Fundamental studies on the ablation behaviour of Pb/U in NIST 610 and zircon 91500 using laser ablation inductively coupled plasma mass spectrometry with respect to geochronology

Kühn, Barbara; Birbaum, Karin; Luo, Yan; Günther, Detlef

doi:10.1039/b917261k

Cited by 51 publications

(53 citation statements)

References 18 publications

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“…1c right bottom panel). Zircons (ZrSiO 4 ) has different ablation properties (Kuhn et al, 2010) and the molten walls may be due to selective ablation of SiO 2 , with ZrO 2 being left over as reported elsewhere (Eggins et al, 1998). Such the molten wall was not observed for 200FsLA, only smooth surfaces were formed on and around the crater walls and fringes (see the crater wall close up in Fig.…”

Section: Laser Crater Profilesmentioning

confidence: 85%

Optimization of ablation protocol for 200 nm UV femtosecond laser in precise U^|^ndash;Pb age dating coupled to multi-collector ICP mass spectrometry

2011

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Section: Laser Crater Profilesmentioning

confidence: 85%

Optimization of ablation protocol for 200 nm UV femtosecond laser in precise U^|^ndash;Pb age dating coupled to multi-collector ICP mass spectrometry

2011

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“…The homogenized, focused laser beam diameter was fixed at 40 lm. The accuracy and reproducibility of U-Pb zircon dating with NIST SRM 610 as external standard reference material is not as good as with matrix matched zircon as reference material (Kuhn et al 2010). Therefore, we monitored the accuracy and reproducibility within each run of analysis by analysing zircon reference materials, e.g., BR266 with 206 Pb/238 U and 207 Pb/ 206 Pb ages between 559.0 ± 0.3 and 562.2 Ma (Stern 2001), to be able to correct the age of the samples.…”

Section: Samples and Methodsmentioning

confidence: 99%

Laser ablation U/Pb age patterns of detrital zircons in the Schlieren Flysch (Central Switzerland): new evidence on the detrital sources

2011

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The palaeogeographic attribution of the Schlieren Flysch and its counterparts in the Gurnigel Nappe is still a matter of debate. These Late Alpine deepsea trench deposits show a variable tectonic thrust relationship with other nappes inferring either an Ultrahelvetic or South Penninic origin of the elongated trench basin. An improved knowledge of the supplying source terranes of the Schlieren Flysch basin may add to the palaeogeographic ascription. Detrital zircons from seven representative samples have been dated by laser ablation ICP-MS analysis methods. The obtained age patterns are compared with standard provenance analysis methods including modal grain and heavy mineral statistics of the sandstones. The detrital zircons show two major populations of Pan-African (ca. 650-450 Ma) and Variscan (ca. 360-320 Ma) ages. A low abundance of Devonian detrital zircons separates the two main age populations. The Th/U signature of the zircons implies that igneous rocks of these two orogenic cycles directly, or indirectly (by multicyclic reworking of zircons) have strongly contributed to the clastic input. The earlier described bimodal turbiditic supply to the Schlieren Flysch basin is matched by the geochronologic data. With regard to the other petrographic signatures of the sandstones, it becomes evident that the granitic-rhyolitic source terrane derived (K-feldspar bearing) sandstones show a higher abundance of Pan-African zircons and a higher abundance of tourmaline in the heavy mineral fractions. In contrast, the exclusively plagioclase-bearing sandstones from the tonalitic-andesitic source contain a majority of Variscan zircons and higher contents of apatite. In addition, we observe a third minor population comprising TriassicEarly Jurassic detrital zircons. The correlation of the obtained detrital zircon ages with pre-Cretaceous igneous, metamorphic and geodynamic events, which affected the basement of the northern and southern margins of the Alpine Tethys reveals a major difference by the presence of Triassic magmatic products and volcaniclastics in South Alpine and Austroalpine units. The discovery of the minor Triassic-Early Jurassic population in both sandstone types of the Schlieren Flysch would argue for the derivation of the clastic material from the southern Alpine Tethys or Adriatic-Apulian margin.

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“…The most practicable means by which LIEF can be minimised however, is by ensuring craters are of a critical aspect ratio (depth/diameter) <1 Mason, 1999, 2001). For zircon, a high affinity of U (and Hf) for Zr results in its retention within the crater during a laser induced phase transition of SiO 2 to ZrO 2 (Kuhn et al, 2009). Both Si and Pb show no such a nity and freely are mobilised out of ablation craters as condensate independently of their diameter (Košler et al, 2005, Kuhn et al, 2009.…”

Section: Introductionmentioning

confidence: 99%

“…For zircon, a high affinity of U (and Hf) for Zr results in its retention within the crater during a laser induced phase transition of SiO 2 to ZrO 2 (Kuhn et al, 2009). Both Si and Pb show no such a nity and freely are mobilised out of ablation craters as condensate independently of their diameter (Košler et al, 2005, Kuhn et al, 2009. U reten-tion during ablation was shown by Kuhn et al (2009) to be crater-size dependent.…”

Section: Introductionmentioning

confidence: 99%

Shallow sampling by multi-shot laser ablation and its application within U-Pb zircon geochronology

et al. 2020

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The interaction of incident laser radiation and sample substrate is complex and difficult to predict. Natural zircons are often both structurally and chemically heterogeneous in 3-dimensional space. Encountering growth-related, structural micro-heterogeneities, inclusions and chemical complexities is almost inevitable during a static ablation of several tens of seconds. A multi-shot approach to laser ablation described here implements a minimal sample exposure time to incident laser radiation by applying multiple 1 Hz shots to a single sample location in delayed succession. This process can be conceptualised as a "slowing down" of a high-frequency (5-20 Hz) static laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis until each laser pulse is distinct albeit transient. The ability to integrate and collate signal pulses for a small number of consecutive laser shots, as opposed to continuously pulsing the laser, produces precise age determinations (~1% reproducibility, 2σ level) on small sample volumes (704 ± 23 μm3 on 91500 zircon standard). The multi-shot LA-ICP-MS protocol employed here significantly reduces the effect of 'downhole' fractionation as the resultant craters are extremely shallow (as shallow as 0.56 ± 0.02 μm on 91500 zircon standard) and maintain an aspect ratio of 1. Further benefits include a reduced probability of thermally induced effects (e.g., substrate melting), plasma loading, and the potential for signal mixing (with depth) in a heterogeneous sample.

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Fundamental studies on the ablation behaviour of Pb/U in NIST 610 and zircon 91500 using laser ablation inductively coupled plasma mass spectrometry with respect to geochronology

Cited by 51 publications

References 18 publications

Optimization of ablation protocol for 200 nm UV femtosecond laser in precise U^|^ndash;Pb age dating coupled to multi-collector ICP mass spectrometry

Optimization of ablation protocol for 200 nm UV femtosecond laser in precise U^|^ndash;Pb age dating coupled to multi-collector ICP mass spectrometry

Laser ablation U/Pb age patterns of detrital zircons in the Schlieren Flysch (Central Switzerland): new evidence on the detrital sources

Shallow sampling by multi-shot laser ablation and its application within U-Pb zircon geochronology

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