Age of subducting oceanic lithosphere at trench

Hi,
I’d like to extract the age of the subducting oceanic lithosphere from a model (e.g., from the files of Seton et al., 2012) along the trench. I’m specifically interested in the age of subducting oceanic lithosphere at the trench of plate 201 from 70 - 0Ma.
I’m think this is something that can be done with Plate tectonic tools, however I am a newbie and can’t get it to work! Any assistance would be appreciated!

Thanks,
Alex