Coupling thermodynamic modeling and high-resolution in situ LA-ICP-MS monazite geochronology: evidence for Barrovian metamorphism late in the Grenvillian history of southeastern Ontario

2014 ◽  
Vol 108 (6) ◽  
pp. 741-758 ◽  
Author(s):  
Travis McCarron ◽  
Fred Gaidies ◽  
Christopher R. M. McFarlane ◽  
R. Michael Easton ◽  
Peter Jones
Keyword(s):  
High Resolution ◽  
Thermodynamic Modeling ◽  
Icp Ms ◽  
History Of

In situ determination of precise stable Si isotope ratios by UV-femtosecond laser ablation high-resolution multi-collector ICP-MS

2008 ◽  
Vol 249 (1-2) ◽  
pp. 155-166 ◽  
Author(s):  
Jérôme Chmeleff ◽  
Ingo Horn ◽  
Grit Steinhoefel ◽  
Friedhelm von Blanckenburg
Keyword(s):  
Laser Ablation ◽  
High Resolution ◽  
Femtosecond Laser ◽  
Femtosecond Laser Ablation ◽  
Isotope Ratios ◽  
Icp Ms ◽  
Si Isotope

First in-situ Rb-Sr dating of metasedimentary rocks from the Pontiac subprovince, Superior Craton, Canada. Implications towards the regional metamorphic evolution of the sequence.

2020 ◽  
Author(s):  
Nicholas Leventis ◽  
Thomas Zack ◽  
Iain Pitcairn ◽  
Johan Högmalm
Keyword(s):  
Accretionary Prism ◽  
Metasedimentary Rocks ◽  
Metamorphic History ◽  
Accuracy And Precision ◽  
Icp Ms ◽  
Age Variations ◽  
History Of ◽  
Peak Metamorphism ◽  
Superior Craton

<p>The Pontiac subprovince consists of metaturbidites, plutons and thin ultramafic rock layers of Archean age and lies south of the Cadillac-Larder Lake (C-LL) fault zone which is the boundary between the Pontiac and the extensively mineralized Abitibi Greenstone Belt. The sediments show a Barrovian metamorphic gradient which increases southwards, away from the C-LL fault. The most likely tectonic provenance for the Pontiac sedimentary rocks is that they represent a relic accretionary prism with material derived from both the Abitibi and an older terrane. Zircon U-Pb dating shows that deposition occurred not later than 2685±3 Ma ago and recent, robust Lu-Hf dating of garnets bracketed Pontiac's peak metamorphic conditions at 2658±4 Ma. For this study we used a recently developed LA-ICP-MS/MS method for in-situ Rb-Sr dating of biotite and plagioclase in samples ranging in metamorphic grade (biotite to sillimanite zones) from the Pontiac subprovince. Calibration of the instrument was achieved by repeated ablations on several reference materials (see Hogmalm et al. 2017) which also provided the monitoring of accuracy and precision throughout the analyses. Results show a range in dates between 2550 Ma and 2200 Ma with an average of 2440±50 Ma (2σ). Samples from the staurolite and kyanite zones have a larger range with respect to the other zones, but no significant differences are observed in the data with any method of data handing. These dates are ≈300Ma younger than the peak metamorphism in the area and this is attributed to either overgrowth and re-setting of the Rb-Sr system by a second metamorphic/hydrothermal event, or diffusional resetting with core-rim age variations. Possible influence from the adjacent late syntectonic to post-tectonic monzodiorite-monzonite-granodiorite-syenite (MMGS) plutons dated 2671±4 Ma and the garnet-muscovite-granite series (GMG) dated ≈2650 Ma cannot be ruled out. This study provides insights about the metamorphic history of the sequence and supports previous findings regarding resetting of some isotopic systems with relatively low closure temperatures (≈350-400°C) by later thermal events.</p>

scholarly journals LA-ICP-MS U–Pb Dating of Cenozoic Rutile Inclusions in the Yuanjiang Marble-Hosted Ruby Deposit, Ailao Shan Complex, Southwest China

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 433
Author(s):  
Tianjian Yang ◽  
Xiaoming Sun ◽  
Guiyong Shi ◽  
Ying Liu
Keyword(s):  
Southwest China ◽  
Mineral Deposits ◽  
Cooling History ◽  
Host Matrix ◽  
Icp Ms ◽  
Lateral Shearing ◽  
The World ◽  
History Of ◽  
Tectonic Belt

