Recent Volcanic and Fluvial Activity in the Region of Harmakhis Vallis, Mars

Glamoclija, Mihaela¹, Gian Gabriele Ori², Lucia Marinangeli², Goro Komatsu³, Jouko Raitala⁴ (1) Department of Geological Science, Indiana University; and International School of Planetary Sciences, Università d’Annunzio, Bloomington, IN (2) IRSPS, Pescara, Italy (3) Università d’Annunzio, Pescara, Italy (4) University of Oulu, Oulu, Finland

Geologic mapping and geomorphic analyses of Harmakhis Vallis in the eastern Hellas region (lat. -35˚ to –42˚S; lon. 91˚ to 98˚E) were conduced to distinguish and characterize geologic units and processes that operated in the source region of Harmakhis Vallis and its vicinity. Long and complex history of degradation and modification involves mass wasting processes, volcanism and fluvial activity; confronting effects of climate-induced slow mass-wasting processes with temporary high geothermal variations caused by impact events and volcanism in the area. Our analyses of currently available imagery from the area (Viking imagery, MOLA altimetry, wide and narrow angle MOC images, THEMIS VIS and IR (nighttime and daytime) images, HRSC: H0038, H0528 images, and stereo-derived topography) revealed evidence for a recent geothermal excursion with small spatial exposure. This recent, temporary, and a space-limited relatively high geothermal anomaly was most likely caused by reactivation of volcanic sources during the most recent history of the region. Its importance is not solely as “a witness” of the recent hydrothermal activity resurged within last approximately 400,000 years on the plain; but also to give support to more detail researches of the Harmakhis Vallis region and other volcanic provinces on Mars that may be of a high astrobiological interest.

Further analyses of new MOC narrow angle images and incorporation of OMEGA data may provide information of the physical and chemical properties of the surface material to further refine knowledge of types, distribution, and origin of geologic units in the area.