Optimization of the in-situ U–Pb age dating method via LA-Quadrupole-ICP-MS with applications to the timing of U–Zr–Mo mineralization in the Poços de Caldas Alkaline Complex, SE Brazil

摘要: Abstract The high spatial resolution of the LA-ICP-MS systems allows rapid extraction vital isotopic information from individual growth zones minerals. This paper describes in detail optimization a relatively inexpensive system consisting UV 213 Laser Ablation and Quadrupole ICP-MS. results take into account laser energy, beam diameter, frequency ICP-MS gas conditions. optimized conditions were tested for precision accuracy on number well-characterized zircons, commonly used as primary secondary quality control standards. acquisition U–Pb data is carried out automated mode (pre-set points) up to 12 h/day with only minimal operator presence. Individual zircon analysis lasts 80 s. 2 σ uncertainties standards ranged between 1.4 8.2%, overall their relative deviations 0.02 0.87%. are comparable techniques that use more complex time-consuming approaches such LA-MC-ICP-MS ion-microprobe. We have applied this method obtain ages numerous granitoid rocks Southern Sao Francisco Craton well-known Archean Kaapvaal Craton, South Africa. furthermore provide first age dating U–Zr–Mo mineralization Pocos de Caldas Alkaline Complex, SE Brazil, 85 ± 3 Ma zircon-bearing hydrothermal veins.