Division of crustal units in China using grid-based clustering and a zircon U–Pb geochronology database

Abstract Zircon U–Pb dating is one of the most effective and widely used methods due to the widespread existence of zircon as an accessory mineral in rocks and its high closure temperature. Throughout history, each region of the earth has experienced its own crustal evolution. Using zircon U–Pb geochronology data, researchers can reveal the crustal growth history and regional discrimination. In this study, a large spatial analysis was performed across China, involving more than 120,000 data records taken from the zircon U–Pb geochronology database. By applying the Gaussian multipeak fitting method, nine age peaks corresponding to crustal growth events on the continent of China were identified, which centered at 45, 132, 249, 441, 815, 1236, 1908, 2505, and 2933 Ma. Using a grid-based clustering algorithm, grids with similar crustal growth event combinations were gathered and their features extracted. Based on the time series of the crustal growth events, the gathered grid clusters were further integrated into larger crustal units. We used various grid sizes in our algorithm, including 0.325 ° × 0.325 °, 0.4 ° × 0.4 °, 0.6 ° × 0.6 °, 0.8 ° × 0.8 °, 1.0 ° × 1.0 °, 1.2 ° × 1.2 °, and 1.4 ° × 1.4 °. Although the shape and number of the crustal units varied depending on grid size, six large entities were clearly identified and were best visualized using the 0.8 ° × 0.8 °, 1.0 ° × 1.0 °, 1.2 ° × 1.2 °, and 1.4 ° × 1.4 ° grids. These six entities include the Tibet-Sichuan-Yunnan, North Xinjiang, Northeast, Gansu-Qinghai, North China, and South China units. Furthermore, while there were some variations, the crustal unit results found herein were in agreement with tectonic unit research, displaying a new potential avenue of research.