Constraints on early events in martian history as derived from the cratering record

Barlow, Nadine G. (1990) Constraints on early events in martian history as derived from the cratering record. Journal of Geophysical Research, 95 (B9). pp. 14191-14201. ISSN 0148-0227

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Abstract

The shapes and densities of crater size-frequency distribution curves are used to constrain two major events early in Martian history: termination of high obliteration rates and viability of the multiple impact origin of the crustal dichotomy. Distribution curves of fresh craters superposed on uplands, intercrater plains, and ridged plains display shapes and densities indicative of formation prior to the end of heavy bombardment. This observation correlates with other geologic evidence, suggesting a major change in the erosional regime following the last major basin size impact (i.e., Argrye). In addition, the multisloped nature of the curves supports the idea that the downturn in the crater size-frequency distribution curves reflects the size-frequency distribution of the impactors rather than being the result of erosion. The crustal dichotomy formed prior to the heavy bombardment intermediate epoch based on distribution curves of knobby terrain; if the dichotomy resulted from a single gigantic impact, this observation places constraints on when this event happened. An alternate theory for dichotomy formation, the multiple-impact basin idea, is questioned: since distribution curves of large basins as well as heavy bombardment era units are not represented by a −3 differential power law function, this study finds fewer basins missing on Mars compare to the Moon and Mercury than previously reported. The area covered by these missing basins is less than that covered the northern plains.

Item Type:	Article
Publisher’s Statement:	Copyright 1990 by the American Geophysical Union.
ID number or DOI:	10.1029/JB095iB09p14191
Keywords:	cratering record, Mars, impact, Martian history, size-frequency distribution,
Subjects:	Q Science > QB Astronomy
NAU Depositing Author Academic Status:	Faculty/Staff
Department/Unit:	College of Engineering, Forestry, and Natural Science > Physics and Astronomy
Date Deposited:	01 May 2017 20:57
URI:	http://openknowledge.nau.edu/id/eprint/2596

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