https://www.theregister.co.uk/2018/07/25/mars_dust_medusae_fossae/

Have you ever wondered where Mars got all that striking iron-rich rust-colored dust from?

Weirdly enough, it appears it is mostly drawn from a formation on its surface called the Medusae Fossae, a single geological object that is slowly crumbling and scattering debris all over the Red Planet.