Nature of soil organo-mineral assemblage examined by sequential density fractionation with and without sonication: Is allophanic soil different?

Geoderma ◽  
2015 ◽  
Vol 241-242 ◽  
pp. 295-305 ◽  
Author(s):  
Rota Wagai ◽  
Masako Kajiura ◽  
Maki Asano ◽  
Syuntaro Hiradate
Keyword(s):  
Mineral Assemblage ◽  
Density Fractionation ◽  
Allophanic Soil

scholarly journals Petrogenesis of a late-stage calc-alkaline granite in a giant S-type batholith: geochronology and Sr–Nd–Pb isotopes from the Nomatsaus granite (Donkerhoek batholith), Namibia

2021 ◽  
Author(s):  
S. Aspiotis ◽  
S. Jung ◽  
F. Hauff ◽  
R. L. Romer
Keyword(s):  
Partial Melting ◽  
Mineral Assemblage ◽  
Central Zone ◽  
Calc Alkaline ◽  
Pb Isotope ◽  
Alkaline Granite ◽  
Ti Oxides ◽  
Eu Anomaly ◽  
Environment Characteristic ◽  
Southern Central

AbstractThe late-tectonic 511.4 ± 0.6 Ma-old Nomatsaus intrusion (Donkerhoek batholith, Damara orogen, Namibia) consists of moderately peraluminous, magnesian, calc-alkalic to calcic granites similar to I-type granites worldwide. Major and trace-element variations and LREE and HREE concentrations in evolved rocks imply that the fractionated mineral assemblage includes biotite, Fe–Ti oxides, zircon, plagioclase and monazite. Increasing K2O abundance with increasing SiO2 suggests accumulation of K-feldspar; compatible with a small positive Eu anomaly in the most evolved rocks. In comparison with experimental data, the Nomatsaus granite was likely generated from meta-igneous sources of possibly dacitic composition that melted under water-undersaturated conditions (X H2O: 0.25–0.50) and at temperatures between 800 and 850 °C, compatible with the zircon and monazite saturation temperatures of 812 and 852 °C, respectively. The Nomatsaus granite has moderately radiogenic initial 87Sr/86Sr ratios (0.7067–0.7082), relatively radiogenic initial εNd values (− 2.9 to − 4.8) and moderately evolved Pb isotope ratios. Although initial Sr and Nd isotopic compositions of the granite do not vary with SiO2 or MgO contents, fSm/Nd and initial εNd values are negatively correlated indicating limited assimilation of crustal components during monazite-dominated fractional crystallization. The preferred petrogenetic model for the generation of the Nomatsaus granite involves a continent–continent collisional setting with stacking of crustal slices that in combination with high radioactive heat production rates heated the thickened crust, leading to the medium-P/high-T environment characteristic of the southern Central Zone of the Damara orogen. Such a setting promoted partial melting of metasedimentary sources during the initial stages of crustal heating, followed by the partial melting of meta-igneous rocks at mid-crustal levels at higher P–T conditions and relatively late in the orogenic evolution.

scholarly journals A New Radiocarbon Pretreatment Method for Molluscan Shell Using Density Fractionation of Carbonates in Bromoform

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1301-1311 ◽  
Author(s):  
Christopher M Russo ◽  
Jennifer A Tripp ◽  
Katerina Douka ◽  
Thomas F G Higham
Keyword(s):  
Radiocarbon Dating ◽  
Separation Technique ◽  
Archaeological Sites ◽  
Density Fractionation ◽  
Pretreatment Method ◽  
Density Separation ◽  
Molluscan Shell ◽  
Archaeological Artifacts ◽  
Organic Remains

Coastal archaeological sites that lack organic remains for radiocarbon dating are often abundant sources of molluscan shells. As a substitute for materials such as bone and charcoal, shells can be analyzed with 14C dating to determine a site's age. Despite their being convenient, non-mobile archaeological artifacts, molluscan shells are plagued by several issues, including carbonate remodeling, in which aragonite in shells is converted to calcite as predicted by thermodynamics. We present here a carbonate density separation technique that addresses the issue of carbonate remodeling. Using a density fractionation with bromoform, aragonite concentrations are enriched in shells that have undergone significant remodeling. The technique has been applied to archaeological shells and has returned dates that are younger than those previously determined for the same shells.

