Zircon Hf-isotope analysis with an excimer laser, depth profiling, ablation of complex geometries, and concomitant age estimation

Woodhead, Jon; Hergt, Janet; Shelley, Michael; Eggins, Stephen; Kemp, Roger

doi:10.1016/j.chemgeo.2004.04.026

Cited by 833 publications

(338 citation statements)

References 27 publications

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“…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). On the basis of the results for standards (this session and long term), analytical reproducibility (external precision) for 176 Hf/ 177 Hf is B ± 0.000050 (2 s.d.…”

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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“…Isobaric interferences of Yb and Lu on the 176 peak were corrected for using a dual approach, firstly by doping solution standards to determine 176 Yb/ 173 Yb (Thirlwall & Walder, 1995), and secondly by determining Yb mass bias in situ during ablation (Woodhead et al 2004). In the first approach, a Yb solution was mixed with the JMC 475 Hf solution standard to achieve a range of Yb/Hf ratios (0.02, 0.07 and 0.1) in order to determine an empirical vale for the 176 Yb/ 173 Yb ratio.…”

Section: Methodsmentioning

confidence: 99%

Hidden Archaean and Palaeoproterozoic crust in NW Ireland? Evidence from zircon Hf isotopic data from granitoid intrusions

et al. 2009

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-The presence of major crystalline basement provinces at depth in NW Ireland is inferred from in situ Hf isotope analysis of zircons from granitoid rocks that cut structurally overlying metasedimentary rocks. Granitoids in two of these units, the Slishwood Division and the Tyrone Central Inlier, contain complex zircons with core and rim structures. In both cases, cores have average εHf values that differ from the average εHf values of the rims at 470 Ma (the time of granitoid intrusion). The Hf data and similarity in U-Pb age between the inherited cores and detrital zircons from the host metasedimentary rocks suggests local contamination during intrusion rather than transport of the grains from the source region at depth. Rims from the Slishwood Division intrusions have average εHf 470 values of −7.7, consistent with a derivation from juvenile Palaeoproterozoic crust, such as the Annagh Gneiss Complex or Rhinns Complex of NW Ireland, implying that the deep crust underlying the Slishwood Division is made of similar material. Rims from the Tyrone Central Inlier have extremely negative εHf 470 values of approximately −39. This isotopic signature requires an Archaean source, suggesting rocks similar to the Lewisian Complex of Scotland, or sediment derived wholly from it, occurs at depth in NW Ireland.

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“…Spot sizes of 40 lm with a laser repetition rate of 8 Hz at 100 mJ were used. The detailed analytical technique and data-correction procedure are described in Wu et al (2006) Hf ratio of 0.282284 ± 3 (1r) measured using the solution method (Woodhead et al, 2004).…”

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confidence: 99%

Constraints on the paleogeographic evolution of the North China Craton during the Late Triassic–Jurassic

Huang

2013

Journal of Asian Earth Sciences

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Zircon Hf-isotope analysis with an excimer laser, depth profiling, ablation of complex geometries, and concomitant age estimation

Cited by 833 publications

References 27 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?

Hidden Archaean and Palaeoproterozoic crust in NW Ireland? Evidence from zircon Hf isotopic data from granitoid intrusions

Constraints on the paleogeographic evolution of the North China Craton during the Late Triassic–Jurassic

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