Among the marble-hosted ruby deposits in the Himalayan tectonic belt, which yields the highest-quality rubies in the world, the Yuanjiang deposit is the only economically viable one located in China. More attempts are necessary to put constraints on the ore-forming age of these marble-hosted ruby deposits. Here, we dated rutile inclusions in the Yuanjiang rubies using the LA-ICP-MS U–Pb method, which yielded a lower intercept 206Pb/238U age of 20.2 ± 1.2 Ma on the Tera-Wasserburg plot, close to the 22.5–22.2 Ma 40Ar/39Ar ages of phlogopite from the ruby host matrix assemblage. Our U–Pb rutile age put a constraint on the cooling history of the Yuanjiang rubies deposit. The new rutile age is consistent with our previous model that shows the ca. 28–22 Ma left lateral shearing plays an important role in transporting the ruby deposit toward the surface. This study provides the first example of in-situ U–Pb dating of rutile in the Himalayan tectonic belt, demonstrating the great potential of U–Pb rutile geochronology for Cenozoic mineral deposits.

scholarly journals Towards <i>in-situ</i> U–Pb dating of dolomites

2020 ◽  
Author(s):  
Bar Elisha ◽  
Perach Nuriel ◽  
Andrew Kylander-Clark ◽  
Ram Weinberger
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Dolomitic Rock ◽  
Icp Ms ◽  
Highly Sensitive ◽  
Wide Range ◽  
Absolute Dating ◽  
Crater Morphology ◽  
Epigenetic Processes

Abstract. Recent U–Pb dating by laser ablation ICP-MS has demonstrated that reasonable precision (3–10 % 2σ) can be achieved for high-resolution dating of texturally distinct calcite phases. Absolute dating of dolomite, for which biostratigraphy and traditional dating techniques are very limited, remains challenging but may resolve many fundamental questions related to the timing of mineral-rock formation by syngenetic, diagenesis, hydrothermal, and epigenetic processes. In this study we explore the possibility of dating dolomitic rocks via recent LA-ICP-MS dating techniques developed for calcite. The in-situ U–Pb dating was tested on a wide range of dolomite rocks of various origins (i.e., syngenetic, early diagenetic and epigenetic) from the Cambrian to Pliocene age – all of which from well-constrained stratigraphic sections in Israel. We present in-situ U–Pb results of dolomitic rock samples, together with imaging techniques and chemical characterizations. We show that dolomite dating is highly sensitive to textural differences and highlight parameters such as crater morphology and roughness, calcite zoning and impurities that may affect the interpretation of the resulted ages. Textural examination indicates zonation and mixing of different phases at the sub-millimeter scale (

scholarly journals DETERMINANDO A DURAÇÃO DO PERÍODO COLISIONAL DO ORÓGENO ARAÇUAÍ COM BASE EM GEOCRONOLOGIA U-PB DE ALTA RESOLUÇÃO EM ZIRCÃO: UMA CONTRIBUIÇÃO PARA A HISTÓRIA DA AMALGAMAÇÃO DO GONDWANA OCIDENTAL

2013 ◽  
Author(s):  
Luiz Carlos Da Silva ◽  
Antônio Carlos Pedrosa-Soares ◽  
Richard Armstrong ◽  
Carlos Maurício Noce
Keyword(s):  
High Resolution ◽  
Gravitational Collapse ◽  
Analytical Data ◽  
Time Limits ◽  
West Gondwana ◽  
Icp Ms ◽  
History Of ◽  
Lateral Escape ◽  
Araçuaí Orogen

O presente artigo rastreia efeitos ígneos e metamórficos da colisão entre a Península do São Francisco e o Cráton do Congo, durante a amalgamação do Gondwana Ocidental, por meio de análises geocronológicas U-Pb de alta resolução (SHRIMP e LA-ICP-MS) em zircão, com apoio de imagens de catodo-luminescência (CL). Os dados obtidos em oito amostras, cotejados com uma vasta compilação bibliográfica, limitam o estágio sincolisional do Orógeno Araçuaí em ca. 585-560 Ma, provavelmente contemporâneo do mesmo processo no Orógeno Ribeira Setentrional. Estes limites de tempo são revelados tanto por idades de cristalização magmática sin-deformacional, quanto pelo metamorfismo regional de médio a alto grau em unidades supracrustais e infracrustais. Desta forma, a amalgamação da Península do São Francisco com o Cráton do Congo, representada pela cicatriz orogênica Araçuaí-Ribeira Setentrional, teve sua fase terminal em torno de 560 Ma. A partir desta época, a tectônica compressiva tangencial, de abrangência regional, passou a dar lugar a escapes laterais e zonas de colapso gravitacional, aos quais se associaram episódios térmicos que causaram recristalização relativamente discreta e/ou localizada nas rochas regionais, mas detectáveis em análises U-Pb e imageamento CL de zircão, e geraram uma miríade de manifestações ígneo-anatéticas tardi- a pós-colisionais.Palavras-chave: geocronologia U-Pb, zircão, colisão, Orógeno Araçuaí, Gondwana ABSTRACT: DETERMINING THE TIMING OF THE COLLISIONAL PERIOD OF THE ARAÇUAÍ OROGEN BY USING HIGH RESOLUTION U-Pb GEOCHRONOLOGY ON ZIRCON: A CONTRIBUTION TO THE HISTORY OF WESTERN GONDWANA AMALGAMATION. This paper tracks igneous and metamorphic effects of the collision between the São Francisco peninsula and Congo craton, during the amalgamation of Western Gondwanaland, based on high resolution (SHRIMP and LA-ICP-MS) U-Pb zircon analysis, coupled with studies on cathodoluminescence (CL) images. Analytical data obtained from eight samples, compared with a large number of data compiled from the literature, constrain the syn-collisional stage of the Araçuaí orogen from ca. 585 Ma to ca. 560 Ma, probably coeval with the same process in the Northern Ribeira orogen. These time limits are revealed by ages from both magmatic crystallization and metamorphic overprinting on distinct rocks from different units. Therefore, the amalgamation of the São Francisco peninsula and Congo craton, represented by the Araçuaí- Northern Ribeira orogenic scar, was already accomplished around 560 Ma. After this epoch, the regional compressive (tangential) tectonics gave place to lateral escape and gravitational collapse zones, associated with thermal episodes that caused relatively discrete and/or local recrystallization on the country rocks, but detectable by U-Pb analysis and CL imagery on zircon, and generated a myriad of late to post-collisional igneous-anatectic manifestations.Keywords: U-Pb geochronology, zircon, collision, Araçuaí orogen, West Gondwana

