CO3 as pressure transmitting medium. Pressure calibrations were done by the CaTs break-down reaction (Hays, 1967) and An-Sp lherzolite transformation for CMAS system at subsolidus and above solidus conditions (Kushiro and Yoder, 1966). Volume fractions of product phases are measured from the digitally captured back-scattered electron images with the combination of x-ray images. Major element compositions are measured by electron probe. Trace elements abundances are measured by ion probe.

Transfer, pathways, enrichment and discharge of trace elements in the pulp industry measured by means of neutron activation analysis

In Norway trace elements are transferred from terrestrial ecosystems to coastal sea water via the forest industry. Raw materials (wood, bark and freshwater) contain relatively low concentrations of trace elements, but due to the high volume, processed wood and bark are the main sources of element input to the industrial pulp production process. Up to 80% of the elements enter the pulp process via wood. Thus, the annual flux of trace elements can be regarded as substantial. The purpose of this investigation is to study transfer, redistribution, enrichment and discharges of trace elements from the pulp industry. Instrumental neutron activation analysis (INAA), is used to determine the concentrations of Cd, Ce, Co, Cs, Eu, Fe, La, Rb, Sc, Sm, Sr and Zn in samples of the different raw materials, process liquors, waste and waste water and products from processing. Lead, Cu and Ni were measured by means of atomic absorption spectroscopy with graphite furnace (GFAAS) and inductive coupled plasma atomic emission spectroscopy (ICP-AES). Recycling of chemicals leads to enrichment of trace elements. Corrosion of tubes and tanks gives increased concentration of Pb, Cu and transition elements in the re-cycling circles. For all other elements the process reaches a `steady state'; hence the annual input is equal to the annual output (kg/year). The products contained very low levels of trace elements. For all the trace elements<20% of the total output from the process and for some elements only 5%, were found in the products. Discharges of trace elements from the investigated pulp production plant to the fjord reached 70% of the annual trace element output in 1993 while the remaining fraction was stored as waste.

Biotic and Abiotic Controls on Black Shale Diagenesis and Redistribution of Trace Elements

The Llanvirn-Llandeilo/Caradoc black shales of southwest Wales, U.K. have undergone a multistage diagenetic history (Lev et al. , 1998). The paragenetic sequence from these rocks requires early and late diagenetic events that have redistributed trace and major elements and left an overprint on the Sm-Nd and U-Pb whole rock isotopic systems. The types of reactions essential to produce these mineralogic and geochemical changes require both biotic and late abiotic processes. The relative importance and timing of these processes can be evaluated by examining their net effect on the mineralogy and geochemistry of the whole rock P a r a g e n e t i c s e q u e n c e o f t h e L l a n v i r n L l a n d e i l o C a r a d o c b lack shales

The relationship between websterite and peridotite in the Balmuccia peridotite massif (NW Italy) as revealed by trace element variations in clinopyroxene

Clinopyroxenes from peridotite, Cr-diopside and Al-augite websterites of the Balmuccia massif have been analyzed by ion-probe for REE, Sr, Zr, Ti, V, Y, Sc and Cr. In the peridotites, the REE pattern of clinopyroxene varies from markedly LREE depleted [(Ce/Yb)n=0.03] to moderately LREE enriched [(Ce/Yb)n=1.96]. Clinopyroxenes of the Cr-Diopside suite vary from moderately LREE depleted to enriched [(Ce/Yb)n=0.53–1.36], but HREE are always depleted with respect to MREE [(Sm/Yb)n=1.19–2.06]. The clinopyroxenes of the Al-Augite dikes have higher trace element concentrations and are relatively depeleted in LREE. Two types of peridotite to websterite transitions have been documented. One type characterizes the transitions from peridotite to Cr-diopside websterite. The depletion of peridotite increases, and cpx “fertility” decreases, towards the contact; i.e. REE from Sm-Eu to Yb and Ti, V, Y, Sc and Cr in cpx define abundance trends consistent with melt extraction. LREE, Sr, and perhaps Zr, on the contrary, increase in the contact region over a distance of 0–40 cm. The variation of the latter elements and of CaO and Al2O3 from peridotite to websterite is smooth, whereas it is steep for the other elements. Alumina, HREE, Y and Sc are lower, Ca is higher, and the MREE/HREE pattern is steeper in the clinopyroxene of the websterite with respect to peridotite. In the second type of transition, as the contact is approached, there is an increase in modal cpx and decrease of the opx/cpx ratio. Cpx trace element patterns are similar in peridotite and websterite. This transition is generally at the Al-augite websterite contacts, but also was found at two Cr-diopside contacts. The wall rock depletion of the first transition type is interpreted as caused by melt extraction induced by intrusion of melts derived from deeper mantle (garnet-facies), whereas the LREE and Sr variation is interpreted in terms of diffusive redistribution of trace elements after emplacement of the dikes and after the modal clinopyroxene has been removed from the peridotite. Diffusive exchange occurred under stagnant conditions but in the presence of a partial melt or a “metamorphic fluid”, rather than under dry subsolidus conditions. There is no conclusive evidence favouring either a partial melt or an aqueous fluid as a medium for diffusive transport. However, we favour transport via a fluid phase because the presence of such a fluid is indicated by ubiquitous traces of amphibole in the peridotite. The second transition type is interpreted in terms of melt infiltration and re-equilibration of the melt with the peridotite matrix.

