Mars Dichotomy Boundary Eroded Hundreds of Kilometers
New research suggests Mars' iconic dichotomy boundary, separating the higher southern hemisphere from the lower northern one, may have receded hundreds of kilometers due to water erosion. Researchers analyzed data from the Mars Express and Mars Reconnaissance Orbiter, finding that thousands of buttes and mesas near Mawrth Vallis, situated at the dichotomy boundary, share a similar height with a nearby higher-elevation plateau, indicating they are remnants of a larger plateau eroded away. This massive erosion suggests an active water cycle early in Mars' history, consistent with the theory of a northern ocean but also potentially caused by other hydrological processes like ice cap melting. The finding offers new clues about early Martian climate and geological evolution, adding to evidence for a past ocean but also raising new questions.