Is the Gordii Dorsum escarpment on Mars an exhumed transcurrent fault?

Abstract

Investigators of deformation features on the surface of Mars have generally concluded that fault zones with major horizontal displacements do not occur or have not been preserved^1–5. Here we present evidence from high-resolution Viking imagery for an array of structures along the Gordii Dorsum escarpment which suggest that it is a left-lateral strike-slip fault zone of lithospheric proportion. The escarpment is one of an array of subparallel ridges^6,7 preserved in an equatorial region to the west of Tharsis Montes. The region is of transitional character between the youthful ('Amazonian' age) cover of the Amazonia Planitia to the north and older ('Noachian' age) intensely cratered surfaces of the Highlands to the south. Relations between these ridges and the Gordii Dorsum suggest that the ridges are exhumed ancient fault zones. These features imply that Mars, like the Earth today, may have had in its early stages a more dynamic tectonic style of planetary evolution.