Pits Near Alba Patera
Pits Near Alba Patera
PSP_005334_2170  Science Theme: Hydrothermal Processes
This observation shows pits in Acheron Catena, a chain of circular depressions located southeast of Alba Patera, the widest and flattest volcano on Mars. The layers seen around the pit rims (see subimage, approximately 350 meters across) are likely lava flows from Alba Patera or the nearby Tharsis Mons.

The pits probably formed by collapse into empty space beneath the surface as opposed to being formed by an impactor from space. Some of the pits have large piles of material in their centers. These piles are evidence of collapse of the walls, which may have occurred after the main collapse event that formed each pit. The second pit from the right has an indistinct north rim; it appears that there were at least two collapse events here.

A couple of the pits have oval shaped craters on their walls (see subimage,). The craters were almost certainly circular when they formed, but time and gravity have allowed the deformation of their shape by mass wasting.

Written by: Kelly Kolb  (28 November 2007)
Acquisition date
16 September 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
289.3 km (179.8 miles)

Original image scale range
28.9 cm/pixel (with 1 x 1 binning) so objects ~87 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
62°, with the Sun about 28° above the horizon

Solar longitude
314.6°, Northern Winter

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  310.5°
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