That assumption is particularly true of clay deposits found in crater central peaks. (sciencedaily.com)
The fact that the deposits were found on central peaks is a good indicator that they have an impact origin. (sciencedaily.com)
Among these were Copernicus, Gassendi and Tycho, large impact craters containing central peaks that were thrust upward at the time of impact, bringing material from deep within the lunar crust to the surface. (scientificamerican.com)