裂变径迹与(U-Th)/He年龄倒转的成因机理及地质意义OA

The exhumation of geological bodies is a product of interactions among Earth's spheres.Precisely deter-mining the timing and processes of exhumation has become a crucial aspect of modern Earth system science.Ther-mochronological techniques,particularly fission-track and(U-Th)/He dating,play a central role in this endeavor.Conventionally,for the same mineral type within a single rock sample,the fission-track age should be greater than or equal to the corresponding(U-Th)/He age.However,the phenomenon of the(U-Th)/He age appears older than the fission-track age,and significant dispersion of single-grain(U-Th)/He ages beyond analytical error are common yet often overlooked anomalies in low-temperature thermochronology.This paper aims to clarify potential misconceptions in interpreting thermochronological data and provides a concise yet systematic review of the interplay among factors such as the accumulation and annealing of radiation damage,the U-Th zonation,thermal history,and mineral chemical composition.These factors can significantly alter the annealing behavior of fission tracks and the diffusion behavior of 4He within crystals,leading to a decrease in the fission-track annealing temperature and an in-crease in the(U-Th)/He closure temperature,thereby resulting in age inversion.The dispersion of single-grain(U-Th)/He ages and the inversion between fission-track and(U-Th)/He ages often carry important geological information,providing key clues for interpreting complex thermal histories.