Large-diameter Visible and Buried Impact Basins on Mars: Implications for Age of the Highlands and (buried) Lowlands and Turn-off of the Global Magnetc Field
نویسنده
چکیده
The global populations of visible and buried impact basins > 200 km diameter revealed by high resolution gridded MOLA indicate: (a) a small (~10) number of very large basins (D=1300-3000km), most of which have remained visible over martian history; (b) a much larger population of smaller basins (D=200-800 km) with many more buried than visible (on images); (c) a depletion of visible basins at intermediate diameters which may be a signature of some global-scale event (formation of the lowlands? origin of Tharsis?); and (d) a crater retention age for the buried lowlands greater than that of the visible highlands but less than that of the total (visible + buried) highlands. Crustal magnetic anomalies are generally not present in the interiors of the largest basins with two exceptions: these two (which appear to be the oldest) may predate the demise of the global magnetic field.
منابع مشابه
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