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Earth-like aqueous debris-flow activity on Mars at high orbital obliquity in the last million years.

de Haas T, Hauber E, Conway SJ, van Steijn H, Johnsson A, Kleinhans MG - Nat Commun (2015)

Bottom Line: This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems.Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars.Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Geosciences, Universiteit Utrecht, Heidelberglaan 2, 3584 CS, Utrecht, The Netherlands.

ABSTRACT
Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars. Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

No MeSH data available.


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Debris-flow return periods and size in Istok crater.(a) Cumulative frequency distribution of lobe volume. The minimum, maximum and intermediate estimates are based on a triangular, rectangular and trapezoidal-shaped lobe model, respectively (Supplementary Fig. 2). (b) Cumulative frequency distribution of levee volume, estimated by assuming paired levees of half the bajada length (900 m; 800–1,100 m range). The minimum estimate is based on triangular-shaped paired levees of 400 m long, the maximum estimate on rectangular-shaped paired levees of 550 m long, and the intermediate estimate on trapezoidal-shaped levees of 450 m long. (c) Cumulative frequency distribution of total debris-flow volume (lobe and levee volume combined). (d) Obliquity in the last Myr on Mars18, and potential thresholds for melting on mid-latitude pole-facing crater walls. (e) Debris-flow return periods on the bajada and per catchment. The intermediate estimate (thick line) is calculated from the intermediate-estimate debris-flow size and best-estimate catchment size. The minimum and maximum estimates are calculated from the largest debris-flow size and smallest catchment volume and the smallest debris-flow size and maximum catchment volume, respectively. See Supplementary Tables 1–5 for raw data.
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f2: Debris-flow return periods and size in Istok crater.(a) Cumulative frequency distribution of lobe volume. The minimum, maximum and intermediate estimates are based on a triangular, rectangular and trapezoidal-shaped lobe model, respectively (Supplementary Fig. 2). (b) Cumulative frequency distribution of levee volume, estimated by assuming paired levees of half the bajada length (900 m; 800–1,100 m range). The minimum estimate is based on triangular-shaped paired levees of 400 m long, the maximum estimate on rectangular-shaped paired levees of 550 m long, and the intermediate estimate on trapezoidal-shaped levees of 450 m long. (c) Cumulative frequency distribution of total debris-flow volume (lobe and levee volume combined). (d) Obliquity in the last Myr on Mars18, and potential thresholds for melting on mid-latitude pole-facing crater walls. (e) Debris-flow return periods on the bajada and per catchment. The intermediate estimate (thick line) is calculated from the intermediate-estimate debris-flow size and best-estimate catchment size. The minimum and maximum estimates are calculated from the largest debris-flow size and smallest catchment volume and the smallest debris-flow size and maximum catchment volume, respectively. See Supplementary Tables 1–5 for raw data.

Mentions: Debris flows are high-concentration mixtures of solid particles and water that move as a single-phase high-density flow. Non-cohesive debris flows contain ∼20–60% water by volume232425. They form deposits with paired levees and distinct depositional lobes that often incorporate large boulders. We use the distinct morphology of these deposits to estimate individual debris-flow volumes from a High-Resolution Imaging Science Experiment (HiRISE) Digital Elevation Model (DEM) with a sampling distance of 1 m. Estimated individual debris-flow volumes roughly range from 400 to 5,100 m3 (Fig. 2a–c; Table 1) and are similar to those in unconfined terrestrial debris-flow systems262728 (Fig. 3).


Earth-like aqueous debris-flow activity on Mars at high orbital obliquity in the last million years.

de Haas T, Hauber E, Conway SJ, van Steijn H, Johnsson A, Kleinhans MG - Nat Commun (2015)

Debris-flow return periods and size in Istok crater.(a) Cumulative frequency distribution of lobe volume. The minimum, maximum and intermediate estimates are based on a triangular, rectangular and trapezoidal-shaped lobe model, respectively (Supplementary Fig. 2). (b) Cumulative frequency distribution of levee volume, estimated by assuming paired levees of half the bajada length (900 m; 800–1,100 m range). The minimum estimate is based on triangular-shaped paired levees of 400 m long, the maximum estimate on rectangular-shaped paired levees of 550 m long, and the intermediate estimate on trapezoidal-shaped levees of 450 m long. (c) Cumulative frequency distribution of total debris-flow volume (lobe and levee volume combined). (d) Obliquity in the last Myr on Mars18, and potential thresholds for melting on mid-latitude pole-facing crater walls. (e) Debris-flow return periods on the bajada and per catchment. The intermediate estimate (thick line) is calculated from the intermediate-estimate debris-flow size and best-estimate catchment size. The minimum and maximum estimates are calculated from the largest debris-flow size and smallest catchment volume and the smallest debris-flow size and maximum catchment volume, respectively. See Supplementary Tables 1–5 for raw data.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557294&req=5

f2: Debris-flow return periods and size in Istok crater.(a) Cumulative frequency distribution of lobe volume. The minimum, maximum and intermediate estimates are based on a triangular, rectangular and trapezoidal-shaped lobe model, respectively (Supplementary Fig. 2). (b) Cumulative frequency distribution of levee volume, estimated by assuming paired levees of half the bajada length (900 m; 800–1,100 m range). The minimum estimate is based on triangular-shaped paired levees of 400 m long, the maximum estimate on rectangular-shaped paired levees of 550 m long, and the intermediate estimate on trapezoidal-shaped levees of 450 m long. (c) Cumulative frequency distribution of total debris-flow volume (lobe and levee volume combined). (d) Obliquity in the last Myr on Mars18, and potential thresholds for melting on mid-latitude pole-facing crater walls. (e) Debris-flow return periods on the bajada and per catchment. The intermediate estimate (thick line) is calculated from the intermediate-estimate debris-flow size and best-estimate catchment size. The minimum and maximum estimates are calculated from the largest debris-flow size and smallest catchment volume and the smallest debris-flow size and maximum catchment volume, respectively. See Supplementary Tables 1–5 for raw data.
Mentions: Debris flows are high-concentration mixtures of solid particles and water that move as a single-phase high-density flow. Non-cohesive debris flows contain ∼20–60% water by volume232425. They form deposits with paired levees and distinct depositional lobes that often incorporate large boulders. We use the distinct morphology of these deposits to estimate individual debris-flow volumes from a High-Resolution Imaging Science Experiment (HiRISE) Digital Elevation Model (DEM) with a sampling distance of 1 m. Estimated individual debris-flow volumes roughly range from 400 to 5,100 m3 (Fig. 2a–c; Table 1) and are similar to those in unconfined terrestrial debris-flow systems262728 (Fig. 3).

Bottom Line: This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems.Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars.Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Geosciences, Universiteit Utrecht, Heidelberglaan 2, 3584 CS, Utrecht, The Netherlands.

ABSTRACT
Liquid water is currently extremely rare on Mars, but was more abundant during periods of high obliquity in the last few millions of years. This is testified by the widespread occurrence of mid-latitude gullies: small catchment-fan systems. However, there are no direct estimates of the amount and frequency of liquid water generation during these periods. Here we determine debris-flow size, frequency and associated water volumes in Istok crater, and show that debris flows occurred at Earth-like frequencies during high-obliquity periods in the last million years on Mars. Results further imply that local accumulations of snow/ice within gullies were much more voluminous than currently predicted; melting must have yielded centimetres of liquid water in catchments; and recent aqueous activity in some mid-latitude craters was much more frequent than previously anticipated.

No MeSH data available.


Related in: MedlinePlus