Friday, 13 November 2015

Nilosyrtis Mensae

Continuing the exploration of the northern hemisphere elevation dichotomy boundary eastward, the Nilosyrtis Mensae area is also rich in Souness glacier-like forms:

HRSC DTMs blended with nadir image.

This is the elevation colour ramp used for all HRSC DTMs in this region.

MOLA elevation.

MOLA elevation blended with hillshade.

Auqukuh Vallis (word for 'Mars' in Quechua)

The Auqukuh Vallis system shows some striking examples of GLFs, and is highly favoured by the Bayesian classifier:

HRSC DTM (tile h1446 at 61°E, 31°N) blended with nadir image. Two Souness GLFs are found within this area, including HiRISE anaglyph coverage of the terminus of S312 (PSP_003482_2115).

The nadir image alone.

Nadir image with classifier for head (red) and extent (blue) areas overplotted.

Another part of the Auqukuh Vallis system at 62°E, 32°N:

Five Souness GLFs are shown in this region, with HRSC DTMs of h1446 and h5173 overlaid on nadir images.

Nadir image alone

With classifier overplotted.
A curious feature at 62.5°E, 32.5°N.

Eastern Nilosyrtis

Around 68°-75°E,  28°-34°N:
HRSC DTM tiles (h1391, h5378, h5360, h5342, h5324, h5306) blended with nadir image.
Nadir images only.

Nadir images with classifier overplotted.
The HiRISE anaglyphs ESP_013160_2135ESP_020597_2135 and ESP_014307_2130 are in the vicinity of, but do not overlap Souness GLFs. 

Closeup of part of tile h5342:
Many Souness GLFs are to be found in this area around 73°E, 30°N.

The classifier picks out areas of the south side of the mesa which do not have Souness GLFs catalogued. Is it possible that glaciers in south facing areas at this relatively low latitude for Souness GLFs were ablated more readily?
Closeup of part of tile h5306 around 75°E, 30°N:

Again the 2 Souness catalogued GLFs are found on the northern side of the mesa only.

HiRISE 3D anaglyph ESP_027823_2100 showing S204.

Close up of h5234/h5306, showing an area further south at 28-29°N:
The southern valleys below 28°N have no Souness catalogued GLFs. The set around 74°E, 28.5°N are the southernmost Souness GLFs in the entire northern hemisphere, except S201 at 77.15°E, 27.78°N at two others in crater Lockyer at 160°E. 27.5°N. 
Nadir images only
Nadir images with classifier.

A closer view. The size of the alcoves suggests that the GLFs here may be the remnants of larger objects that have ablated.

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