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

McCarron, Travis; Gaidies, Fred; McFarlane, Christopher R.M.; Easton, R.M.; Jones, Peter Tom

doi:10.1007/s00710-014-0343-5

Cited by 11 publications

(18 citation statements)

References 40 publications

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“…U-Pb monazite and zircon ages of 1020 AE 3 Ma of sillimanite-zone Flinton Group rocks have been interpreted to reflect the timing of peak metamorphism during the Ottawan phase (Corfu & Easton, 1995). This conflicts with in situ LA-ICP-MS U-Pb ages of c. 976 AE 4 Ma obtained for monazite inclusions in garnet rims and matrix monazite in a staurolitezone mica schist from the Flinton Group (McCarron et al, 2014). These monazite ages are similar to the age of a pegmatite (c. 984 AE 4 Ma) that crosscuts the sillimanitezone mica schists and is interpreted to mark a period of hydrothermal activity late in the metamorphic history of the Grenville Orogeny (Corfu & Easton, 1995).…”

Section: Regional Geologymentioning

confidence: 75%

Polymetamorphism during the Grenvillian Orogeny in SE Ontario: Results from trace element mapping, in situ geochronology, and diffusion geospeedometry

Gaidies,

Mccarron,

Simpson

et al. 2023

Journal Metamorphic Geology

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The Flinton Group is a metasedimentary succession of the Grenville Province in SE Ontario, potentially allowing insight into the tectono‐thermal evolution of continental crust during the Mesoproterozoic. At its Green Bay locality, Flinton Group metapelites of the staurolite zone contain abundant, post‐kinematic garnet porphyroblasts. Whereas the larger garnet crystals are typically impinged, smaller crystals are isolated from each other, occasionally exhibiting elongated shapes with apparently trigonal morphology. Central sections of the garnet population of a representative sample reveal that garnet is composed of different compositional and microstructural domains. In the largest crystals of the population, garnet contains rectangular to rhombic domains, marked by sharp increases in the concentrations of Nb, V, Ti, and Cr. These domains are associated with irregularly shaped patches, characterized by spatially heterogenous enrichments of Ca and LREE, and depletions in the contents of P, Y, MREE, and HREE, accompanied by increased densities of comparatively coarse‐grained quartz inclusions hosting apatite. Microstructural relationships indicate that these domains correspond to portions of garnet that pseudomorphed biotite, with the enrichments of Nb, V, Ti, and Cr outlining the original biotite shapes. The compositional patterns formed by Ca, P, Y, and REE indicate that apatite participated in the grain‐fluid interactions that operated during the metasomatic replacement of biotite by garnet. The statistical analyses of the garnet number and size distributions confirm that garnet initially nucleated on biotite, controlled by the kinetics of attachment and detachment processes at the garnet/biotite interface, resulting in the typical impingement habit. In situ Lu–Hf garnet geochronology applied to garnet that did not pseudomorph biotite, and hence is enriched in HREE, points to a first metamorphic event at c. 1080 31 Ma. Subsequent pseudomorphism of staurolite by white mica in a Al2O3‐ and FeO‐mobile system resulted in the concomitant crystallization of a new garnet generation, forming overgrowths on the first garnet generation and nuclei in the fine‐grained matrix. Garnet that nucleated during this event grew to isolated and elongated crystals with apparently trigonal morphology, aligned in a direction c. perpendicular to the rock matrix foliation. The open‐system behaviour during this event limits the use of whole‐rock‐based geochronological and thermobarometrical applications. However, previously published in situ U–Pb ages of monazite included in the rims of the garnet crystals and in the rock matrix indicate that this event took place at c. 976 4 Ma, likely associated with a period of increased hydrothermal activity late in the metamorphic history of the Grenvillian Orogeny. Diffusion geospeedometry calculations indicate that garnet growth during this hydrothermal event lasted for less than 6 Myr.

