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Evidence for rapid topographic evolution and crater degradation on Mercury from simple crater morphometry
Author(s) -
Fassett Caleb I.,
Crowley Malinda C.,
Leight Clarissa,
Dyar M. Darby,
Minton David A.,
Hirabayashi Masatoshi,
Thomson Bradley J.,
Watters Wesley A.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl073769
Subject(s) - impact crater , geology , mercury (programming language) , landform , astrobiology , geomorphology , mineralogy , physics , computer science , programming language
Examining the topography of impact craters and their evolution with time is useful for assessing how fast planetary surfaces evolve. Here, new measurements of depth/diameter ( d / D ) ratios for 204 craters of 2.5 to 5 km in diameter superposed on Mercury's smooth plains are reported. The median d / D is 0.13, much lower than expected for newly formed simple craters (~0.21). In comparison, lunar craters that postdate the maria are much less modified, and the median crater in the same size range has a d / D ratio that is nearly indistinguishable from the fresh value. This difference in crater degradation is remarkable given that Mercury's smooth plains and the lunar maria likely have ages that are comparable, if not identical. Applying a topographic diffusion model, these results imply that crater degradation is faster by a factor of approximately two on Mercury than on the Moon, suggesting more rapid landform evolution on Mercury at all scales.