Improvement in the Analytical Capabilities of LA-ICP-MS for High Spatial Resolution U-Pb Dating of Zircon Using Mixed-Gas Plasma

Figure 4

(a) U-Pb concordia diagrams and ²⁰⁶Pb/²³⁸U ages of zircon SRM 91500 determined under different experimental conditions. The blue solid line represents the weighted mean ²⁰⁶Pb/²³⁸U ages, while the dotted line represents the reference ²⁰⁶Pb/²³⁸U age of SRM 91500 obtained from [21]. Uncertainties are represented by 2σ, while MSWD is the mean square of weighted deviations. Experimental conditions: (1) plasma conditions (dry plasma or 2% ethanol plasma), (2) spot sizes (16, 24, or 32 μm). The reason for the missing data of SRM 91500 at the spot diameter of 10 μm is feeble signal of U and Th resulting error ages.

(a)

(b)