Browsing by Subject "Trace elements"

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  • Heinonen, Jussi S.; Bohrson, Wendy A.; Spera, Frank J.; Brown, Guy A.; Scruggs, Melissa A.; Adams, Jenna V. (2020)
    The Magma Chamber Simulator (MCS) is a thermodynamic model that computes the phase, thermal, and compositional evolution of a multiphase–multicomponent system of a Fractionally Crystallizing resident body of magma (i.e., melt ± solids ± fluid), linked wallrock that may either be assimilated as Anatectic melts or wholesale as Stoped blocks, and multiple Recharge reservoirs (RnASnFC system, where n is the number of user-selected recharge events). MCS calculations occur in two stages; the first utilizes mass and energy balance to produce thermodynamically constrained major element and phase equilibria information for an RnASnFC system; this tool is informally called MCS-PhaseEQ, and is described in a companion paper (Bohrson et al. 2020). The second stage of modeling, called MCS-Traces, calculates the RASFC evolution of up to 48 trace elements and seven radiogenic and one stable isotopic system (Sr, Nd, Hf, 3xPb, Os, and O) for the resident melt. In addition, trace element concentrations are calculated for bulk residual wallrock and each solid (± fluid) phase in the cumulate reservoir and residual wallrock. Input consists of (1) initial trace element concentrations and isotope ratios for the parental melt, wallrock, and recharge magmas/stoped wallrock blocks and (2) solid-melt and solid–fluid partition coefficients (optional temperature-dependence) for stable phases in the resident magma and residual wallrock. Output can be easily read and processed from tabulated worksheets. We provide trace element and isotopic results for the same example cases (FC, R2FC, AFC, S2FC, and R2AFC) presented in the companion paper. These simulations show that recharge processes can be difficult to recognize based on trace element data alone unless there is an independent reference frame of successive recharge events or if serial recharge magmas are sufficiently distinct in composition relative to the parental magma or magmas on the fractionation trend. In contrast, assimilation of wallrock is likely to have a notable effect on incompatible trace element and isotopic compositions of the contaminated resident melt. The magnitude of these effects depends on several factors incorporated into both stages of MCS calculations (e.g., phase equilibria, trace element partitioning, style of assimilation, and geochemistry of the starting materials). Significantly, the effects of assimilation can be counterintuitive and very different from simple scenarios (e.g., bulk mixing of magma and wallrock) that do not take account phase equilibria. Considerable caution should be practiced in ruling out potential assimilation scenarios in natural systems based upon simple geochemical “rules of thumb”. The lack of simplistic responses to open-system processes underscores the need for thermodynamical RASFC models that take into account mass and energy conservation. MCS-Traces provides an unprecedented and detailed framework for utilizing thermodynamic constraints and element partitioning to document trace element and isotopic evolution of igneous systems. Continued development of the Magma Chamber Simulator will focus on easier accessibility and additional capabilities that will allow the tool to better reproduce the documented natural complexities of open-system magmatic processes.
  • Talvio, Karo; Kanninen, Katja M.; White, Anthony R.; Koistinaho, Jari; Castren, Maija L. (2021)
    Trace elements have important functions in several processes involved in cellular homeostasis and survival. Dysfunctional metal ion homeostasis can make an important impact on cellular defence mechanisms. We assessed the concentrations of 23 trace minerals in different tissues (brain, spleen, heart and liver) of Fmr1 knockout (KO) mice that display the main phenotype of Fragile X syndrome (FXS), an intellectual disability syndrome and the best-known monogenic model of autism spectrum disorder (ASD). Altogether, seven minerals-Cu, Fe, K, Mg, Mn, Na, and P-were above the detection limit with the analysis revealing increased iron content in the heart of Fmr1 KO mice. In addition, levels of iron were higher in the cerebellum of the transgenic mouse when compared to wild type controls. These results implicate a role for dysregulated iron homeostasis in FXS tissues and suggest that defective iron-related mechanisms contribute to increased tissue vulnerability in FXS.
