Starship Asterisk*

John Grant wrote:

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Near the Mouth of Morava Valles (ESP_026007_1640)

Morava Valles drained Ladon Basin and discharged towards the large regions of chaotic terrain near the head of Ares Valles.

Because the valley emerges full bore from Ladon Basin (much like the Niagara river emerges from Lake Erie on the Earth), it has been hypothesized that it was formed when a lake overflowed the basin.

There are numerous valleys, including the large Ladon Valles, that end along the margin of Ladon Basin. Some of the outcrops visible in this image and elsewhere in the basin show evidence of layering due to deposition of sediments.

Comparison of the nature and extent of layers exposed here and elsewhere around Ladon basin should help to constrain their origin, by water flow or other processes.

Alfred McEwen wrote:

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Landforms Near Grota Valles (ESP_026356_1960)

The landforms in this observation are quite diverse, with a segment of the Cerberus Fossae (a deep trough extending east-west) and surrounding terrain that has been eroded by some fluid, either water or lava.

There are many boulders in places, either on steep slopes or excavated by impact craters. The high hills are islands of older terrain surrounded by younger lavas.

Be sure to check out the stereo anaglyph.

This is a stereo pair with ESP_026712_1960.

Laszlo Kestay wrote:

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Streamlined Hills in Elysium Planitia (ESP_026435_1960)

This observation was taken to investigate the topography of hills that were eroded by floods of water or lava. In many locations near here it is clear that the last fluid to flow through the region was lava.

Clear margins of lava flows are visible as well as lava textures on the channel floor. In this location, the cover of wind-blown sand and the effect of many small impact craters has erased such obvious indicators of lava. This is likely because the lava coating is thin and can be easily erased.

However, it is also possible that no lava passed through this location. Further investigation of these data should help us better understand the role of water and lava in changing the Martian landscape.

This is a stereo pair with ESP_025802_1960.

Cathy Weitz wrote:

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Different Materials Exposed along a Wallrock Slope in Coprates Chasma (ESP_027063_1655)

This image shows several kilometers of topography exposed along the wallrock within Coprates Chasma. Higher topography is towards the bottom of the image while the floor of Coprates Chasma is visible at the top of the image.

There are patches of brighter materials exposed within the wallrock and along the chasma floor. The bright massive rocks exposed in the wallrock likely represent weathered rocks that have altered to this brighter material.

Lower down the wallrock and along the chasma floor, the brighter material appears layered and could represent sediments deposited within the chasma when water or ice may have existed here. The image also shows finer material composed of eroded wallrock and eolian debris that is mass wasting downslope.