U–Th/Pb geochronology of detrital zircon and monazite by single shot laser ablation inductively coupled plasma mass spectrometry (SS-LA-ICPMS)

Cottle, John M.; Kylander-Clark, Andrew R.C.; Vrijmoed, Johannes C.

doi:10.1016/j.chemgeo.2012.09.035

Cited by 88 publications

(71 citation statements)

References 27 publications

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“…This material is then introduced into an ICP-MS and isotope ratios analyzed by mass spectrometry. Compared to SIMS, the LA-ICP-MS technique involves destruction and removal of more material with typical spot sizes of 30-60 microns and depths of 10-20 microns, although recent studies are demonstrating successful application of single shot laser ablation analysis with small spot sizes (down to 6 microns) (Cottle et al 2009(Cottle et al , 2012. The availability, lower capital cost of the instrumentation compared to TIMS and SIMS, and the capability of obtaining ages from 100s of unknowns in a single analytical session has resulted in widespread application of U-Pb dating by LA-ICP-MS over the past 5-10 years (Fisher et al 2010).…”

Section: In Situ Methods (Sims La-icp-ms)mentioning

confidence: 99%

Geochronology of Layered Intrusions

Scoates

Wall

2015

Springer Geology

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Layered intrusions crystallize mainly from basaltic magma to form large bodies of igneous rocks that exhibit prominent layering and they preserve stunning rock records of the processes by which magma evolves in crustal magma chambers. These intrusions contain world-class deposits of chromium, platinum group elements (PGE), and vanadium, metals that are vital to industry and society in general. Despite their scientific and practical importance, precise age constraints are lacking for many layered intrusions, and geochronological frameworks linking crystallization and cooling ages for the most part do not exist. This has resulted in critical knowledge gaps related to their origin and formation. This chapter provides an overview of dating methods (U-Th-Pb, 40 Ar/ 39 Ar) and mineral chronometers (e.g., zircon, baddeleyite, rutile, apatite, titanite) potentially present in layered intrusions that is coupled with field, textural, and petrographic criteria for targeting sample selection to allow for the successful implementation of geochronologic studies of layered mafic-ultramafic rocks of any age. As an application, we demonstrate how the thermal history of the Bushveld Complex is documented by mineral ages from samples of the PGE-rich Merensky Reef. High-precision U-Pb zircon ages, involving pretreatment of zircon by the chemical abrasion (annealing and leaching) or CA-TIMS technique, for two samples separated by > 300 km are indistinguishable from each other (2056.88 ± 0.41 Ma, Eastern Limb; 2057.04 ± 0.55 Ma, Western Limb; uncertainty reported as 2s) confirming synchronous crystallization of this horizon at near-solidus conditions across the intrusion. Rapid cooling (~ 125 °C/Ma) down to temperatures of ~ 400-450 °C is defined by U-Pb rutile ages from the same samples (2052( .96 ± 0.61 Ma, 2053.0 ± 2.7 Ma) and a regional hydrothermal event is signaled in 40 Ar/ 39 Ar biotite ages (1999 ± 10 Ma, 2002 ± 10 Ma). The geochronology of layered intrusions, where magma differentiation processes are captured in a wide range of rock textures and structures, represents an essential tool for assessing the evolution of mafic magmatism in the Earth's crust.

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Section: In Situ Methods (Sims La-icp-ms)mentioning

confidence: 99%

Geochronology of Layered Intrusions

Scoates

Wall

2015

Springer Geology

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“…Data reduction followed the methods of Cottle et al (2009Cottle et al ( , 2012. All of the data for secondary reference material GJ1 returned 206 Pb/ 238 U and 207 Pb/ 206 Pb ratios with an MSWD value too high for the data to be a single population (Wendt and Carl, 1991) (see Supplementary material); the same was observed for the Plešovice secondary reference material.…”

Section: U-pb Zircon Ss-lassmentioning

confidence: 83%

“…Each SS-LASS analysis (including cleaning shots) samples an~100 nm layer of zircon (Cottle et al, 2009(Cottle et al, , 2012Kylander-Clark et al, 2013). Consecutive analyses were separated by a 12 s pause.…”

Section: U-pb Zircon Ss-lassmentioning

confidence: 99%

“…More recently, LA-ICP-MS has also been used for depth profiling. Studies employing LA-ICP-MS use either continuous-pulse (e.g., Plotnikov et al, 2001;Woodhead et al, 2004;Johnston et al, 2009;Kohn and Corrie, 2011;Smye and Stockli, 2014;Kelly et al, 2014) or singlepulse techniques (Cottle et al, 2009(Cottle et al, , 2012Steely et al, 2014;Stearns et al, in review). The single-shot technique presents some significant obstacles to extraction of reliable data (Cottle et al, 2009(Cottle et al, , 2012, but offers the advantage of using significantly smaller volumes of material (i.e.…”

Section: Introductionmentioning

confidence: 98%

“…First, the small volume of analyte needed for SS-LA-ICP-MS depth profiling results in less mixing of different depths within the crystal, providing better spatial resolution. SS-LA-ICP-MS depth profiling is capable of resolving an order of magnitude smaller variation than can be sampled by LA-ICP-MS on sectioned grains (e.g., Cottle et al, 2009Cottle et al, , 2012; this also makes grains with rims thinner than laser spot diameter tenable for analysis. Second, the SS-LA-ICP-MS surface analysis method is quick (~3-6 min per grain) and relatively inexpensive, allowing collection of the vast datasets required to confidently resolve short-duration metamorphic age populations (e.g., Pullen et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Single-shot laser ablation split stream (SS-LASS) petrochronology deciphers multiple, short-duration metamorphic events

2015

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Midcrustal discontinuities and the assembly of the Himalayan midcrust

Larson

Cottle

2014

Tectonics

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Detailed quartz lattice preferred orientation (LPO) data define two structural discontinuities in the exhumed high-grade metamorphic core of the Himalaya exposed in the upper Tama Kosi region of east central Nepal. The structures are marked by abrupt breaks in a general trend of up structural section increasing quartz LPO-defined deformation temperatures. Deformation associated with the upper structural discontinuity, which occurs within sillimanite grade rocks, is postpeak metamorphism in both the hanging wall and the footwall. New geochronologic data constrain the timing of metamorphism in the hanging wall of the upper discontinuity to between 24 and 16 Ma, indistinguishable from previously published ages for the footwall. Movement across this structure represents Early Miocene strain localization and thickening in the Himalayan midcrust. Movement across the lower discontinuity, which occurs between staurolite and kyanite grade rocks, appears to be synmetamorphic with material in its footwall at approximately 10 Ma, but postpeak metamorphism for material in its hanging wall. This movement is interpreted to reflect the underplating and incorporation of material into the metamorphic core. The recognition of two thrust-sense discontinuities in the exhumed Himalayan core in the Tama Kosi region is consistent with other similar structures recognized along the Himalaya. The widespread nature of these structures reinforces that they are important to our understanding of the evolution of the kinematics of large, hot orogens.

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U–Th/Pb geochronology of detrital zircon and monazite by single shot laser ablation inductively coupled plasma mass spectrometry (SS-LA-ICPMS)

Cited by 88 publications

References 27 publications

Geochronology of Layered Intrusions

Geochronology of Layered Intrusions

Single-shot laser ablation split stream (SS-LASS) petrochronology deciphers multiple, short-duration metamorphic events

Midcrustal discontinuities and the assembly of the Himalayan midcrust

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