Evolution of spectra due to different irradiation methods. Left: olivine irradiated by (a) hydrogen (H⁺), (b) helium (He⁺), and (c) argon (Ar⁺) ions, and (d)femtosecond pulsed laser with various ion fluences (ions cm⁻²) or energy densities (J cm⁻²) (see Sect. 2.3 for more details). Right: (e–h) pyroxene undergoing the same processing described for olivine in the left panel. In the graphs R stands for reflectance and λ is the wavelength. The arrows in (a) and (e) indicate the position of the diagnostic mineral bands; the smallest arrow in (e) refers to the position of the only visible pargasite band.