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The MOLA Topographic signature at the crustal dichotomy boundary zone on Mars
Author(s) -
Frey Herbert,
Sakimoto Susan E.,
Roark James
Publication year - 1998
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 - 10.1029/1998gl900095
Subject(s) - geology , terrain , transition zone , mars exploration program , elevation (ballistics) , hiatus , boundary (topology) , geomorphology , paleontology , geophysics , geography , geometry , astrobiology , mathematical analysis , physics , mathematics , cartography
MOLA data collected during the aerobraking hiatus provide good longitudinal sampling of the crustal dichotomy boundary zone in eastern Mars and reveal a significant topographic signature associated with the transition from cratered highlands to lowland plains. Total relief between the two major units is always >2.5 km and sometimes >6 km; median elevation differences are about 4 km. Regional slopes are very low (<0.02°) in both cratered terrain south and in lowland plains north of the boundary. Within the transition zone where cratered terrain changes to detached plateaus, mesas and knobby terrain, slopes are 50–100 times steeper and over a few hundred kilometers average about 1°. The topographic signature of the boundary zone is best described as a 2–4 km step function between two nearly flat surfaces, similar in slope and amplitude to some terrestrial passive margins. This supports previous conclusions of a significant difference in crustal properties (thickness, composition, or both) between the lowland plains and cratered terrain, and suggests this difference occurs over a relatively short distance of a few to several hundred kilometers.