Trace element redistribution in high‐temperature deformed gabbros from East Ligurian ophiolites (Northern Apennines, Italy): constraints on the origin of syndeformation fluids

Abstract Mg‐gabbros from East Ligurian ophiolites (Northern Apennines, Italy) display a high‐temperature/low‐pressure recrystallization localized along ductile shear zones. In deformed gabbros, the igneous diopside is recrystallized into granoblastic aggregates of neoblastic diopside and minor red‐brown amphibole. The latter displays a pargasitic composition, with high amounts of AlIV Na(A) and Ti (± 1.8, 0.7 and 0.4 atoms per formula unit, respectively). Major element composition of neoblastic minerals highlight equilibration temperature conditions in the range 800–950° C. Red‐brown Ti‐pargasite also occurs as a minor interstitial constituent, presumably growing from a residual trapped liquid, in the differentiated lithologies (Fe‐Ti‐diorites) of the plutonic ophiolitic complex.By means of ion microprobe (SIMS technique), rare earth (La, Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb) and selected trace elements (Sr, Y, Cr, V, Sc, Zr, Ti) have been analysed in igneous and neoblastic diopside, as well as in Ti‐pargasites. Ti‐pargasites have also been analysed for F and Cl, and compared with the halogen composition of the amphiboles, mainly hornblendes to actinolites, which are related to the subsequent low‐temperature brittle evolution.Neoblastic Ti‐pargasite from deformed Mg‐gabbros bears close compositional similarities with igneous Ti‐pargasite from undeformed Fe‐Ti‐diorites, whereas it is geochemically distinct from the amphiboles post‐dating the ductile event. In particular, Ti‐pargasites have relatively high contents of F, REE, Y, Zr and Sr, which are not consistent with crystallization in the presence of seawater‐derived hydrothermal fluids.High‐grade recrystallization probably developed in the presence of volatile‐rich igneous fluids, either trapped between the cumulus minerals or injected into the ductile shear zones from outside the local system. An alternative hypothesis comprises the absence of fluid phase and the development of ductile shear zones in Ti‐pargasite‐rich layers. The petrological features of deformed gabbros recovered from present‐day slow‐spreading ridges and fracture zones bear close similarities with the investigated ophiolitic metagabbros. In East Ligurian ophiolites, high‐grade ductile shear zones have been related to the initial stages of the uplift of the gabbro‐peridotite complex to the sea‐floor.

Trace and rare earth element content of white clay soils of the Three River Plain, Heilongjiang Province, P.R. China

Three representative pedons of white clay soils in the Three River Plain, Heilongjiang Province, P.R. China were sampled to establish background levels of trace elements and rare earth elements (REE) and to evaluate pedogenic redistribution of these elements. Trace elements and REE in soil samples and clay separates were measured by instrumental neutron activation analysis. New information was obtained for the background levels and pedogenic behavior of 20 trace elements and 10 REE. Cl, Br, I and Hg were enriched in the Ah horizon. Elements having an adsorption affinity for Mn and Fe oxyhydroxides (As, Co and Mn) were concentrated in the E horizon. Elements associated with clay minerals (Cr, Rb, V and Zn) were elevated in soil samples from the illuvial horizon, while elements present in resistant minerals (Sr, Ti, Hf and Zr) had relatively uniform profile distributions. Possible chemical causes of the trace element redistribution and partitioning are also discussed in the paper. REE were enriched in clay fractions compared to whole soil. Ce positive anomalies seen in normalized curves of REE for the E horizon were attributed to precipitation and accumulation of the element in pedogenic Fe-Mn nodules. The Gd break, even-odd and tetrad effects were present in normalized curves, which indicates fractionation of REE during weathering. The high ratio of light REE (sum La) to heavy REE (sum Lu) for the soil can be attributed to a warm, humid geochemical weathering environment in the past.

