OBJECTIVE GEOLOGICAL AND GEOMORPHOLOGICAL MAPPING OF MARTIAN SEDIMENTARY DEPOSITS: AN EXAMPLE FROM THE SOUTHEASTERN MARGIN OF HOLDEN CRATER

Sedimentary environments and associated deposits and morphologies are among the most important geologic records present on Mars’ surface, due to their implication with past climatic conditions and their variations through geological times. Fortunately, the constant improvement of available datasets favors ever more detailed analysis and to edit topical maps with an approach somewhat akin to the relatively ‘objective’ geological mapping approach on Earth. In particular, the planetary mapping process is more significant in small areas (e.g., basins) where data coverage is extremely dense and has high-resolution. In these conditions, deposits are distinguished based on their objectively defined characteristics apart from the genetic interpretation provided by the morphology. A clear distinction between descriptive (objective) and interpretative (subjective) units is specifically useful when geomorphological interpretation is particularly controversial. Unlike on Earth, sedimentary systems are well-preserved down to the deep stratigraphic succession, making stratigraphy a pivotal concept that needs to be included within map information and a prerequisite to a well constrained interpretation of the Martian geological environments. Within the Europlanet H2024-GMAP (Geologic MApping of Planetary bodies) infrastructure, we have attempted to apply all these different but complementary concepts and information in a single cartographic product of southeastern Holden crater. For such an aim we have borrowed, where possible, the Earth symbols designed for the Geological Map of Italy (ISPRA, 2009; 2018) aiming to make the ‘language’ of geological maps of Mars and Earth as uniform as possible.