by bystander » Wed Nov 14, 2012 9:27 pm
HiRISE Science Team wrote:Possible Phyllosilicate Near Margaritifer Chaos (ESP_028288_1720)
According to CRISM multispectral data, the exposures of light-toned materials (
on small hills and between darker dunes) shows a strong iron-magnesium phyllosilicate signatures in this area. Phyllosilicates, or sheet silicates, are an important group of minerals that includes the micas, chlorite, serpentine, talc, and the clay minerals.
The existence of clay minerals is especially interesting on Mars since we want to know under what conditions these minerals formed. Could it have been the presence of water?
This image is a new one for HiRISE, since we have no previous observations of this area. With our camera's resolution and data from CRISM, we might be able to determine if these particular phyllosilicates are actually present here.
HiRISE Science Team wrote:Chutes and Flows (ESP_028321_1785)
In previously images acquired by CTX (Context Camera also on MRO), we see what appears to be the flow of surface material that has traveled up to the rim of a 3-kilometer diameter crater. Some of this surface flow appears to have breached the crater rim and flowed into the crater by way of chutes.
Since HiRISE
has much better resolution than CTX, we might be able to determine if the flow material is preserved within these chutes. This would go a long way to settling the issue of whether the flows consisted of lava or mud. If it were lava, some of it would have solidified in the chutes and remain there today as volcanic rock. If it were mud, there might not be any residual mud within the chutes after the water was lost. Percolation of the water deeper underground and evaporation into the atmosphere would remove much of the mass and cohesion of the mud leaving the chutes largely empty.
The crater rim is also very eroded, and there are numerous slope streaks on the crater walls. Also note the relatively smooth surrounding plain.
Mike Mellon wrote:A Streamlined Island in Athabasca Valles (ESP_028519_1895)
This image completes a mosaic of images covering a collection of streamlined islands in Athabasca Valles. Streamlined islands form by a rapid erosive flow (catastrophic flooding) around an obstacle such as a resistant rock outcrop or surface armored by impact ejecta.
Examination of the margins of the islands can show evidence of terraces as in this image. Each terrace may indicate a different flow event or flood level, and can be used to reconstruct the history of flood events.
Candy Hansen wrote:Only on Mars (ESP_028910_0985)
The South Polar terrain of Mars has a landscape
unlike anywhere on Earth. In this scene groups of radially-organized channels, informally called "spiders" or more formally "araneiform terrain," are visible in rows.
Spiders come in many sizes and are thought to be formed by erosion in the Martian spring. In the wintertime a seasonal polar cap composed of dry ice covers the polar region. In the spring, the gas escaping from under the ice erodes the channels in the surface. As the gas escapes into the atmosphere it deposits the material it is carrying, forming the dark splotches and fans we see in this image.
Credit: NASA/JPL/University of Arizona
<< Previous HiRISE Update[quote="HiRISE Science Team"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_028288_1720.jpg[/img3][/float][url=http://www.uahirise.org/ESP_028288_1720][b][i]Possible Phyllosilicate Near Margaritifer Chaos (ESP_028288_1720)[/i][/b][/url]
According to CRISM multispectral data, the exposures of light-toned materials ([url=http://www.uahirise.org/images/2012/details/cut/ESP_028288_1720.jpg][b]on small hills and between darker dunes[/b][/url]) shows a strong iron-magnesium phyllosilicate signatures in this area. Phyllosilicates, or sheet silicates, are an important group of minerals that includes the micas, chlorite, serpentine, talc, and the clay minerals.
The existence of clay minerals is especially interesting on Mars since we want to know under what conditions these minerals formed. Could it have been the presence of water?
This image is a new one for HiRISE, since we have no previous observations of this area. With our camera's resolution and data from CRISM, we might be able to determine if these particular phyllosilicates are actually present here. [/quote]
[quote="HiRISE Science Team"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_028321_1785.jpg[/img3][/float][url=http://www.uahirise.org/ESP_028321_1785][b][i]Chutes and Flows (ESP_028321_1785)[/i][/b][/url]
In previously images acquired by CTX (Context Camera also on MRO), we see what appears to be the flow of surface material that has traveled up to the rim of a 3-kilometer diameter crater. Some of this surface flow appears to have breached the crater rim and flowed into the crater by way of chutes.
Since HiRISE [url=http://www.uahirise.org/images/2012/details/cut/ESP_028321_1785][b]has much better resolution[/b][/url] than CTX, we might be able to determine if the flow material is preserved within these chutes. This would go a long way to settling the issue of whether the flows consisted of lava or mud. If it were lava, some of it would have solidified in the chutes and remain there today as volcanic rock. If it were mud, there might not be any residual mud within the chutes after the water was lost. Percolation of the water deeper underground and evaporation into the atmosphere would remove much of the mass and cohesion of the mud leaving the chutes largely empty.
The crater rim is also very eroded, and there are numerous slope streaks on the crater walls. Also note the relatively smooth surrounding plain. [/quote]
[quote="Mike Mellon"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_028519_1895.jpg[/img3][/float][url=http://www.uahirise.org/ESP_028519_1895][b][i]A Streamlined Island in Athabasca Valles (ESP_028519_1895)[/i][/b][/url]
This image completes a mosaic of images covering a collection of streamlined islands in Athabasca Valles. Streamlined islands form by a rapid erosive flow (catastrophic flooding) around an obstacle such as a resistant rock outcrop or surface armored by impact ejecta.
Examination of the margins of the islands can show evidence of terraces as in this image. Each terrace may indicate a different flow event or flood level, and can be used to reconstruct the history of flood events. [/quote]
[quote="Candy Hansen"][float=left][img3=""]http://www.uahirise.org/images/wallpaper/800/ESP_028910_0985.jpg[/img3][/float][url=http://www.uahirise.org/ESP_028910_0985][b][i]Only on Mars (ESP_028910_0985)[/i][/b][/url]
The South Polar terrain of Mars has a landscape [url=http://www.uahirise.org/images/2012/details/cut/ESP_028910_0985.jpg][b]unlike anywhere on Earth[/b][/url]. In this scene groups of radially-organized channels, informally called "spiders" or more formally "araneiform terrain," are visible in rows.
Spiders come in many sizes and are thought to be formed by erosion in the Martian spring. In the wintertime a seasonal polar cap composed of dry ice covers the polar region. In the spring, the gas escaping from under the ice erodes the channels in the surface. As the gas escapes into the atmosphere it deposits the material it is carrying, forming the dark splotches and fans we see in this image. [/quote]
[b][i]Credit: NASA/JPL/University of Arizona[/i][/b]
[url=http://asterisk.apod.com/viewtopic.php?t=29965][size=85][b][i]<< Previous HiRISE Update[/i][/b][/size][/url]