Chemical diagenesis and dolomitization of paleozoic high-Mg calcite crinoids

Geochemical analyses suggest that during early diagenesis, shortly after death and disarticulation of the organism, the stroma of crinoids is rapidly filled by cement. Skeletal port space is only preserved in specimens which were rapidly buried and sealed in either asphalt-impregnated or shale formations. Cement-filling of the stroma and subsequent alteration of the skeletal high-Mg calcite to diagenetic low-Mg calcite generally obliterates original microstructures and mineralogy. These changes are accompanied by redistribution of trace elements and stable isotopes, and lead to increases for δ13C, Mn and Fe by factors of 7 to 140. At the same time Mg, Sr, Na, δ18O and in some instances δ13C decrease by factors ranging from 26 to 1.5. No specific trends were detected for Al, Cu, Ni and Zn. Multiple and discontinuous chemical trends of the sample populations argue for the ‘stepwise’ alteration of originally biogenic high-Mg calcite.

The redistribution of trace and minor elements during coal liquefaction

AbstractRadioactivation analysis of four sets of coal liquefaction feed and product materials provided information on the concentrations of forty trace and minor elements. Coal‐derived oil was found to have low levels of most elements, comparable to crude petroleum. Aqueous process effluents were shown to have potentially troublesome levels, especially of Cr and Ba. The concentration data derived in this study and relevant process data were combined to construct elemental mass balances around the liquefaction process; these varied widely between about 80 and 140%, depending mostly on analytical errors. Enrichment of chromium and other transition metals in the conversion residues indicated a possible source through equipment erosion while consistent depletion of barium suggested a loss to aqueous stream particulate matter or possible reactor deposits.

Trace Element and Salt Movement in Retorted Oil Shale Disposal Sites

AbstractThe direction and amount of salt and trace element movement within retorted shale disposal piles is a major environmental concern. This study examines the redistribution of soluble salts and trace elements (As, B, Cd, Cu, F, Fe, Mn, Mo, Na, Ni, Pb, Se, and Zn) in retorted shale test plots with different topsoil treatments 6 yr after construction. Topsoil treatments included no topsoil, no topsoil and leached with 76‐cm water, 30‐cm topsoil, 60‐cm topsoil, 90‐cm topsoil, 60‐cm topsoil and capillary barrier, and a disturbed soil control (no retorted shale). Soluble salts (especially Na salts) and F showed considerable movement both upwards and downwards in the profiles. Molybdenum showed some movement in both directions. The remaining elements showed little or no movement out of the shale layer. Increasing topsoil depths resulted in less salt or trace element movement in either direction. Use of a capillary barrier between the topsoil and retorted shale prevented upward migration of salts and trace elements. After 6 yr the exposed shale treatments (both leached and unleached) continued to have considerably higher salt and trace element contents than any other treatment. Because of limited rooting depths, deeper percolation of moisture is occurring on plots containing retorted shale than on the control plot.

Accessory minerals and the geochemical evolution of crustal magmatic systems: a summary and prospectus of experimental approaches

It has recently been recognized that accessory minerals in continental rocks may contain a substantial fraction of the whole-rock complement of trace elements and geochemically important isotopes. This observation is in itself interesting, but its importance is magnified many fold when one considers the possible consequences to the geochemical rearrangement that accompanies crustal melting. If, for example, an accessory phase is insoluble in early-formed partial melts, it may effectively retain in the residue many incompatible elements (e.g., REE) and daughter isotopes (e.g., radiogenic Pb) that would otherwise be partitioned into the melt. In addition, should an unmelted accessory mineral (e.g., zircon) be entrained in a departing melt fraction, it may carry with it radiogenic components (Pb∗, Nd 143, Hf 176) characteristic of the source region. The effectiveness of phases such as zircon, apatite, sphene, allanite-epidote, and monazite in the roles noted above can only be gauged from knowledge of the three “fundamental accessory-phase parameters,” i.e. (1) the solubilities of the accessory minerals in crustal melts; (2) the equilibrium mineral/liquid partition coefficients for the trace element and isotopes of interest; and (3) the diffusivities that govern the rates at which equilibrium will be approached. In general, these parameters can only be measured in laboratory experiments, and relatively few data have been accumulated to date. It does seem clear, however, that apatite generally is residual (insoluble) during crustal melting and zircon can be, depending on melting conditions and abundance of zircon in the source. Petrographic and geochemical studies indicate that monazite, allanite, and epidote may also be highly insoluble in some cases, but the specific circumstances that promote insolubility remain unknown. The few experimentally-determined partition coefficients now available for apatite and zircon agree qualitatively with natural rock data on mineral separates. However, preliminary diffusion measurements and inferences from natural systems suggest that trace-element and isotopic equilibrium between undissolved accessories and crustal melts is in fact rarely approached. Ironically, it is this very disequilibrium in the form of preserved diffusion profiles, that may afford the most information on time-temperature histories of melting events. Continued experimental interest in the fundamental accessory-phase parameters will eventually provide the tools that will enable rigorous assessment not only of the timing and duration of crustal melting episodes, but also of the extent of melting and re-distribution of trace elements and radiogenic isotopes.

