Iolite: Freeware for the visualisation and processing of mass spectrometric data

Paton, Chad; Hellström, John; Paul, Bence; Woodhead, Jon; Hergt, Janet

doi:10.1039/c1ja10172b

Cited by 3,139 publications

(1,366 citation statements)

References 13 publications

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“…Laser ablation conditions were as follows: ablation time of 60 s; fluence Bo3 J cm À 2 , repetition rate of 5 Hz; standard delay of 30 s for sample washout and background measurements; beam size of 55 mm. Raw data were reduced using the Iolite software package 64 . Isobaric interferences of 176 Yb and 176 Lu on 176 Hf were assessed and corrected following the procedure described by Woodhead et al 65 Plesovice zircon standard 66 was analysed to correct for instrumental drift, whereas Temora-2 and 91500 zircon references 67 Table 8).…”

Section: Methodsmentioning

confidence: 99%

Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?

et al. 2015

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Kimberlites and orangeites (previously named Group-II kimberlites) are small-volume igneous rocks occurring in diatremes, sills and dykes. They are the main hosts for diamonds and are of scientific importance because they contain fragments of entrained mantle and crustal rocks, thus providing key information about the subcontinental lithosphere. Orangeites are ultrapotassic, H 2 O and CO 2 -rich rocks hosting minerals such as phlogopite, olivine, calcite and apatite. The major, trace element and isotopic compositions of orangeites resemble those of intensely metasomatized mantle of the type represented by MARID (mica-amphibolerutile-ilmenite-diopside) xenoliths. Here we report new data for two MARID xenoliths from the Bultfontein kimberlite (Kimberley, South Africa) and we show that MARID-veined mantle has mineralogical (carbonate-apatite) and geochemical (Sr-Nd-Hf-O isotopes) characteristics compatible with orangeite melt generation from a MARID-rich source. This interpretation is supported by U-Pb zircon ages in MARID xenoliths from the Kimberley kimberlites, which confirm MARID rock formation before orangeite magmatism in the area.

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Section: Methodsmentioning

confidence: 99%

Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?

et al. 2015

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“…A total of 10 isotopes were determined ( 43 Ca, 44 Ca, 201 Hg, 202 Hg, 204 Pb, 206 Pb, 207 Pb, 208 Pb, 232 Th and 238 U). The dwell time on the Pb isotopes was 0.1 s with Ca isotopes measured for 0.03 s and Hg, U and Th measured for 0.0125 s. Laser induced U-Pb fractionation was accounted for during data reduction Paton et al, 2010;Paton et al, 2011). McClure Mountain syenite apatite (Thomson et al, 2012) was used as the primary standard as it has moderate but reasonably consistent U and Th contents (~23 ppm and 71 ppm; (Chew and Donelick, 2012) (Schoene and Bowring, 2006).…”

Section: U-pb Geochronologymentioning

confidence: 99%

“…For example, the mean 206 Pb/ 238 U age determined for Plešovice was 327 ± 10 Ma (2σ, n = 12, MSWD = 1.0), within uncertainty of the recommended value. The time-resolved mass spectra were reduced using the U/Pb Geochronology3 data reduction scheme in Iolite (Paton et al, 2011). No common lead corrections were deemed necessary due to low 204 Pb counts.…”

Section: U-pb Geochronologymentioning

confidence: 99%

“…In addition, fractionation of 207 Pb/ 206 Pb and 238 U/ 206 Pb was also monitored and corrected with reference to NIST 612, the advantage here over natural apatite being that the glass has a fixed common to radiogenic Pb ratio. Ages were derived for each time segment using Iolite 3.5 (Paton et al, 2011) with the VizualAge_UcomPbine DRS and in-house Microsoft Excel macros with 207 Pb corrections calculated as described above except common Pb was defined from the upper intercept of the spot analysis in the same sample (discussed in detail below). Excluding one aberrant step (step 3; 34 ± 1 Ma) 207 corrected ages for the Durango secondary reference reproduced the accepted age within analytical uncertainty (31.6 ± 0.7 Ma; MSWD 2.4).…”

Section: U-pb Geochronologymentioning

confidence: 99%

“…Secondary trace element standard NIST 612, treated as an unknown, reproduced recommended values to within 2% for all elements except P (5%). The time-resolved mass spectra were reduced using Iolite (Paton et al, 2011, and references therein). All analyses were sited on the centre of apatite grains where a single ablation pit could be located without touching the enclosing epoxy resin.…”

Section: U-pb Geochronologymentioning

confidence: 99%

See 2 more Smart Citations

Apatite: a U-Pb thermochronometer or geochronometer?

