Thursday, 12 November 2015

Northern Martian mid-latitudes: Deuteronilus Mensae

The northern hemisphere elevation dichotomy boundary, between the flat plains in the north and the highlands to the south is where a large number of glacial landforms have been seen.

Here is the area around Deuteronilus Mensae:

Summary of general area, with elevation blended with MOC mosaic, and HRSC tiles overlaid with colour-coded elevation blended with nadir image.
Colour-coded MOLA elevation alone

MOLA elevation, blended with hillshade

h5314 

A crater at 6°W, 38°N, with two Souness GLFs in the crater wall within the HRSC tile h5314.
 
Elevation blended with HRSC nadir image. Souness 1 is the lowest elevation GLF in this part of the northern hemisphere (there is a cluster around 120°E, 40°N that are lower) at a head elevation of -4222m.

The classifier, showing topographic similarity to head and extents of Souness GLFs.
There are several HiRISE images available of this crater, including ESP_019070_2185, ESP_028050_2185, and a 3D anaglyph ESP_034287_2185.


ESP_019070_2185 on the east wall of the crater
ESP_028050_2185
The 3D anaglyph ESP_034287_2185_ESP_035078_2185 covering the area around the central mound and the north wall.

h5285

Showing an area around 16°E, 37°N  within tiles h5321, h5303, h5285, h5267 and h5249. A number of Souness GLFs are evident.



There are two HiRISE 3D anaglyphs overlapping Souness GLFs in this area.
ESP_034972_2175_ESP_034695_2175

ESP_016076_2175_ESP_016221_2175

HiRISE image http://www.uahirise.org/ESP_035618_2175. In finding the link for this I was pleased to find it was made into a 3D anaglyph after the publication of my dissertation.
ESP_036884_2175_ESP_035618_2175

 

h1483

An area around 24°E,  37°N, with a number of Souness GLFs with anaglyphs in the vicinity of, but not overlapping them. At the lower right, there is a high resolution HiRISE DTM available for the area south of Souness 659.



 
3D anaglyph PSP_007795_2175_PSP_009588_2175 to the south-west of Souness 659. This area also has a HiRISE DTM available. Other anaglyphs close to Souness GLFs nearby are ESP_024594_2180, ESP_026994_2180.

h1450

An area at 29°E, 41°N in HRSC tiles h1450 and h1426, containing a number of Souness GLFs.




 
The 3D anaglyph PSP_006806_2215 overlapping Souness 619.

Lyot crater

Lyot crater at 30°E, 50°N is the deepest point in the Northern Hemisphere of Mars with a floor elevation of ~ -7000m. There are no Souness GLFs found in it, although the classifier does pick up substantial areas of topographic similarity to extent and head areas. The has been a study showing evidence for liquid water and fluvial activity in the (relatively) recent past: Dickson et al. 2009.



Here is a series of Google Earth screenshots of part of Lyot, with the CTX imagery mosaic:

From near the centre of the crater, looking S. A large area of dark dunes is seen in the foreground.
Moving south, across some mountains within the crater rising to about ~-4000m.



The southern outer wall perhaps showing some remnants of glacial activity? This would be interesting, because given studies arguing for a microclimate allowing for liquid water at relatively late epochs, perhaps there is a critical elevation below which glaciers were not preserved due to higher ablation, with a thicker atmosphere at the lowest elevations allowing more wind erosion and high temperatures?

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