Effect of tectonic stress on isotopic systems in dating minerals

Temperature is recognized as the only dominant factor that affects the opening and closing of isotope system, based on which thermochronology has well developed. However, there are some research shows that stress could also matter. The muscovite K-Ar ages of Sanbagawa (Japan) schists are consistently younger with increasing deformation extent (Tetsumaru, 1988), which revealed that tectonic deformation can have influence on isotopic ages. On a microscopic scale, elements like Pb can redistribute in zircon lattice during dislocation (Piazolo,2015). The behaviors of isotopic systems in dating minerals under stress involve the fundamental problem of isotopic chronology. The application of it can be very wide, it allows us to get the deformation age directly if we choose the right deformed minerals in the right way. Some of the works such as fault, fold and ductile shear zone dating by our lab has been published (Yu Wang, 2010, 2016, 2020). What role does stress play in isotope diffusion which in turn affects ages is what we are eager to know. We designed a set of experiments using three axles press to work on undeformed K-feldspars with known age (126Ma) to test the effects. Rock mechanics experiments, field observation and isotopic dating are combined to give us an insight to it.