Tag Archives: fluvial channels

New geologic map details Reull, Waikato valleys

A new geologic map of part of the ancient Martian highlands produced by Scott C. Mest and David A. Crown of the Planetary Science Institute provides new insights into the planet’s history of water modifying the surface. “This map depicts … Continue reading

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THEMIS: Kasei Valles islands

THEMIS Image of the Day, June 6, 2014. There are several streamlined islands in this VIS image of Kasei Valles. This image is located near the region where Kasei Valles empties into Chryse Planitia. More THEMIS Images of the Day … Continue reading

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Mars air has been cold, thin for 3.6 billion years

The atmosphere of Mars today, 95% carbon dioxide, is cold and thin, with less than 1% of Earth’s surface pressure. Yet long ago, it must have been dense enough to allow rivers and streams to flow in many areas of … Continue reading

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HiRISE image: sinuous ridges and meanders

These ridges are thought to be old river channels, but wind erosion has created inverted topography. What was low (the channel bottoms) was more resistant to erosion, so now it is relatively high. In a closeup image, we see a … Continue reading

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Well-rounded pebbles in Gale Crater’s rocks point to longtime stream flow

Mars Science Laboratory rover Curiosity landed in Gale Crater at a feature called Bradbury Rise, which lies near the far end of the Peace Vallis alluvial fan. The fan is a broad, flat deposit of sand, gravel, and pebbles washed … Continue reading

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Aeolis Serpens, Mars’ longest sinuous ridge, is an ancient riverbed

A linear ridge that winds for more than 200 kilometers (120 miles) through part of South Australia was a river channel roughly 10 million years ago. After the paleoriver stopped flowing, silica-rich groundwater seeped into the riverbed, cementing its sediments.

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‘Faint young Sun paradox’ a problem for Mars (and Earth, too)

Astronomers say that billions of years ago when the Sun was young, it shone with only 70 percent its current brightness, notes Robert Craddock (Smithsonian Institution). If that were true of today’s Sun,

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