The narrow angle MOC images from the Mars Global Surveyor (MGS) show dozens of examples of dark streaks on Martian hillsides that may be indicative of fluid flow. In many cases multiple streaks seem to initiate from a narrow layer near the tops of steep slopes. They appear from these layers as narrow features that quickly broaden and then either remain the same width downhill or narrow and disappear. The largest streak observed to date is approximately 2 km in length and 100 m in width. MOLA data is not yet available to determine the slope down the length of the streaks. The lack of variation in brightness downhill and across the streaks shows that the formation of each streak occurred quickly. The streaks are widely distributed globally, but seem to be confined to layered materials. The streaks' characteristics show not only that the material forming them moved rapidly downslope but also that the streak material originated within the nearby bedrock. Change in brightness from one streak to another provides relative streak ages, assuming that dust infall causes an increase in streak albedo. The dark streaks are caused by a process that appears similar to fluid flow at the resolution of the MOC images. Possible causes of the streaks are water flow, lava flow, and debris flow. Our results are not yet conclusive as to the origins of the dark streaks, but we narrow the range of possible formation processes.
AAS/Division for Planetary Sciences Meeting Abstracts #30
- Pub Date:
- September 1998