Impact of potassium fertilization and potassium uptake by plants on soil clay mineral assemblage in South Brazil

2016 ◽  
Vol 406 (1-2) ◽  
pp. 157-172 ◽  
Author(s):  
Diovane Freire Moterle ◽  
João Kaminski ◽  
Danilo dos Santos Rheinheimer ◽  
Laurent Caner ◽  
Edson Campanhola Bortoluzzi
Keyword(s):  
Clay Mineral ◽  
Mineral Assemblage ◽  
Potassium Uptake ◽  
Potassium Fertilization ◽  
Clay Mineral Assemblage ◽  
Soil Clay ◽  
South Brazil

scholarly journals Identification of heat-shock protein 90 beta in Japanese encephalitis virus-induced secretion proteins

2011 ◽  
Vol 92 (12) ◽  
pp. 2803-2809 ◽  
Author(s):  
Chun-Yu Hung ◽  
Meng-Chieh Tsai ◽  
Yi-Ping Wu ◽  
Robert Y. L. Wang
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Molecular Chaperones ◽  
Heat Shock Protein 90 ◽  
Rna Replication ◽  
Hsp90 Inhibitor ◽  
Encephalitis Virus ◽  
Virus Infectivity ◽  
Density Fractionation ◽  
Virus Particles

Five host cellular proteins were identified in the secretion medium from Japanese encephalitis virus (JEV)-infected baby hamster kidney-21 (BHK-21) cells, including three molecular chaperones: Hsp70, GRP78 and Hsp90. Hsp90 isoforms were characterized further. Hsp90α was observed to be retained inside the nuclei, whereas Hsp90β associated with virus particles during assembly and was released into the secretion medium upon JEV infection. The association of Hsp90β and viral E protein was demonstrated by using sucrose-density fractionation and Western blot analysis. Moreover, JEV viral RNA replication was not affected by treatment with geldanamycin, an Hsp90 inhibitor, but impaired virus infectivity that was determined by a plaque-forming assay. Our results show that Hsp90β, not Hsp90α, is present in the JEV-induced secretion medium and is required for JEV infectivity in BHK-21 cells.

The occurrence of gold in Voia deposit, South Apuseni Mountains, Romania

2021 ◽  
Author(s):  
Elena-Luisa Iatan
Keyword(s):  
Iron Oxides ◽  
Base Metal ◽  
Mineral Assemblage ◽  
Native Gold ◽  
Metal Sulfides ◽  
Volcanic Complex ◽  
Apuseni Mountains ◽  
Base Metal Sulfides ◽  
Mineral Assemblages ◽  
Phyllic Alteration

