^1,2,3Yuchun Wu,²Nicolas Mangold,^1,3,4Yang Liu,⁵John Carter,¹Xing Wu,^4,6Lu Pan,⁷Qian Huang,^1,2,3Chaolin Zhang,^1,3Keyi Li,⁶Yongliao Zou
Journal of Geophysical Research (Planets)(in Press) Link to Article [https://doi.org/10.1029/2025JE008951]
¹State Key Laboratory of Solar Activity and Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
²Laboratoire de Planétologie et Géosciences, Nantes Université, University Angers, Le Mans Université, CNRS, LPG UMR 6112, Nantes, France
³College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
⁴National Key Laboratory of Deep Space Exploration, Hefei, China
⁵Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS, Orsay, France
⁶School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China
⁷Hubei Subsurface Multi-scale Imaging Key Laboratory, School of Geophysics and Geomatics, China University of Geosciences, Wuhan, China
Published by arrangement with John Wiley & Sons

Tyrrhena Terra, a region located in the cratered highlands between Hellas and Isidis Planitia on Mars, is distinguished by its extensive presence of hydrated minerals. Using 542 hyperspectral images from the Compact Reconnaissance Imaging Spectrometer for Mars, we detected 252 exposures of hydrated minerals. This region is characterized by a widespread distribution of Fe/Mg-smectites/vermiculites and chlorite, with additional detections of Al-phyllosilicates, zeolites, prehnite, hydrated silica, and carbonates. We classified the mineralogical detections in classes of impact crater diameters, locations in craters, and for those
20 km, their relative degradation stages. We found that craters
10 km display a lower mineral diversity than larger ones. In contrast, craters
20 km display a high mineral diversity, especially in central peaks, suggesting a strong influence of hydrothermal processes and deep excavation. Among this diameter range, fresh, young craters exhibit a much higher mineral diversity than degraded, old craters. Fe/Mg-phyllosilicates are dominant in the latter, as well as in sedimentary units of topographically low areas. These results indicate a long-term alteration cycle in the most ancient period, where the initial, diverse hydrated minerals—formed through exhumation and/or hydrothermal circulation within large impacts—were subsequently transformed by surface weathering and/or buried, dissolved, or eroded away by other post-impact processes, then transported and deposited in lowlands by fluvial erosion. Although Tyrrhena Terra is dominated by impact-related hydrated mineral detections, our study shows that the overprint of Noachian age weathering is visible within these detections.