After crushing and washing, the sample is preliminarily sorted using reselection and magnetic separation techniques, and then manually selected under binocular vision. Stick representative zircons onto epoxy resin for target preparation, polish to expose 1/3~1/2 crystal planes, and perform microscopic photography. The cathodoluminescence imaging instrument is a high vacuum scanning electron microscope (JSM-IT100) equipped with GATAN MINICL system.

  2. Zircon U-Pb dating analysis was carried out using a combined device of RESOLution LR 193 nm laser ablation system and ICAP-Q inductively coupled plasma mass spectrometry (LA-ICP-MS). The laser beam spot diameter used for analysis is 29 µ m, the laser beam energy density is 4 J/cm², and the frequency is 3 Hz. During sample testing, the analysis time for each point is 90 seconds, including 15 seconds for background signal, 45 seconds for sample erosion, and 30 seconds for tail blowing. Zircon U-Pb dating analysis uses zircon reference material 91500 as an external standard for isotope fractionation correction. The isotopic ratios and elemental contents of zircon samples were analyzed using the ICPMSDataCal software for data processing. The calculation and plotting of U-Pb harmonic age and weighted average age were completed using the software Isoplot 3.0. Use the EXCEL program ComPbCorr # 3_15G for regular lead correction. For zircons greater than or equal to 1000 Ma, select²⁰⁷Pb/²⁰⁶Pb age. For zircons less than 1000 Ma, select²⁰⁶Pb/²³⁸U age, and exclude ages with a Concordance less than 90%. Finally, use Isoplot R to create a detrital zircon age frequency histogram and age harmonic plot.

  3. Zircon Lu Hf isotope analysis was performed using a combined device of RESOLution LR 193 nm laser ablation system and ICAP-Q inductively coupled plasma mass spectrometry (LA-ICP-MS). The laser beam spot diameter is 43 µ m, the laser ablation time is 60 s, the laser frequency is 6 Hz, and the laser energy density is 4 J/cm². During the analysis process, zircon standard materials Ple š ovice and Penglai were used as monitoring samples, and zircon Hf isotope data processing and analysis were completed using software ICPMSDataCal.