NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The circum-Chryse region as a possible example of a hydrologic cycle on Mars: Geologic observations and theoretical evaluationThe transection and superposition relationships among channels, chaos, surface materials units, and other features in the circum-Chryse region of Mars were used to evaluate relative age relationships and evolution of flood events. Channels and chaos in contact (with one another) were treated as single discrete flood-carved systems. Some outflow channel systems form networks and are inferred to have been created by multiple flood events. Within some outflow channel networks, several separate individual channel systems can be traced to a specific chaos which acted as flood-source area to that specific flood channel. Individual flood-carved systems were related to widespread materials units or other surface features that served as stratigraphic horizons. Chryse outflow channels are inferred to have formed over most of the perceivable history of Mars. Outflow channels are inferred to become younger with increasing proximity to the Chryse basin. In addition, outflow channels closer to the basin show a greater diversity in age. The relationship of subsequent outflow channel sources to the sources of earlier floods is inferred to disfavor episodic flooding due to the progressive tapping of a juvenile near-surface water supply. Instead, we propose the circum-Chryse region as a candidate site of past hydrological recycling. The discharge rates necessary to carve the circum-Chryse outflow channels would have inevitably formed temporary standing bodies of H2O on the Martian surface where the flood-waters stagnated and pooled (the Chryse basin is topographically enclosed). These observations and inferences have led us to formulate and evaluate two hypotheses: (1) large amounts of the sublimated H2O off the Chryse basin flood lakes precipitated (snowed) onto the flood-source highlands and this H2O was incorporated into the near surface, recharging the H2O sources, making possible subsequent deluges; and (2) ponded flood-water in Chryse basin drained back down an anti basinward dipping subsurface layer accessed along the southern edge of the lake, recharging the flood-source aquifers. H2O not redeposited in the flood-source region was largely lost to the hydrologic cycle. This loss progressively lowered the vitality of the cycle, probably by now killing it. Our numerical evaluations indicate that of the two hypotheses we formulated, the groundwater seep cycle seems by far the more viable. Optimally, approx. 3/4 of the original mass of an ice-covered cylindrical lake (albedo 0.5, 1 km deep, 100-km radius, draining along its rim for one quarter of its circumference into substrata with a permeability of 3000 darcies) can be modeled to have moved underground (on timescales of the order of 10(exp 3) years) before the competing mechanisms of sublimation and freeze down choked off further water removal. Once underground, this water can travel distances equal to the separation between Chryse basin and flood-source sites in geologically short (approx. 10(exp 6) year-scale) times. Conversely, we calculate that optimally only approx. 40% of the H2O carried from Chryse can condense at the highlands, and most of the precipitate would either collect at the base of the highlands/lowlands scarp or sublimate at rates greater than it would accumulate over the flood-source sites. Further observations from forthcoming missions may permit the determination of which mechanisms may have operated to recycle the Chryse flood-waters.
Document ID
19980210070
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Moore, Jeffrey M.
(National Academy of Sciences - National Research Council Moffett Field, CA United States)
Clow, Gary D.
(Geological Survey Menlo Park, CA United States)
Davis, Wanda L.
(NASA Ames Research Center Moffett Field, CA United States)
Gulick, Virginia C.
(National Academy of Sciences - National Research Council Moffett Field, CA United States)
Janke, David R.
(Arizona State Univ. Tempe, AZ United States)
McKay, Christopher P.
(NASA Ames Research Center Moffett Field, CA United States)
Stoker, Carol R.
(NASA Ames Research Center Moffett Field, CA United States)
Zent, Aaron P.
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
August 18, 2013
Publication Date
March 25, 1995
Publication Information
Publication: MSATT: Mars Surface and Atmosphere Through Time
Publisher: Americal Geophysical Union
Volume: 100
Issue: E3
Subject Category
Lunar And Planetary Exploration
Report/Patent Number
Paper-94JE02805
Funding Number(s)
PROJECT: RTOP 154-10-80-48
CONTRACT_GRANT: NAGw-1
PROJECT: RTOP 151-01-60-11
PROJECT: RTOP 154-60-80-45
Distribution Limits
Public
Copyright
Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available