RIPPLE-LIKE FEATURES ON MARS, CHARACTERISTICS AND CLASSIFICATION

Ripple-like features on Mars typically occur in patches or fields arranged in remarkably organized patterns extending over hundreds of kilometers. Transverse Aeolian Ridges (TARs) and Plains Ripples are just two examples of these features. On Mars, ripple-like features come in a wide range of morphologies and patterns. Conversely, Earth doesn’t have such complex patterns of ripples or mega-ripples. Introduced terrestrial analogues also couldn’t completely define Martian ripple-like features’ characteristics. The causes of these diversities in Martian ripple-like features is still poorly understood. However, Inconsistencies in the geomorphological definition of these aeolian features in the literature, including the use of the term ‘TARs’, underscores the complexity in the characteristics of these landforms; this supports the need for a robust classification. Defining the differences in morphology and patterns of TARs, Plains Ripples and other types of ripple-like features is needed for understanding their boundary conditions, identifying possible sources and studying their terrestrial analogues. In fact, no study has made a careful survey of their size (geomorphologic parameters) and pattern. In addition, despite the abundance of ripple-like features on Mars, most previous studies examined trending of these features in just one Martian location (Meridiani Planum). The main goal of this study is to make a clear classification for Martian ripple-like features and delineate the geomorphological differences between these classes by using MOC and HiRISE images and HiRISE DTMs and quantifying their characteristics individually and in patterns. This classification will be based on three different sets of quantitative parameters related to their morphometry, pattern and environment. These differences and definitions will be extended and examined in three locations on Mars with different setting, geology and morphology. Finally, apart from exploring an accurate distinction between ripple like features (i.e. TARs and plain ripples), the ultimate result of these analyses would have to be a robust quantitative classification of Martian ripple-like features.