Assessing possible typographic errors in Souness catalog

26 Dec 2015 - MawKernewek

In the Souness et al. 2012 paper, a catalog is presented with the various glacier-like-forms identified.

In my analysis, I assume a constant channel width, which is not always a good assumption, and in a few cases, there are duplicates, or what appears to be a possible typographic error. There are only a few out of the 1309 which are likely to be affected.

I have identified some of these in the spreadsheet at this link.

I show the count of Souness GLFs by the regions I used earlier:

Filtergraph link: filtergraph.com/4134840

There are only relatively few that look like they have a typographical error, for example Souness 359, and Souness 1300:

Red dot shows 'head', white 'centre' and dark blue 'terminus'

S1117 and S1301 are duplicates and S1300 appears to contain a typo

I decided to go through systematically, and look at Souness objects that either looked odd in shape visually, or had a distance between the 'centre' recorded by Souness and the middle of the channel that was more than the channel width.

I below detail the individual Souness objects where there is some kind of query, either being a duplicate or centre out of the mid-channel. In Google Earth, I show heads in blue, termini in yellow, the 'centre' with a snowflake, and left and right mid-channel in magenta and green.

Overall, I don't think this on its own will have made a lot of difference to the classifier, since any DEM segments that overlap the extent would be chosen for the input, and a little more conservative 'extent' for those Souness GLFs that currently include non-glacial terrain would not likely make a decisive difference.

Northern Hemisphere

North of Olympus Mons

See also previous post.

In this area, Souness objects 87, 87, 96 and 108 stand out as odd-shaped.

Location, with the four Souness objects noted highlighted in yellow.

Souness 87 and 88 overlap significantly near the edge of h0037. Souness 91 and 92 are also visible.

Oblique view in Google Earth showing S87, 88, 91 and 92.

Souness 96 starts outside the HRSC tile h0037's area of coverage and joins what looks like a larger valley fill glacial form. The crater also appears to have glacial features infilling it, that are not catalogued by Souness.

Souness 96 looking west with CTX imagery in Google Earth.

Looking down on S96 with CTX imagery. There are other glacial like forms not catalogued by Souness since his intention was to catalogue analogues of valley-glaciers on Earth. In this area of Mars, recent (last few Myr) glacial activity is believed to be superimposed on an older landscape of the larger topographic forms.

S108 is outside any HRSC DTM tile.

The same area, in Google Earth. Note the slope liniae in the crater at lower-right. These may be the result of current episodic brine flows.

Zooming in on S108, a slope line is seen on the slope constraining it topographically.

Mareotis Fossae area

Deuteronilus Mensae

See also previous post.

In this area S6, 590, 617, 618, 634, 693, 708, 720, and 724 either have a markedly off-centre 'centre' or are duplicates.

Souness 6. 30°N, 11°W in HRSC tile h1498.

Souness 6 CTX images.

The duplicated Souness objects S567/578 and S566/577 are shown to the right above.

Souness 590 among several objects not covered by any HRSC DTM.

The same GLFs as the previous image, showing CTX images via Google Earth. Perhaps there has been several glacial epochs in the 'recent' times of the last few Myr that have been superimposed on the longer-term formed topographic channel?