The circum-Chryse region as a possible example of a hydrologic cycle on Mars: Geologic observations and theoretical evaluation

摘要: The transection and superposition relationships among channels, chaos, surface materials units, other features in the circum-Chryse region of Mars were used to evaluate relative age evolution flood events. Channels chaos contact (with one another) treated as single discrete flood-carved systems. Some outflow channel systems form networks are inferred have been created by multiple Within some networks, several separate individual can be traced a specific which acted flood-source area that channel. Individual related widespread units or served stratigraphic horizons. Chryse channels formed over most perceivable history Mars. Outflow become younger with increasing proximity basin. In addition, closer basin show greater diversity age. relationship subsequent sources earlier floods is disfavor episodic flooding due progressive tapping juvenile near-surface water supply. Instead, we propose candidate site past hydrological recycling. discharge rates necessary carve would inevitably temporary standing bodies H2O on Martian where flood-waters stagnated pooled (the topographically enclosed). These observations inferences led us formulate two hypotheses: (1) large amounts sublimated off lakes precipitated (snowed) onto highlands this was incorporated into near surface, recharging sources, making possible deluges; (2) ponded flood-water drained back down an anti basinward dipping subsurface layer accessed long southern edge lake, aquifers. not redeposited largely lost hydrologic cycle. This loss progressively lowered vitality cycle, probably now killing it. Our numerical evaluations indicate hypotheses formulated, groundwater seep cycle seems far more viable. Optimally, approximately 3/4 original mass ice-covered cylindrical lake (albedo 0.5, 1 km deep, 100-km radius, draining along its rim for quarter circumference substrata permeability 3000 darcies) modeled moved underground (on timescales order 10(3) years) before competing mechanisms sublimation freeze choked further removal. Once underground, travel distances equal separation between sites geologically short (approximately 10(6) year-scale) times. Conversely, calculate optimally only 40% carried from condense at highlands, precipitate either collect base highlands/lowlands scarp sublimate than it accumulate sites. Further forthcoming missions may permit determination operated recycle flood-waters.