Possible evidence for on-going volcanism on Mars as suggested by thin, elliptical sheets of low-albedo particulate material around pits and fissures close to Cerberus Fossae

• Published in: Earth, moon, and planets moon, and planets, 2007-10, Vol.101 (1-2), p.1-16
• Main Authors: Roberts, Gerald Patrick, Crawford, Ian A, Peacock, David, Vetterlein, Joyce, Parfitt, Elisabeth, Bishop, Louise
• Format: Article
• Language: English
• Subjects: Albedo; Aspect ratio; Craters; Ellipses; Geology; Halos; Lava; Lava flows; Mars; Mars orbiter camera; Mars orbiters; Mars volcanoes; Pits; Precipitates; Sediment deposits; Thermal emission; Thermal imaging; Volcanic activity; Volcanic deposits; Volcanic eruption effects; Volcanic eruptions; Volcanoes
• ISSN: 0167-9295; 1573-0794
• DOI: 10.1007/s11038-007-9140-z

We describe 100–200 metre-sized low-albedo haloes from Mars Orbiter Camera (MOC) images, located around sunken pits in the vicinity of Cerberus Fossae, Mars, a fissure-vent system that has been suggested to have been volcanically active within the last few million years. Two types of pit have been identified: (1) lenticular/elongate pits located on the floors of fissures/graben, some of which lead to the summit of a volcano; (2) sub-circular pits, lacking the raised rims expected of impact craters, located either within small lava flows, along fissures, or on flat, cratered plains. The low-albedo haloes encircle the pits, and are in places asymmetric in plan-view, exhibiting almost perfect elliptical outlines with low-aspect ratios, and lightening in appearance towards the margins of the ellipses. Thermal Emission Imaging System (THEMIS) images suggest the haloes are dark particulate deposits. These deposits bury impact craters to a depth of less than a few decimetres. We argue that the elliptical haloes may be mineral precipitates and/or particulate deposits from ballistic volcanic eruptions that have been disrupted by the wind. They are likely be extremely young because