Early Mars: The inextricable link between internal and external influences on valley network formation
Year: 1993
Type: article
Abstract: The conditions under which the valley networks on the ancient cratered terrain on Mars formed are still highly debated within the scientific community. While liquid water was almost certainly involved, the exact mechanism of formation is uncertain. The networks most resemble terrestrial sapping channels, although some systems exhibit a runoff-dominated morphology. The major question in the formation of these networks is what, if anything, do they imply about early Martian climate? There are typically two major theories advanced to explain the presence of these networks. The first is that higher internal regolith temperatures, associated with a much higher heat flow 3.8 b.y. ago, would cause ground water to be closer to the surface than at present. Just how close to the surface ground water would have to exist in order to form these valley networks has recently been questioned. The second major theory is that early Mars had a much thicker atmosphere than at present, and an enhanced atmospheric greenhouse may have increased surface temperatures to near the freezing point of water. While recent calculations indicate that CO2 alone could not have produced the needed warming, the presence of other greenhouse gases may have contributed to surface warming.
Authors: S. E. Postawko, F. P. Fanale
Institutions: University of Oklahoma, University of Hawaii System
Language: English
Subfield: Space and Planetary Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
OpenAlex ID: W1482688855