A zircon classification scheme for sedimentary provenance analysis using radiation damage

Detrital single-grain zircon U-Pb geochronology is a powerful tool for provenance studies if information on the source rocks is available. This paper proposes a new source-rock classification tool that uses the degree of annealing of radiation damage in detrital zircon; the annealing is expressed by the relationship between the width (full-width at half-maximum; FWHM) of the v(3)[SiO4] Raman band at similar to 1008 cm(-1) and the calculated a-dose. The host rocks of the zircons are classified into three types according to their emplacement process and/or thermal history: volcanic and rapidly cooled plutonic and high-grade metamorphic rocks (type 1); rocks with hydrothermal zircons (type 2); slowly cooled igneous and metamorphic rocks (type 3). We construct a naive Bayes prediction model by training it with a collection of zircons of known types. The unknown zircons are assigned a probability of derivation from a specific host-rock type. This classification scheme is best used as an accessory tool in provenance studies that apply detrital zircon U-Pb geochronology.