  • Talvio, Karo; Kanninen, Katja; White, Anthony; Koistinaho, Jari; Castrén, Maija (Helsingin yliopisto, 2021)
    Biometalleilla on merkittävä rooli solujen ja kudosten toiminnassa. Ne ovat monen entsyymin toiminnassa elintärkeitä, mutta toisaalta solut pyrkivät pitämään niiden pitoisuudet tarkoissa rajoissa. Metallin yli- tai alimäärä voi joko itsessään vaikeuttaa solujen normaalia toimintaa tai olla merkki epätavallisesta metaboliasta. Fragile X-oireyhtymä on monogeeninen kehitysvammaisuutta aiheuttava perinnällinen sairaus, joka johtuu FMRP-proteiinin puutoksesta. Oireyhtymä on mahdollisesti yleisin periytyvän autismin syy. 23 metallin kudospitoisuudet mitattiin Fragile X-oireyhtymää mallintavan hiirimallin ja kontrollihiirten pikkuaivoista, isoaivokuorelta, maksasta, sydämestä ja pernasta induktiivisesti kytketty plasma -massaspektrometrillä. Seitsemän metallin – Cu, Fe, K, Mg, Mn, Na ja P – pitoisuudet olivat mittausrajan yläpuolella. Hiirimallin sydämen ja pikkuaivojen rautapitoisuudet olivat korkeampia kuin kontrollihiirten vastaavista kudoksista mitatut arvot. Löydösten merkitsevyydet olivat kuitenkin statistisesti raja-arvoisia. PCA-analyysi vahvisti käsitystä muuttuneesta metallihomeostaasista hiirimallin sydämessä, ja toisaalta Fragile X-oireyhtymän aiheuttavan FMRP-proteiinin mutaatiot on aiemmin liitetty ihmisillä pikkuaivojen rautakertymiin. Tutkimus kärsii pienen näytemäärän takia alhaisesta voimasta, mutta rautamuutokset sopivat aiemmin kuvattuun FMRP-proteiiniin liitettyyn inflammaatioon. Tässä tutkimuksessa sekä aiemmissa julkaisuissa kuvattu biometallien epätasapaino edellyttää lisätutkimusta aiheesta, sillä metalleja sisältäviä lisäravinteita kokeillaan usein hoidoksi hermoston kehityshäiriöissä.
  • Gautam, Mukesh Kumar; Lee, Kwang-Sik; Berg, Bjorn; Song, Byeong-Yeol (2020)
    Evaluating the decomposition-based change dynamics of various elements in plant litter is important for improving our understanding about their biogeochemical cycling in ecosystems. We have studied the concentrations of major, trace, and rare earth elements (REEs) (34 elements) in green tissue litter, and soil and their dynamics in the decomposing litters of successional annual fleabane (Erigeron annuus) and silvergrass (Miscanthus sinensis). Concentrations of major and trace elements in the litter of annual fleabane were 1.02-2.71 times higher compared to silvergrass. For REEs the difference between the two litter types for elements studied was in the range of 1.02-1.29 times. Both the litters showed a general decrease in the concentrations of elements in the initial stages of decomposition (60-90 days). All the major and trace elements (except for Na) in silvergrass showed a net increase in concentration at the end of the decomposition study (48.9-52.5% accumulated mass loss). Contrastingly, a few trace elements (Mn, Mo, Sr, Zn, Sb, and Cd) in annual fleabane showed a net decrease in their concentrations. For REEs, there was an increase in concentrations as well as in net amounts in both litter types. Similarities observed in the dynamics together with high and significant correlations among them likely suggest their common source. The higher concentrations of REEs in soil likely suggest its role in the net increase in REEs' concentrations and amount in litter during decomposition. (C) 2020 Elsevier B.V. All rights reserved.
  • Nikkola, Paavo; Gudfinnsson, Gudmundur H.; Bali, Eniko; Ramo, O. Tapani; Fusswinkel, Tobias; Thordarson, Thorvaldur (2019)
    We present new high-precision major and trace element data on olivine macrocrysts from various volcano-tectonic settings in Iceland and use these data as a proxy for mantle mode and melting conditions. Within individual sampling sites examined (seven lavas and one tephra) olivine-dominated fractional crystallization, magma mixing and diffusive re-equilibration control observed variability in olivine composition. High-pressure fractional crystallization of clinopyroxene may have lowered Ca and increased Fe/Mn in one olivine population and subsolidus diffusion of Ni and Fe-Mg affected the mantle-derived Ni/Fo ratio in some compositionally zoned olivine macrocrysts. Interestingly, magmas erupted at the southern tip of the Eastern Volcanic Zone (SEVZ), South Iceland, have olivines with elevated Ni and low Mn and Ca contents compared to olivines from elsewhere in Iceland, and some of the SEVZ olivines have relatively low Sc and V and high Cr, Ti, Zn, Cu and Li in comparison to depleted Iceland rift tholeiite. In these olivines, the high Ni and low Mn indicate relatively deep melting (P-final>1.4GPa,similar to 45km), Sc, Ti and V are compatible with low-degree melts of lherzolite mantle, and elevated Zn may suggest modal (low-olivine) or geochemical (high Zn) enrichment in the source. The SEVZ olivine macrocrysts probably crystallized from magmas derived from olivine-bearing but relatively deep, enriched and fertile parts of the sub-Icelandic mantle, and indicate swift ascent of magma through the SEVZ lithosphere.