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Geomorphology and Geology of the Southwestern Margaritifer Sinus and Argyre Regions of Mars. Part 2: Crater Size-frequency Distribution Curves and Geomorphic Unit AgesIn assessing the relative ages of the geomorphic/geologic units, crater counts of the entire unit or nearly the entire unit were made and summed in order to get a more accurate value than obtainable by counts of isolated sections of each unit. Cumulative size-frequency counts show some interesting relationships. Most of the units show two distinct crater populations with a flattening out of the distribution curve at and below 10 km diameter craters. Above this crater size the curves for the different units diverge most notably. In general, the variance may reflect the relative ages of these units. At times, however, in the larger crater size range, these curves can overlap and cross on another. Also the error bars at these larger sizes are broader (and thus more suspect), since counts of larger craters show more scatter, whereas the unit areas remain constant. Occasional clusters of relatively large craters within a given unit, particularly one of limited areal extent, can affect the curve so that the unit might seem to be older than units which it overlies or cuts.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Parker, T. J.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Pieri, D. C.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1985
Publication Information
Publication: NASA, Washington Repts. of Planetary Geol. and Geophys. Program, 1984
Subject Category
Lunar And Planetary Exploration
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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