Kirkland

Yakymchuk

Szilas

et al. 2018

Lithos

122

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Apatite is an accessory mineral that is frequently found in both igneous and clastic sedimentary rocks. It is conventionally considered to be characterized by a closure temperature range between 375 and 600°C and hence has been employed to address mid-temperature thermochronology questions relevant to the reconstruction of thermal events in the middle to lower crust. However, questions remain as to whether apatite faithfully records thermally-activated volume diffusion profiles, or rather is influenced by recrystallization and new growth processes. We present a case study of two apatite samples from the Akia Terrane in Greenland that help chart some of the post magmatic history of this region. Apatite in a tonalitic gneiss has distinct U-enriched rims and its U-Pb apparent ages correlate with Mn chemistry, with a high Mn group yielding an age of c. 2813 Ma. The U-Pb and trace element chemistry and morphology support an interpretation in which these apatite crystals are originally igneous and record cooling after metamorphism, with subsequent generation of discrete new rims. Epidote observed in the sample implies a b600°C fluid infiltration event associated with apatite rims. The second sample, from a granitic leucosome, contains apparently homogeneous apatite, however U-Pb analyses define two distinct discordia arrays with different common Pb components. An older, c. 2490 Ma, component is associated with elevated Sr, whereas a younger, c. 1800 Ma, component has lower Sr concentration. A depth profile reveals an older core with progressively younger ages towards a compositionally discrete late Paleoproterozoic rim. The chemical and age profiles do not directly correspond, implying different diffusion rates between trace elements and U and Pb. The variation in core ages is interpreted to reflect radiogenic-Pb loss from a metamorphic population during new rim growth. The younger, c. 1800 Ma U-Pb age is interpreted to date new apatite growth from a compositionally distinct reservoir driven by tectonothermal and fluid activity, consistent with regional mica Ar-Ar ages. Results from these two samples show that recrystallization, dissolution and regrowth processes likely formed the younger rim overgrowths, and at temperatures below those often considered to be closure temperatures for Pb diffusion in apatite. The results from these samples imply many apatite grains may not record simple thermally activated Pb diffusion profiles and cautions against inversion of apatite U-Pb data to thermal histories without detailed knowledge of the grain growth/alteration processes.

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Simultaneous in situ determination of U‐Pb and Sm‐Nd isotopes in monazite by laser ablation ICP‐MS

Goudie

Fisher

Hanchar

et al. 2014

Geochem Geophys Geosyst

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Results are presented for in situ simultaneous determination of U-Pb and Sm-Nd isotopes in monazite using the Laser Ablation Split-Stream (LASS) method. This method uses a laser ablation system coupled to a magnetic-sector inductively coupled plasma mass spectrometer (HR) (ICP-MS) for measuring U-Pb isotopes and a multicollector (MC) ICP-MS for measuring Sm-Nd isotopes. Ablated material is split using a Y-connector and transported simultaneously to both mass spectrometers. In addition to Sm and Nd isotopes, the MC-ICP-MS is configured to also acquire Ce, Nd, Sm, Eu, and Gd elemental abundances. This approach provides age, tracer isotope, and trace element data in the same ablation volume, reducing sampling problems associated with fine-scale zoning in accessory minerals and minimizing the material needed for ablation. Precision and accuracy of the U-Pb method (and the precision of the Sm-Nd method) is demonstrated with results from well-characterized monazite reference materials. The LASS results agree within uncertainty with the isotope dilution thermal ionization mass spectrometry (ID-TIMS) U-Pb dates. The accuracy of the Sm-Nd method is assessed by comparing the LA-MC-ICP-MS results with ID-TIMS determinations on a well-characterized, in-house monazite reference material. The LASS method is then applied to monazite from the Birch Creek Pluton in the White Mountains of California as a case study to illustrate the utility of this method for solving geologic problems. The U-Pb ages and Sm-Nd isotopic data from the LASS method support the conclusions drawn from previous results that monazite can record timing and information about the source region(s) of hydrothermal fluids.

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Iolite: Freeware for the visualisation and processing of mass spectrometric data

Cited by 3,139 publications

References 13 publications

Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?

Did diamond-bearing orangeites originate from MARID-veined peridotites in the lithospheric mantle?

Apatite: a U-Pb thermochronometer or geochronometer?

Simultaneous in situ determination of U‐Pb and Sm‐Nd isotopes in monazite by laser ablation ICP‐MS

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