Isotopic discordance is a common feature in zircon that can lead to an erroneous age determination, and it is attributed to the mobilization and escape of radiogenic Pb during its post-crystallization geological evolution. The degree of isotopic discordance measured at analytical scales of ~10 μm often differs among adjacent analysis locations, indicating heterogeneous distributions of Pb at sh...

Corrosion resistance of zircon reinforced alumina refractories has been carried out through static crucible test. The corrosion measurements with percentage, the penetration depth of molten steel and the microstructure of the refractories were evaluated after soaking 150 h at the temperature of 1500˚C. Results showed that the corrosion resistance of alumina increased by adding 20 wt% zirc...

Radiation and thermally induced changes in the oxidation state of uranium in metamict zircon have been systematically analysed, for the first time, using polarized near-infrared spectroscopy. The results showed that in damaged zircon U ions in crystalline domains exhibited relatively sharp, anisotropic signals from tetravalent and pentavalent U ions in crystalline domains (U4+ crystal and U5+ c...

To evaluate the potential of (U–Th)/He geochronometry and thermochronometry of zircon, we measured He diffusion characteristics in zircons from a range of quickly and slowly cooled samples, (U–Th)/He ages of zircons from the quickly cooled Fish Canyon Tuff, and age-paleodepth relationships for samples from 15 to 18 km thick crustal section of the Gold Butte block, Nevada. (U–Th)/He ages of zirc...

a r t i c l e i n f o The Yangtze River dominates the drainage of eastern Asia, yet the processes that control erosion within the basin are obscure, making the interpretation of the detritus record difficult. In this study we used U–Pb dating of zircon grains from the modern main stream and major tributaries to identify the sources of sediment production, based on the diversity of zircon ages a...

The effects of crystal-plasticity on the U-Th-Pb system in zircon is studied by quantitative microstructural and microchemical analysis of a large zircon grain collected from pyroxenite of the Lewisian Complex, Scotland. Electron backscatter diffraction (EBSD) mapping reveals a c.18 degree variation in crystallographic orientation that comprises both a gradual change in orientation and a series...

Zircon (ZrSiO4) is the most commonly used mineral in U–Pb geochronology. Although it has proven to be a robust chronometer, it can suffer from Pb-loss or elevated common Pb, both of which impede precision and accuracy of age determinations. Chemical abrasion of zircon involves thermal annealing followed by relatively low temperature partial dissolution in HF acid. It was specifically developed ...

Zirconand reidite-type ZrSiO4 produced by shock recovery experiments at different pressures have been studied using infrared (IR) and Raman spectroscopy. The n3 vibration of the SiO4 group in shocked natural zircon shows a spectral change similar to that seen in radiation-damaged zircon: a decrease in frequency and increase in linewidth. The observation could imply a possible similar defective ...

Simultaneous acquisition of detrital zircon Pb-Pb ages and trace element abundances from grains collected across the Indian craton, spanning ~3 b.y., reveals prominent shifts in Eu/ Eu* and light and middle to heavy rare earth element ratios. These shifts correspond to a ca. 3.0–2.2 Ga interval of crustal thickening during Indian craton formation, followed by a period wherein arc magmatism occu...

New empirical calibrations for the fractionation of oxygen isotopes among zircon, almandine-rich garnet, titanite, and quartz are combined with experimental values for quartz-grossular. The resulting A-coefficients (‰K) are: for the relation 1000 ln Y-X AY-X (10 /T). The fractionation of oxygen isotopes between zircon and coexisting minerals can provide otherwise unavailable evidence of magmati...