Friday, 6 November 2015

The Southern Foothills of Tharsis

This will be the last of the southern hemisphere summary plots, covering the area south of the Tharsis bulge and surrounding areas.

It is a large area with relatively small numbers of scattered Souness GLFs, often found in crater walls.

HRSC DTM tiles in area south of Tharsis in western southern mid-latitudes.

Elevation colour ramp used for all HRSC DTM tiles above
MOLA elevation alone.

Elevation colour ramp for MOLA data
Hillshaded MOLA topography.

Below is an close up of a crater in the northern part of tile h2501.
The GLFs in this area, of which four are shown in the images below, are at an elevation of around 2000m above datum, with the crater floor generally around 1000m, and the surrounding plain at about 2500.

A crater found in the H2501 tile of HRSC at 100°W, 46°S.

There are four Souness catalogued objects and the classifier picks out areas with high similarity to the topography of the Souness GLFs (red - head areas, blue - extent areas). The crater walls also show areas of gullies, and an inner depression in the centre.
The north wall of the crater. A region close to the leftmost Souness GLF in this image is covered by HiRISE.

The western wall, containing a Souness GLF and areas of gullies. There is a HiRISE image covering an area near to the Souness GLF in the western wall.

The southern part of the crater

An oblique view of CTX imagery of the north wall of the crater. The red outline denotes HiRiSE coverage.
Looking SW towards the western wall of the crater.

A subpopulation of Souness GLFs at high elevation

This area has some of the highest elevation Souness GLFs there are. All 5 of the GLFs at higher than +6000m fall within HRSC tiles h0266 and h0453.

The Warrego Valles area showing HRSC tiles h0266 and h0453.
Part of h0266 showing 4 Souness GLFs.

The classifier may not be expected to work well, because the objects are outside the elevation range of the rest of the Souness GLFs. It does behave somewhat differently because the 'head' areas are much less prominent.

Part of h0453 showing Souness 844 which is the highest elevation GLF of all. The head area is at an elevation of 7485m.

Classifier output.

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