In situ U-Pb dating and trace element determination of standard zircons by LA-ICP-MS

The age and trace elements of 91500, GJ-1, Plešovice and Qinghu standard zircons were analyzed simultaneously by using Agilent 7700X inductively coupled plasma-mass spectrometry (ICP-MS) and Photo Machines Analyte Excite 193nm laser ablation at the laboratory of mineralization and dynamics, Chang'an University, with the laser frequency being 5Hz and laser ablation spot size being 35μm. According to the results obtained, the ²⁰⁶Pb/²³⁸U age range of 20 test points of 91500 zircon is between 1059Ma and 1070Ma, and its weighted average of ²⁰⁶Pb/²³⁸U age is 1063.8±6.6Ma; the ²⁰⁶Pb/²³⁸U age range of 28 test points of GJ-1 zircon is between 601Ma and 610Ma, and its weighted average of ²⁰⁶Pb/²³⁸U age is 605.4±3.0Ma; the ²⁰⁶Pb/²³⁸U age range of 28 test points of Plešovice zircon is between 336Ma and 341Ma, and its weighted average of ²⁰⁶Pb/²³⁸U age is 338.8±1.4Ma; the ²⁰⁶Pb/²³⁸U age range of 40 test points of Qinghu zircon is between 158Ma and 165Ma, and its weighted average of ²⁰⁶Pb/²³⁸U age is 159.9±0.7Ma. The results show that the ²⁰⁶Pb/²³⁸U age ranges of four standard zircons 91500, GJ-1, Plešovice and Qinghu are in accordance with the recommended values within reasonable error range, and the weighted average age shows an excellent agreement with the previously reported data. All the trace element compositions of four standard zircons fall into the range of the literature available. Chondritenormalized REE distribution curves of these standard zircons show that the relative content of rare earth elements obtained is accurate. The above results show that in situ U-Pb dating and trace element determination of zircon can be carried out by using the method established in this study, and the results are accurate and reliable.