Detailed mapping of detached plateaus and knobby terrain across the highland/lowland boundary on Mars
The present-day boundary between the cratered highlands and northern lowland plains on Mars represent a major physiographic landform. In some regions there is clear evidence of a southward migration of this boundary. The authors have mapped features which may be relict pieces of highlands; flat-topped, angular mesas which we call detached plateaus, knobby terrain and partial craters to determine where ancient cratered terrain may have been in the past. Most of the detached plateaus and knobby terrain lie along or slightly north of the present-day highland boundary, but significant occurrences are also found at high northern latitudes in several locations. They have also identified, mapped and measured all symmetric knobs visible on the 1:2,000,000 controlled photomosaics with the long dimension greater than or equal to 10 km and classified them by shape. Between +65/sup 0/ and -45/sup 0/ there are 1634 such features, many of which are concentrated along the highland/lowland boundary or around the rims of major impact basins such as Isidis, Argyre and Hellas. The most common shape is elliptical (79%) followed by circular (11%) and triangular or wedge-shaped (6%). Globally, all types share a similar decrease in number with increasing size. Regionally, there are significant differences in the size-frequency distributions that seem to be related to their locations; whether the knobs are associated with impact basin rims, the highland/lowland boundary or volcanic plains. There are similar variations in the shape-size characteristics of the elliptical knobs.
- Research Organization:
- Goddard Space Flight center, Greenbelt, MD (USA)
- OSTI ID:
- 6864005
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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