Garnet and zircon petrochronology reveal coherent subduction and exhumation of eclogites and associated schists in the Changning-Menglian belt, southeast Tibet

Determining whether high-grade metamorphic eclogites and surrounding metasediments underwent a shared subduction-exhumation cycle or distinct metamorphic paths before their juxtaposition at shallow levels is crucial for deciphering metamorphic processes in orogenic belts. Constructing pressure-temperature-time (P-T-t) paths for both rocks is the most straightforward approach. However, current time constraints overwhelmingly rely on dating accessory mineral like zircon, rutile, and monazite, which may only record a portion of the entire metamorphic history. Here we present an integrated petrochronological analysis using garnet Lu-Hf and Sm-Nd, and zircon U-Pb on two eclogites and their surrounding micaschists from the Changning-Menglian orogenic belt in southeast Tibet. Pseudosection modelling and conventional thermobarometers suggest a clockwise P-T path for the eclogites, from similar to 1.4 GPa/similar to 520 degrees C to similar to 2.5 GPa/similar to 600 degrees C, followed by decompression to 更多