The effect of grain orientation on secondary ion mass spectrometry (SIMS) analysis of rutile

Taylor, R. C.; Clark, Chris; Reddy, Steven M.

doi:10.1016/j.chemgeo.2012.01.013

Cited by 51 publications

(41 citation statements)

References 23 publications

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“…U and Th contents calculated from SHRIMP analyses are therefore only accurate to within a factor of two. We did not observe a stable, reproducible peak at ~192 AMU as used by Taylor et al (2012) for a reference. Data were processed with SQUID 1.13a (Ludwig 2001) using the same ln(Pb*/U)/ln(UO/U) calibration as for zircon (e.g.…”

Section: Methodsmentioning

confidence: 54%

“…Williams 1998). Because of the higher count rates on UO and UO 2 relative to U, some previous SHRIMP studies have used alternative calibrations for rutile: ln(Pb*/ UO)-ln(U/UO) (Clark et al 2000) and ln(Pb/U)-ln(UO 2 / UO) (Taylor et al 2012). However, in our sessions, the traditional ln(Pb*/U)/ln(UO/U) calibration performed at least as well as alternative calibrations for rutile, and sometimes better.…”

Section: Methodsmentioning

confidence: 99%

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Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

Ewing

Rubatto

Beltrando

et al. 2015

Contrib Mineral Petrol

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documented along the western margin of the Adriatic plate. The ~160 Ma age population postdates the activity of all known rift-related structures within the Adriatic margin, but coincides with extensive gabbroic magmatism and exhumation of sub-continental mantle to the floor of the Alpine Tethys, west of the Ivrea Zone. We propose that this ~160 Ma early post-rift age population records regional cooling following episodic heating of the distal Adriatic margin, likely related to extreme lithospheric thinning and associated advection of the asthenosphere to shallow levels. The partial preservation of the ~175 Ma age cluster suggests that the post-rift (~160 Ma) heating pulse was of short duration. The regional consistency of the data presented here, which is in contrast to many other thermochronometers in the IVZ, demonstrates the value of the rutile U-Pb technique for probing the thermal evolution of high-grade metamorphic terrains. In the IVZ, a significant decoupling between Zr-in-rutile temperatures and U-Pb ages of rutile is observed, with the two systems recording events ~120 Ma apart.

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Section: Methodsmentioning

confidence: 54%

Section: Methodsmentioning

confidence: 99%

Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

Ewing

Rubatto

Beltrando

et al. 2015

Contrib Mineral Petrol

View full text Add to dashboard Cite

show abstract

“…EBSD has also proven most helpful in examining potential variation in isotopic signature with crystal orientation of iron-oxides [72], rutile [73], or cassiterite [74]. Because electron backscatter patterns are generated from the uppermost few tens of nanometres of the sample surface, preparation and chemical polishing routines need to be optimised.…”

Section: Electron Back-scatter Diffraction (Ebsd)mentioning

confidence: 99%

Advances and Opportunities in Ore Mineralogy

et al. 2017

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Abstract:The study of ore minerals is rapidly transforming due to an explosion of new microand nano-analytical technologies. These advanced microbeam techniques can expose the physical and chemical character of ore minerals at ever-better spatial resolution and analytical precision. The insights that can be obtained from ten of today's most important, or emerging, techniques and methodologies are reviewed: laser-ablation inductively-coupled plasma mass spectrometry; focussed ion beam-scanning electron microscopy; high-angle annular dark field scanning transmission electron microscopy; electron back-scatter diffraction; synchrotron X-ray fluorescence mapping; automated mineral analysis (Quantitative Evaluation of Mineralogy via Scanning Electron Microscopy and Mineral Liberation Analysis); nanoscale secondary ion mass spectrometry; atom probe tomography; radioisotope geochronology using ore minerals; and, non-traditional stable isotopes. Many of these technical advances cut across conceptual boundaries between mineralogy and geochemistry and require an in-depth knowledge of the material that is being analysed. These technological advances are accompanied by changing approaches to ore mineralogy: the increased focus on trace element distributions; the challenges offered by nanoscale characterisation; and the recognition of the critical petrogenetic information in gangue minerals, and, thus the need to for a holistic approach to the characterization of mineral assemblages. Using original examples, with an emphasis on iron oxide-copper-gold deposits, we show how increased analytical capabilities, particularly imaging and chemical mapping at the nanoscale, offer the potential to resolve outstanding questions in ore mineralogy. Broad regional or deposit-scale genetic models can be validated or refuted by careful analysis at the smallest scales of observation. As the volume of information at different scales of observation expands, the level of complexity that is revealed will increase, in turn generating additional research questions. Topics that are likely to be a focus of breakthrough research over the coming decades include, understanding atomic-scale distributions of metals and the role of nanoparticles, as well how minerals adapt, at the lattice-scale, to changing physicochemical conditions. Most importantly, the complementary use of advanced microbeam techniques allows for information of different types and levels of quantification on the same materials to be correlated.

