by bystander » Tue Oct 20, 2015 3:20 pm
Austin S. Guynn and Marjorie A. Chan wrote:Fine-Branched Ridges (ESP_024497_1745) (HiClip)
This image shows numerous branching ridges with various degrees of sinuosity. These branching forms resemble tributaries funneling and draining into larger channel trunks towards the upper portion of the scene.
The raised relief of these branching ridges suggests that these are ancient channels are inverted due to lithification and cementation of the riverbed sediment, which made it more resistant to erosion than the surrounding material. Wind-blown bedforms are abundant and resemble small ridges that are aligned in an approximately north-south direction.
This is a stereo pair with
PSP_007474_1745.
Mike Mellon wrote:A Cone Shaped Hill (ESP_042195_2035) (HiClip)
There are many hills and knobs on Mars that reveal aspects of the local geologic history.
Typically the hills in the relatively-smooth region surrounding this image are flat topped erosional remnants or mesas with irregular or even polyhedral margins. These landforms suggest wide spread erosion of the soft or weakly-cemented sedimentary layers.
This hill stands out because of is circular inverted-cone shape and apparent dark streaks along its flanks visible in lower resolution images.
Close inspection from HiRISE reveals that the fine soils sloping down from the peak are intersected with radiating lines of rock and eroding rubble.
This formation is similar to lava intrusions that form in the core of a volcano. As lava is squeezed up into a central conduit, radiating fractures fill with lava forming rock units called dikes. As the lava cools inside the ground and in the fractures, it forms into a harder rock that is more resistant to erosion. Later, as the surrounding sediments and soils erode, the resistant volcanic rock remains standing to tell a story of what happened underground long ago.
Kirby Runyon wrote:Kasei Valles (ESP_042518_2065) (HiClip)
Kasei Valles is a valley system was likely carved by some combination of flowing water and lava.
In some areas, erosion formed cliffs along the flow path resulting in water or lava falls. The flowing liquid is gone but the channels and ”dry falls” remain.
Since its formation, Kasei Valles has suffered impacts—resulting in craters—and has been mantled in dust, sand, and fine gravel as evidenced by the rippled textures.
This is a stereo pair with
ESP_034329_2065.
Credit: NASA/JPL-Caltech/University of Arizona
<< Previous HiRISE Update[quote="Austin S. Guynn and Marjorie A. Chan"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_024497_1745.jpg[/img3][/float][size=110][b][i][url=http://www.uahirise.org/ESP_024497_1745]Fine-Branched Ridges (ESP_024497_1745)[/url] ([url=https://www.youtube.com/watch?v=qlgBTE3nhAc]HiClip[/url])[/i][/b][/size]
This image shows numerous branching ridges with various degrees of sinuosity. These branching forms resemble tributaries funneling and draining into larger channel trunks towards the upper portion of the scene.
[url=http://static.uahirise.org/images/2015/details/cut/ESP_024497_1745.jpg][b]The raised relief of these branching ridges[/b][/url] suggests that these are ancient channels are inverted due to lithification and cementation of the riverbed sediment, which made it more resistant to erosion than the surrounding material. Wind-blown bedforms are abundant and resemble small ridges that are aligned in an approximately north-south direction.
This is a stereo pair with [url=http://www.uahirise.org/PSP_007474_1745][b]PSP_007474_1745[/b][/url]. [/quote]
[quote="Mike Mellon"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_042195_2035.jpg[/img3][/float][size=110][b][i][url=http://www.uahirise.org/ESP_042195_2035]A Cone Shaped Hill (ESP_042195_2035)[/url] ([url=https://www.youtube.com/watch?v=3h5jaiI_HZM]HiClip[/url])[/i][/b][/size]
There are many hills and knobs on Mars that reveal aspects of the local geologic history.
Typically the hills in the relatively-smooth region surrounding this image are flat topped erosional remnants or mesas with irregular or even polyhedral margins. These landforms suggest wide spread erosion of the soft or weakly-cemented sedimentary layers.
This hill stands out because of is circular inverted-cone shape and apparent dark streaks along its flanks visible in lower resolution images. [url=http://static.uahirise.org/images/2015/details/cut/ESP_042195_2035.jpg][b]Close inspection from HiRISE reveals[/b][/url] that the fine soils sloping down from the peak are intersected with radiating lines of rock and eroding rubble.
This formation is similar to lava intrusions that form in the core of a volcano. As lava is squeezed up into a central conduit, radiating fractures fill with lava forming rock units called dikes. As the lava cools inside the ground and in the fractures, it forms into a harder rock that is more resistant to erosion. Later, as the surrounding sediments and soils erode, the resistant volcanic rock remains standing to tell a story of what happened underground long ago. [/quote]
[quote="Kirby Runyon"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_042518_2065.jpg[/img3][/float][size=110][b][i][url=http://www.uahirise.org/ESP_042518_2065]Kasei Valles (ESP_042518_2065)[/url] ([url=https://www.youtube.com/watch?v=u3Uag7_5upk]HiClip[/url])[/i][/b][/size]
Kasei Valles is a valley system was likely carved by some combination of flowing water and lava. [url=http://static.uahirise.org/images/2015/details/cut/ESP_042518_2065.jpg][b]In some areas[/b][/url], erosion formed cliffs along the flow path resulting in water or lava falls. The flowing liquid is gone but the channels and ”dry falls” remain.
Since its formation, Kasei Valles has suffered impacts—resulting in craters—and has been mantled in dust, sand, and fine gravel as evidenced by the rippled textures.
This is a stereo pair with [url=http://www.uahirise.org/ESP_034329_2065][b]ESP_034329_2065[/b][/url]. [/quote]
[quote="Kirby Runyon"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_042615_1385.jpg[/img3][/float][size=110][b][i][url=http://www.uahirise.org/ESP_042615_1385]Gullies in a Central Pit Crater (ESP_042615_1385)[/url] ([url=https://www.youtube.com/watch?v=TbBIVRg9nYk]HiClip[/url])[/i][/b][/size]
Sometimes a central pit forms inside some Martian craters, especially when there’s substantial ground ice. Such is the case in this observation.
Sometimes what we call “mass wasting” processes (think small avalanches or landslides) occur on the slopes of the central pit. We took this image to search for any recent activity that would [url=http://static.uahirise.org/images/2015/details/cut/ESP_042615_1385.jpg][b]add to or modify previously identified gullies[/b][/url]. [/quote]
[b][i]Credit: NASA/JPL-Caltech/University of Arizona[/i][/b]
[url=http://asterisk.apod.com/viewtopic.php?t=35239][size=85][b][i]<< Previous HiRISE Update[/i][/b][/size][/url]