Multi-stage zircon and monazite growth revealed by depth profiling and in situ U–Pb geochronology: Resolving the Paleoproterozoic tectonics of the Trans-Hudson Orogen on southeastern Baffin Island, Canada

High-spatial resolution dating of monazite and zircon reveals the timing of subduction–exhumation of the Vaimok Lens in the Seve Nappe Complex (Scandinavian Caledonides)

“…However, in contrast to these studies (i.e. Kelly et al 2017;Skipton et al 2016) we did not apply a 204 Pb/ 206 Pb cut-off for screening the data as the uncertainties of the ratio often equalled the reported value, thus this cut-off method was deemed unreliable for our data. Instead, we applied the 204 Pb-correction built into VisualAge data reduction scheme (Petrus and Kamber 2012) to all rim integrations.…”

“…Zircon rim dates were defined from analyses of Ablation Pit 2, according to 206 Pb/ 238 U and Th/U ratios (Supplementary Table A3), the decrease of the latter correlates to the enrichment of LREE observed in the trace element concentration profiles from Ablation Pit 1. In accordance with previous depth-profiling studies (March and Stocki 2015; Kelly et al 2017;Skipton et al 2016), we utilized the Wetherill Concordia diagram to plot our rim integrations. However, in contrast to these studies (i.e.…”

“…conditions, retrogressive metamorphism and deformation (e.g. Engi 2017;Foster et al 2000;Harley et al 2007;Rubatto 2017;Rubatto et al 2001;Schneider et al 2011;Skipton et al 2016;Walczak et al 2017). However, monazite and zircon domains that record such important information regarding prograde metamorphism are often minute, commonly with volumes on the scale of a few micrometers.…”

“…Zircon depth-profiling, using either Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) or Secondary Ion Mass Spectrometry (SIMS), has proven to be a powerful technique to extract radiogenic isotopes and trace elements from micrometerscale rims (e.g. Breeding et al 2004;Kelly et al 2014Kelly et al , 2017Marsh and Stockli 2015;Schneider et al 2011;Skipton et al 2016;Woodhead et al 2004). We applied these techniques to accessory phases hosted in the (U)HP rocks of the Seve Nappe Complex (SNC), Scandinavian Caledonides (Fig.…”

U-Pb memory behavior in Chicxulub's peak ring — Applying U-Pb depth profiling to shocked zircon

“…This behavior is not a systemic artifact of depth-profiling, but clearly related to the particular zircon petrogenesis, likely caused by progressive magma fractionation. However, U-Pb SIMS depth profiling has also demonstrated the U and Th increase at grain edges on the micron-scale, interpreted as secondary zircon precipitation due to metamorphic-induced fluid flow (Breeding et al, 2004;Kelly et al, 2014;Skipton et al, 2016). Progressively decreasing U and Th concentrations have also been reported in zircon from CA-TIMS U-Pb step dissolution experiments (Mattinson, 2005), with U and Th concentrations being higher in initial leachates of stepwise dissolutions.…”