scholarly journals Zinc and Cadmium Mapping in the Apical Shoot and Hypocotyl Tissues of Radish by High-Resolution Secondary Ion Mass Spectrometry (NanoSIMS) after Short-Term Exposure to Metal Contamination

2019 ◽  
Vol 16 (3) ◽  
pp. 373 ◽  
Author(s):  
Gabrijel Ondrasek ◽  
Peta Clode ◽  
Matt Kilburn ◽  
Paul Guagliardo ◽  
Davor Romić ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Secondary Ion Mass Spectrometry ◽  
Short Term ◽  
Fast Growing ◽  
Icp Ms ◽  
Short Term Exposure ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Zinc (as an essential phytonutrient) and cadmium (as a toxic but readily bioavailable nonessential metal for plants) share similar routes for crossing plant biomembranes, although with a substantially different potential for translocation into above-ground tissues. The in situ distribution of these metals in plant cells and tissues (particularly intensively-dividing and fast-growing areas) is poorly understood. In this study, 17-day-old radish (Raphanus sativus L.) plants grown in nutrient solution were subjected to short-term (24 h) equimolar contamination (2.2 µM of each 70Zn and Cd) to investigate their accumulation and distribution in the shoot apex (leaf primordia) and edible fleshy hypocotyl tissues. After 24-h exposure, radish hypocotyl had similar concentration (in µg/g dry weight) of 70Zn (12.1 ± 1.1) and total Cd (12.9 ± 0.8), with relatively limited translocation of both metals to shoots (concentrations lower by 2.5-fold for 70Zn and 4.8-fold for Cd) as determined by inductively-coupled plasma mass spectrometry (ICP-MS). The in situ Zn/Cd distribution maps created by high-resolution secondary ion mass spectrometry (NanoSIMS, Cameca, Gennevilliers, France) imaging corresponded well with the ICP-MS data, confirming a similar pattern and uniform distribution of 70Zn and Cd across the examined areas. Both applied techniques can be powerful tools for quantification (ICP-MS) and localisation and visualisation (NanoSIMS) of some ultra-trace isotopes in the intensively-dividing cells and fast-growing tissues of non-metalophytes even after short-term metal exposure. The results emphasise the importance of the quality of (agro)ecosystem resources (growing media, metal-contaminated soils/waters) in the public health risk, given that, even under low contamination and short-term exposure, some of the most toxic metallic ions (e.g., Cd) can relatively rapidly enter the human food chain.

mRNA localization by Electron microscopic in situ hybridization

1991 ◽  
Vol 49 ◽  
pp. 430-431
Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Nucleic Acids ◽  
Recombinant Dna ◽  
Light And Electron Microscopy ◽  
Electron Microscopic ◽  
High Voltage Electron Microscopy ◽  
Functional Sites ◽  
Voltage Electron

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.

Ultrastructural analysis of the spatial distribution of MRNA

1992 ◽  
Vol 50 (1) ◽  
pp. 552-553
Author(s):  
Gary Bassell ◽  
Robert H. Singer
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
In Situ Hybridization ◽  
High Resolution ◽  
Nucleic Acids ◽  
Colloidal Gold ◽  
Dna Probe ◽  
Nucleotide Analogs ◽  
Gold Particles

We have been investigating the spatial distribution of nucleic acids intracellularly using in situ hybridization. The use of non-isotopic nucleotide analogs incorporated into the DNA probe allows the detection of the probe at its site of hybridization within the cell. This approach therefore is compatible with the high resolution available by electron microscopy. Biotinated or digoxigenated probe can be detected by antibodies conjugated to colloidal gold. Because mRNA serves as a template for the probe fragments, the colloidal gold particles are detected as arrays which allow it to be unequivocally distinguished from background.

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