No CrossRef data available.
Article contents
The Geomorphic Evolution of the Lunar Surface
Published online by Cambridge University Press: 07 February 2017
Abstract
Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
Fundamental parameters of the geomorphology of a lunar surface are (i) the number and size distribution of craters, (ii) the degree of erosion of the craters and (iii) thickness and other characteristics of the regolith. These parameters are not independent of one another; as one changes through time, the other two will also change in a statistically predictable way.
In the continuous degradation sequence, the relationship between the number of craters per unit area and the degree of erosion of the craters is continuous and monotonic. This sequence occurs in areas subjected to intermediate to small impacts, and eroded mainly by the impacts themselves plus other small-scale erosional processes. In areas subjected to large impacts and mare flooding the discontinuous degradation sequence is predominant.
The relationship of the first two parameters, the number of craters and the degree of erosion, with the third parameter, the regolith, is not simple and is not yet understood. It appears, however, that the geomorphological stage is more important than the mare-versus-highland dichotomy of the lunar surface.
The solution of the function relating craters of the continuous degradation sequence with degree of erosion was defined as the geomorphic index of the area. Studies of the geomorphic index of stratigraphic surfaces show that areas covered by considerable ballistic sediments have a geomorphic index which is not a monotonic function of time. On the other hand, areas covered almost exclusively by mare flooding show an index which is a monotonic function of the age of the flooding. As each mare surface shows a considerable range in indices, it is concluded that maria are covered by surfaces formed through a considerable length of time. By using Apollo 11 and 12 radiometric ages it is suggested that the time of mare flooding lasted on the order of one billion (109) years.
The geomorphic index of highland surfaces shows a remarkable degree of order; i.e., the farther an area is inland from the mare shores, the higher will be the index. No explanation is given to this phenomenon, but is suggested that lunar erosion is not just a localized phenomenon centered on the locus of an impact, but has lateral trends of regional dimensions. Electrostatic transportation as suggested by Gold is a possible mechanism.
- Type
- Part II: Scientific Papers
- Information
- Copyright
- Copyright © Reidel 1972
References
Albee, A. L., Burnett, D. S., Chodos, A. A., Eugster, O. J., Huncke, J. C., Papanastassiou, D. A., Pososek, F. A., Price Russ, G. II, Sanz, H. G., Tera, F., and Wasserburg, G. J.: 1970, Science
167, 463.CrossRefGoogle Scholar
Arthur, D. W. G., Agnieray, A P., Horvath, R. A., Wood, C. A., and Chapman, C. R.: 1963, ‘The System of Lunar Craters, Quadrant 1’, Lunar Planet. Lab., Univ. Arizona, Commun. 2, p. 1.Google Scholar
Arthur, D. W. G., Agnieray, A. P., Pellicori, R. H., Wood, C. A., and Weller, T.: 1965, ‘The Systems of Lunar Craters, Quadrant III’, Lunar Planet. Lab., Univ. Arizona, Commun. 3, p. 1.Google Scholar
Arthur, D. W. G., Pellicori, R. H., and Wood, C. A.: 1966, ‘The System of Lunar Craters, Quadrant IV’, Lunar Planet. Lab., Univ. Arizona, Commun. 5, p. 1.Google Scholar
McCauley, J. F.: 1967, in Runcorn, S. K. (Ed.), Mantles of the Earth and Terrestrial Planets, John Wiley & Sons, Inc., New York, p. 431.Google Scholar
Mutch, J. A.: 1970, Geology of the Moon, Princeton University Press, Princeton, U.S.A., 324 pp.Google Scholar
Papanistassiou, D. A. and Wasserburg, G. J.: 1970, Earth Planetary Sci. Letters
8, 269.CrossRefGoogle Scholar
Ronca, L. B.: 1971b, ‘Ages of Lunar Mare Surfaces. The Geological Society of America Bulletin’.CrossRefGoogle Scholar
You have
Access