Investigations of some trace elements in the Bay of Lim

Sea water was collected at several stations in the Bay of Lim at a depth of one meter below the surface, and before analysis, was filtered with 0.45-μm Millipore filters. Shallow water sediments were collected at the same locations. Humic acids used in this work were separated from near-shore sediments taken from various saline waters of the Bay of Lim. The prepared humic acids were then analysed for their elementary composition and also for positions of their hydrolytic products to obtain more data on how and to which characteristic part, the trace elements were related. The hydrolysis of humic acids was done by chemical methods in order to obtain four main components: amino acids, sugars, phenols and condensed benzene core. Neutron activation analysis was used for trace element analysis in evaporated portions of filtered sea water, sediments, soil, living organisms, humic acids and their hydrolytic products. This work was undertaken to obtain more data on the organic matter present in sediments and in seagrass flats, and also to collect more data on trace elements that are associated with typical and representative samples for the Bay of Lim. Analyses of trace elements associated with either humic acids or their hydrolytic products were performed with the purpose of gaining evidence as to which part of humic acids metals are bound. Humic acids or their decomposition products play an important role in the distribution and availability of a number of essential or nonessential trace elements. Results of this work indicate that humic acids influence the process of redistribution of trace elements in the investigated local coastal area.

Trace-element geochemistry of archean greenstone belts

Progressive alteration, diagenesis, and low-grade metamorphism of Archean greenstone belts often leads to redistribution of alkali and related trace elements. Transition metals and rare earths are relatively resistant to these processes and hence are most useful in evaluating petrologic problems. Depleted Archean tholeiite (DAT) exhibits flat REE distributions and low LIL-element contents while enriched Archean tholeiite (EAT) exhibits slightly enriched REE patterns and moderate LIL-element contents. DAT is grossly similar to modern rise and are tholeiites and EAT to cale-alkaline and oceanic island tholeiites. Archean and esites fall into three categories: depleted Archean andesite (DAA) exhibits flat REE patterns, negative Eu anomalies and low LIL-element contents; low-alkali Archean andesite (LAA) shows minor light REE enrichment and low LIL-element contents; and high-alkali Archean andesite (HAA) shows light REE enrichment and high LIL-element contents. LAA is grossly similar to modern cale-alkaline andesites, but DAA and HAA do not have modern analogues. Archean depleted siliceous volcanics (DSV) exhibit depletion in heavy REE and Y compared to modern siliceous volcanics whereas undepleted varieties (USV) are similar to modern ones. Almost all Archean volcanic rocks, regardless of composition, are enriched in transition metals compared to modern varieties. Archean graywackes are similar in composition to Phanerozoic graywackes. Rock associations in Archean greenstones suggest the existence of two tectonic settings. Magma model studies indicate that partial melting has left the strongest imprint on trace-element distributions in greenstone volcanics. Three magma source rocks are necessary (listed in order of decreasing importance): ultramafic rock, eclogite, and siliceous granulite. Trace-element studies of Archean graywackes indicate a mixed volcanic—granitic provenance with minor ultramafic contributions. Alkali and related trace-element contents of Archean volcanics have been interpreted in terms of both undepleted and depleted upper mantle sources. Preferential enrichment of transition metals in Archean volcanics may have resulted from upward movement of immiscible liquid sulfide droplets with Archean magmas, depleting the source area in these elements. Initial Sr isotope distributions in Archean volcanics indicate the upper mantle during the Archean was heterogeneous in terms of its Rb/Sr ratio.