<p>Voia deposit belongs to the Săcărâmb-Cetraș-Cordurea Miocene volcano-tectonic alignment of the South Apuseni Mountains, Romania. This large volcanic complex represents a Sarmatian-Pannonian magmatic-hydrothemal mega-system of around 5 km<sup>2</sup> with an estimated 3–4 Ma time-space evolution, consisting of seven andesitic volcanic structures grouped in a circle, three subvolcanic andesite-quartz porphyry microdiorite and associated porphyry Cu-Au(Mo), pyrite Ca-Mg skarns and epithermal Au-Ag-Pb-Zn-Cu mineralizations.</p><p>The mineral assemblages of alteration and mineralization processes belong to several mineralized zones on a vertical scale, according to sampling evidence and laboratory studies. HS products are found in the upper part of the structure (300-500 m), with dominant advanced and intermediate argillic alterations and sulfide-sulfate gold-poor veins (pyrite, marcasite, base metal sulfides, Fe-Ti oxides, vuggy quartz, alunite, gypsum, anhydrite). Within the 500-1200 m depth, the HS mineral assemblages gradually decrease in favor of IS and LS products. It is characterized by the coexistence of gold-rich LS assemblage (native gold, base metal sulfide, adularia, sericite-illite, chlorite, carbonates ± anhydrite veins), with the IS assemblage (iron oxides, chalcopyrite, pyrite, quartz, anhydrite). These assemblages overprint the HS mineral associations, resulting in a transition zone characterized by gold - pyrite - chalcopyrite - iron oxides - quartz - anhydrite mineral assemblage characteristic for HS and native gold - pyrite - base metal sulfides - carbonates - quartz mineral assemblage corresponding to IS+LS type.</p><p>Gold is present in all of the identified mineralization forms: porphyry-epithermal Cu-Au, epi-mesothermal carbonate veins with gold - base metal sulfides, quartz veins with pyrite - chalcopyrite - magnetite ± hematite ± anhydrite, anhydrite veins with base metal sulfides and sulfosalts, anhydrite veins with pyrite - anhydrite ± quartz, vuggy quartz (silica residue) with gold-poor pyrite veins and impregnations in porphyry systems.</p><p>Drilling core samples revealed that in Voia deposit, gold is concentrated in chalcopyrite (drills no. 7, 19, 37) along with pyrite - magnetite - hematite - quartz assemblage from the late potassic stage. The major amount of gold associated with chalcopyrite tends to be mainly submicroscopic. Pyrite from anhydrite veins of the early potassic stage ± phyllic alteration is relatively poor in gold (drills no. 1-6, 8-14). However, the highest gold contents are present in pentagonal dodecahedron pyrites (drills no. 33, 38, 39) of pyrite-chalcopyrite-magnetite ± hematite-quartz assemblage from late potassic stage ± phyllic alteration. Pyrite associated with magnetite from anhydrite veins tends to be poor in gold (drills no. 8, 11, 15, 28, 29). A carbonate vein containing gold-bearing base metal sulfides that was intercepted at 960,00-960,30m depth by drill no. 17 is one of the richest in gold.</p><p>Native gold occurs as fine inclusions in ore minerals (5-20 μm). Large irregular grains of native gold (>50 μm) appear at mineral boundaries and along the fissures. The gold color is bright yellow and has a measured Au:Ag ratio of 5:1, suggesting that native gold has been formed at a relatively high temperature.</p><p>Acknowledgments: This work was supported by two Romanian Ministry of Research and Innovation grants: PN-III-P4-ID-PCCF-2016-4-0014 and PN-III-P1-1.2-PCCDI-2017-0346/29.</p>

scholarly journals Density fractions versus size separates: does physical fractionation isolate functional soil compartments?

2012 ◽  
Vol 9 (12) ◽  
pp. 5181-5197 ◽  
Author(s):  
C. Moni ◽  
D. Derrien ◽  
P.-J. Hatton ◽  
B. Zeller ◽  
M. Kleber
Keyword(s):  
Organic Matter ◽  
Mineral Soil ◽  
European Beech ◽  
Nitrogen Dynamics ◽  
Protective Mechanism ◽  
Density Fractionation ◽  
Adsorbed State ◽  
Density Fractions ◽  
Physical Fractionation ◽  
Comprehensive Picture

Abstract. Physical fractionation is a widely used methodology to study soil organic matter (SOM) dynamics, but concerns have been raised that the available fractionation methods do not well describe functional SOM pools. In this study we explore whether physical fractionation techniques isolate soil compartments in a meaningful and functionally relevant way for the investigation of litter-derived nitrogen dynamics at the decadal timescale. We do so by performing aggregate density fractionation (ADF) and particle size-density fractionation (PSDF) on mineral soil samples from two European beech forests a decade after application of 15N labelled litter. Both density and size-based fractionation methods suggested that litter-derived nitrogen became increasingly associated with the mineral phase as decomposition progressed, within aggregates and onto mineral surfaces. However, scientists investigating specific aspects of litter-derived nitrogen dynamics are pointed towards ADF when adsorption and aggregation processes are of interest, whereas PSDF is the superior tool to research the fate of particulate organic matter (POM). Some methodological caveats were observed mainly for the PSDF procedure, the most important one being that fine fractions isolated after sonication can not be linked to any defined decomposition pathway or protective mechanism. This also implies that historical assumptions about the "adsorbed" state of carbon associated with fine fractions need to be re-evaluated. Finally, this work demonstrates that establishing a comprehensive picture of whole soil OM dynamics requires a combination of both methodologies and we offer a suggestion for an efficient combination of the density and size-based approaches.