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Section: Regional Geologymentioning

confidence: 75%

Polymetamorphism during the Grenvillian Orogeny in SE Ontario: Results from trace element mapping, in situ geochronology, and diffusion geospeedometry

Gaidies,

Mccarron,

Simpson

et al. 2023

Journal Metamorphic Geology

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“…Semi‐quantitative or qualitative approaches in LA‐ICP‐MS mapping are often based on the raw signal and reported in terms of raw counts per second (McCarron et al . 2014, Ubide et al . 2015, Cook et al .…”

Section: Resultsmentioning

confidence: 99%

A New Mapping Protocol for Laser Ablation (withFast‐Funnel) Coupled to aTime‐of‐FlightMass Spectrometer (LA‐FF‐ICP‐ToF‐MS) for the Rapid, Simultaneous Quantification of Multiple Minerals

Savard

Dare

Bèdard

et al. 2023

Geostandard Geoanalytic Res

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Although in situ analysis by LA-ICP-MS is considered a rapid technique with minimal sample preparation and data reduction, mapping areas of millimetres in size using a small beam (< 15 μm) can be time consuming (several hours) when a quadrupole ICP-MS is used. In addition, fully quantitative imaging using internal standardisation by LA-ICP-MS is challenging in samples with more than one mineral phase present due to varying ablation rates. A new protocol for the quantification of multiple coexisting phases, mapped at a rate of about 12 mm 2 h -1 and a resolution of 12 μm × 12 μm per pixel, is presented. The protocol allows mapping of most atomic masses, ranging from 23 Na to 238 U, using a time-offlight mass spectrometer (ICP-ToF-MS, TOFWERK) connected to a 193 nm excimer laser. A fast-funnel device was successfully used to increase the aerosol transport speed, reducing the time usually required for mapping by a factor of about ten compared with a quadrupole ICP-MS. The lower limits of detection for mid and heavy masses are in the range 0.1-10 μg g -1 , allowing determination of trace to ultra-trace elements. The presented protocol is intended to be a routine analytical tool that can provide greater access to the spatial distribution of major and trace elements in geological materials.

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“…The first applications of LA-ICPMS imaging in the early 1990s were mainly focused on the study of element distributions in geological materials. − The scope of applications for LA-ICPMS mapping in geology was gradually extended, − to include key applications in geochronology. , At a later stage, the technique was adopted by archaeometry − and biochemistry. − The lateral resolution of LA-ICPMS (∼5–>50 μm) falls short of that achievable in nano X-ray fluorescence spectroscopy and nano secondary ion mass spectrometry, which boast resolutions in the order of 100 nm and below, while limits of detection of these techniques are comparable (ppm-ppb range). A large number of applications and studies, including metallomics, zircon geochronology, , multiplexed diagnostic analysis of biological tissues, and trace element migration pattern imaging, could benefit from higher spatial resolution in LA-ICPMS imaging, due to the relevance of the spatial distribution of nuclides at the (sub-)micrometer scale level, and considering the limited accessibility to competitive nanoscale techniques. Lateral resolution in LA-ICPMS imaging procedures is governed by the laser beam waist size projected onto the sample and a combination of the degree of overlap of the asymmetric pulse response peaks, bidirectional stage velocity, precision and repeatability, sampling approach and conditions, and mass analyzer dwell and settling timings.…”

mentioning

confidence: 99%

Submicrometer Imaging by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry via Signal and Image Deconvolution Approaches

2015

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In this work, pre- and postacquisition procedures for enhancing the lateral resolution of laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) in two- and three-dimensional (2D, 3D) nuclide distribution mapping beyond the laser beam waist are described. 2D images were constructed by projecting a rectangular grid of discrete LA positions, arranged at interspacings smaller than the dimensions of the laser beam waist, onto the sample surface, thus oversampling the region of interest and producing a 2D image convolved in the spatial domain. The pulse response peaks of a low-dispersion LA cell were isolated via signal deconvolution of the transient mass analyzer response. A 3D stack of 2D images was deconvolved by an iterative Richardson-Lucy algorithm with Total Variance regularization, enabling submicrometer image fidelity, demonstrated in the analysis of trace level features in corroded glass. A point spread function (PSF) could be derived from topography maps of single pulse craters from atomic force microscopy. This experimental PSF allows the approach to take into account the laser beam shape, beam aberrations, and the laser-solid interaction, which in turn enhances the spatial resolution of the reconstructed volume.

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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

Cited by 11 publications

References 40 publications

Polymetamorphism during the Grenvillian Orogeny in SE Ontario: Results from trace element mapping, in situ geochronology, and diffusion geospeedometry

Polymetamorphism during the Grenvillian Orogeny in SE Ontario: Results from trace element mapping, in situ geochronology, and diffusion geospeedometry

A New Mapping Protocol for Laser Ablation (withFast‐Funnel) Coupled to aTime‐of‐FlightMass Spectrometer (LA‐FF‐ICP‐ToF‐MS) for the Rapid, Simultaneous Quantification of Multiple Minerals

Submicrometer Imaging by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry via Signal and Image Deconvolution Approaches

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