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“…Secondly, it requires corrections for bulk composition for zircons with more than 2000 ppm U (Williams and Hergt, 2000;White and Ireland, 2012), or for minerals that exhibit complex solid solution, such as monazite (Gregory et al, 2007;Fletcher et al, 2010). Thirdly, some simple oxides, such as baddeleyite and rutile, exhibit orientation-related deviations from the calibration (Wingate and Compston, 2000;Schmitt et al, 2010;Taylor et al, 2012).…”

Section: W Magee Jr Et Al: Isotopologue Disequilibrium In Simsmentioning

confidence: 99%

Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology

Magee

Danišík

Mernagh

2017

Geosci. Instrum. Method. Data Syst.

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Abstract. The current limitation in the accuracy and precision of inter-element analysis in secondary ion mass spectrometry (SIMS) is the ability to find measurable quantities that allow relative differences in ionization and transmission efficiency of secondary ions to be normalized. In uraniumthorium-lead geochronology, the ability to make these corrections, or "calibrate" the data, results in an accuracy limit of approximately 1 %. This study looks at the ionization of uranium and thorium oxide species, which are traditionally used in U-Pb calibration, to explore the conditions under which isotopologues, or molecular species whose composition differs only in the isotopic composition of one or more atoms in the molecule, remain in or deviate from equilibrium.Isotopologue deficits of up to 0.2 (200 ‰) below ideal mixing are observed in UO + 2 species during SIMS gechronological analyses using the SHRIMP IIe SIMS instrument. These are identified by bombarding natural U-bearing minerals with an 18 O − 2 primary beam. The large anomalies are associated with repeat analyses down a single SIMS sputtering crater (Compston et al., 1984), analysis of high-uranium, radiation-damaged zircon, and analysis of baddeleyite. Analysis of zircon under routine conditions yield UO + 2 isotopologue anomalies generally within a few percent of equilibrium. The conditions under which the isotopologue anomalies are observed are also conditions in which the UO x -based corrections, or calibration, for relative U vs. Pb ionization efficiencies fail. The existence of these isotopologue anomalies suggest that failure of the various UO x species to equilibrate with each other is the reason that none of them will successfully correct the U / Pb ratio. No simple isotopologuebased correction is apparent. However, isotopologue disequilibrium appears to be a more sensitive tool for detecting high-U calibration breakdowns than Raman spectroscopy, which showed sharper peaks for ∼ 37 Ma high-uranium zircons than for reference zircons OG1 and Temora. U-ThSm / He ages were determined for aliquots of reference zircons OG1 (755±71 Ma) and Temora (323±43 Ma), suggesting that the broader Raman lines for the Temora reference zircons may be due to something other than accumulated radiation damage.Isotopologue abundances for UO + and ThO + and their energy spectra are consistent with most or all molecular species being the product of atomic recombination when the primary beam impact energy is greater than 5.7 keV. This, in addition to the large UO + 2 instrumentally generated isotopologue disequilibria, suggests that any attempts to use SIMS to detect naturally occurring isotopologue deviations could be tricky.

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The effect of grain orientation on secondary ion mass spectrometry (SIMS) analysis of rutile

Cited by 51 publications

References 23 publications

Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

Constraints on the thermal evolution of the Adriatic margin during Jurassic continental break-up: U–Pb dating of rutile from the Ivrea–Verbano Zone, Italy

Advances and Opportunities in Ore Mineralogy

Extreme isotopologue disequilibrium in molecular SIMS species during SHRIMP geochronology

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