Detrital Zircon Geochronology by Laser-Ablation Multicollector ICPMS at the Arizona LaserChron Center

Abstract

Detrital zircon geochronology is rapidly evolving into a very powerful tool for determining the provenance and maximum depositional age of clastic strata. This rapid evolution is being driven by the increased availability of ion probes and laser ablation ICP mass spectrometers, which are able to generate age determinations rapidly, at moderate to low cost, and of sufficient accuracy for most applications. Improvements in current methods will probably come from enhanced precision/accuracy of age determinations, better tools for extracting critical information from age spectra, abilities to determine other types of information (e.g., REE patterns, O and Hf isotope signatures, and/or cooling ages) from the dated grains, and construction of a database that provides access to detrital zircon age determinations from around the world.

Tectonomagmatic setting and provenance of the Santa Marta Schists, northern Colombia: Insights on the growth and approach of Cretaceous Caribbean oceanic terranes to the South American continent

“…A single Cambrian to Mesoproterozoic and an Early Archean grain were also recovered. Although statistically limited (Gehrels et al, 2006), these results suggest that older continental sources were also feeding this basin during deposition. Zircons from the Rodadero Formation (sample S8) are also characterized by typical magmatic U/Th ratios < 12 (Rubatto, 2002).…”

Detrital mineral ages from the Ross Supergroup, Antarctica: Implications for the Queen Maud terrane and outboard sediment provenance on the Gondwana margin

“…Mineral concentrates were obtained by conventional mineral separation techniques and mounted in epoxy in a 1″ phenolic ring. U-Pb geochronology of zircons was conducted by Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICPMS) at the Arizona LaserChron Center (Gehrels et al, 2006(Gehrels et al, , 2008. The analyses involve ablation of zircon with a New Wave/Lambda Physik DUV193 Excimer laser (operating at a wavelength of 193 nm) using a spot diameter of 35 μm.…”

U–Pb geochronological constraints on the Triassic–Jurassic Ayú Complex, southern Mexico: Derivation from the western margin of Pangea-A

“…Hence, zircon analyses with >90% concordance are used to date the time of intrusion in igneous rocks or the maximum age of deposition in metasedimentary rocks. The latter is considered robust if it belongs to a cluster of three or more zircons with similar ages (Gehrels et al, 2006). In some samples, however, a statistically large number of concordant grains was not attainable.…”