Morphologic characteristics of volcanic and sedimentary sequences on Mars

This paper presents morphometric parameters of Martian layered sequences of different origin that outcrop in the scarps and crater walls, which form natural geologic profiles. The objective of this study was to develop quantitative criteria that would allow distinguishing layers of volcanic and, presumably, sedimentary origin. As a result of measurements of large numbers of layers on images with the highest resolution (HiRISE camera, spatial resolution ∼0.25 m/px) it was established that the combination of total sinuosity and the slope of the spectrum of high-frequency sinuosity generally allow us to differentiate between layered sequences of different origin. For the majority of measured volcanic layers, the total sinuosity values exceed 1.3, and the slope of the power function approximating the sinuosity spectrum exceeds 0.015. The corresponding values are lower for layers of nonvolcanic origin. However, in some cases, the stratified rocks demonstrate such significant variations in these parameters (e.g., layered deposits on the bottom of the Galle crater), that it makes the genetic identification of these layers impossible using the formal criteria. A more robust validation of the genesis of layered sequences requires an integrated approach that includes both the morphometric parameters, and the qualitative criteria and the description and characteristics of the geological situation in a given exposure.