Tolstoj basin materials. (A) MDIS enhanced color mosaic in simple cylindrical projection centered near the northern rim of Tolstoj basin (11°S, 196°E). Green circles are craters N(20) as mapped by C. I. Fassett et al. (2011). Yellow outlines are volcanic smooth plains deposits as mapped by B. W. Denevi et al. (2013). (B) Mariner 10 UV/OR ratio of the same scene at 4 km px⁻¹. (C) Mariner 10 UV/OR ratio along profiles X–X’ and Y–Y’ as delineated in (A) and (B). LRM deposits and fresh crater ejecta (blue asterisks near peaks) are associated with the highest ratio-reflectance values, while smooth plains and faculae (orange asterisks near troughs) have the lowest.