Zircon U-Pb (LG-SIMS)
Zircon has long been recognized as the most important geochronometer, and several key instrumental features of the CAMECA large-geometry SIMS make it the best suited instrument for zircon U-Pb dating, among which:
High mass resolution for peak separation between HfSi molecular ions and Pb isotopes
High transmission for analysis of low lead concentration
Oxygen flooding for improved sensitivity and highly reproducible analytical conditions
Small spot size with high beam density for better lateral resolution
Outstanding ion image capability for Pb and U mapping in zircon grains (inhomogeneity, zonation)
From old to (very) young zircon dating with excellent precision
Accurate zircon geochronology with good spatial resolution requires advanced microanalytical tools capable of dating small minerals within their petrographic context and/or domains in single crystals.
Above, first U-Pb direct dating of iron oxide-copper-gold (IOCG) mineralization. Hydrothermal zircon crystals from IOCG-type ore deposits (Lyon Mountain, US). Data from P.M. Valley et al., Geology 37 (2009), p.223.
Below, lower-intercept age (Th corrected data) for young Quaternary zircon (Chinkuashi dacite, Taiwan). Data from Y. Gao et al., Earth Science Frontiers 17 (2010), p.146.
Although zircon is by far the most commonly utilized mineral for U–Th-Pb dating, monazite, apatite, titanite, rutile and baddeleyite are also commonly dated and provide a wide spectrum of geochronological applications, all perfectly addressed by CAMECA IMS 1280-HR. To learn more, download our application note: Advanced U-Th-Pb Geochronology with CAMECA Ultra High Sensitivity SIMS.