Phase equilibria in NaAlSiO4–KAlSiO4–SiO2–H2O at 100 MPa pressure: equilibrium leucite composition and the enigma of primary analcime in blairmorites revisited

2014 ◽  
Vol 78 (1) ◽  
pp. 171-202 ◽  
Author(s):  
C. M. B. Henderson ◽  
D. L. Hamilton ◽  
J. P. Waters
Keyword(s):  
Mineral Assemblage ◽  
Volcanic Rocks ◽  
Stoichiometric Composition ◽  
Pressure Equilibrium ◽  
Upward Transport ◽  
Higher Temperature ◽  
Invariant Points ◽  
Water Saturated ◽  
Low K ◽  
Maximum Content

AbstractExperiments in the system NaAlSiO4(Ne)−KAlSiO4(Ks)−SiO2(Qz)−H2O at 100 MPa show that the maximum content of NaAlSi2O6 in leucite is ∼4 wt.% and that analcime is close to the stoichiometric composition (NaAlSi2O6.H2O). Analcime forms metastably on quenching the higher-temperature experiments; it is secondary after leucite in experiments quenched from 780°C, while from 850°C it forms by alteration of leucite, and by devitrification of water-saturated glass. Both processes involve reaction with Na-rich aqueous fluids. Stable analcime forms at 500°C, well below the solidus, and cannot form as phenocrysts in shallow volcanic systems. New data for natural analcime macrocrysts in blairmorites are presented for the Crowsnest volcanics, Alberta, Canada. Other researchers have suggested that primary analcime occurs as yellow-brown, glassy, analcime phenocrysts. Our microprobe analyses show that such primary analcime is close to stoichiometric, with very low K2O (<0.1 wt.%), minor Fe2O3 (0.5−0.8 wt.%) and CaO (∼0.5 wt.%). An extrapolation of published experimental data for Ne−Ks−Qz at >500 MPa PH2O, where Anl + melt coexist, suggests that at >800 MPa two invariant points are present: (1) a reaction point involving Kf + Ab + Anl + melt + vapour; and (2) a eutectic with Kf + Anl + Ne + melt + vapour. We suggest that the nepheline-free equilibrium mineral assemblage for Crowsnest samples is controlled by reaction point (1). In contrast, blairmorites from Lupata Gorge, Mozambique, form at eutectic (2), consistent with the presence of nepheline phenocrysts. Our conclusions, based on high- vs. low-pressure experiments, confirm the suggestion made by other authors, that Crowsnest volcanic rocks must have been erupted explosively to preserve glassy analcime phenocrysts during very rapid, upward transport from deep in the crust (H2O pressures ≫500 MPa). Only rare examples survived the deuteric and hydrothermal alteration that occurred during and after eruption.

Roof modification of a high level granite, Jos-Bukuru Younger Granite Ring Complex, Nigeria

1974 ◽  
Vol 111 (1) ◽  
pp. 43-47 ◽  
Author(s):  
P. K. Webb
Keyword(s):  
Mineral Assemblage ◽  
Intrusive Body ◽  
Jos Plateau ◽  
Ring Complex ◽  
High Level

SummaryThe Rayfield-Gona granite of the Jos Plateau, Nigeria, formerly regarded as an independent intrusive body, is now thought to be a roof facies of the Ngell granite. This explains several phenomena, such as the gradational contact between the two, and the distinctive mineral assemblage of the former.

scholarly journals Petrology and genesis of the Bhainskati iron ore deposit of Palpa District, western Nepal

2013 ◽  
Vol 15 ◽  
pp. 63-68
Author(s):  
Sujan Devkota ◽  
Lalu Prasad Paudel
Keyword(s):  
Marine Environment ◽  
Mineral Assemblage ◽  
Iron Ore ◽  
Ore Deposit ◽  
Shallow Marine ◽  
Shallow Marine Environment ◽  
Long Time ◽  
Iron Ore Deposit ◽  
Petrographic Study ◽  
Oolitic Ironstone

The Bhainskati Formation of the Tansen Group in the Palpa area is known for hematite iron ore deposit for long time. A prominent band of hematite of about 1-2 m thickness and extending >5 km was identified in the upper part of the Bhainskati Formation in the present study. The band is repeated three times in the area by folding and faulting. Petrographic study shows that it is oolitic ironstone of sedimentary origin. Main minerals in the band are hematite, goethite, quartz, calcite, siderite and albite. Hematite content varies considerably among samples and occurs mainly as oolite and cement. The Bhainskati ironstone with its ferrous mineral assemblage and well-rounded texture of the ooids suggests shallow marine environment (prodeltaic to estuarine) with reduced clastic input. DOI: http://dx.doi.org/10.3126/bdg.v15i0.7418 Bulletin of the Department of Geology, Vol. 15, 2012, pp. 63-68

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