Mud volcanism and episodic outflow events explain pitted cones in Chryse and Acidalia Planitia, Mars

Pitted cones are widespread in the northern lowlands of Mars and are thought to result from mud volcanism. This study focuses on the pitted cones in Chryse and Acidalia Planitia. A deep learning model was used to classify pitted cones into three morphological classes. Class 1 cones are heavily degraded, with rough surfaces and irregular shapes; Class 2 cones are smoother, moderately eroded and more rounded; Class 3 cones are highly smooth, rounded, and have higher albedo than their surroundings. Thermal Emission Imaging System (THEMIS) data show that Classes 1 and 2 have thermal inertia similar to the surrounding terrain, suggesting they were affected by outflow‑related erosion and depositional mantling, while Class 3 cones have distinctly lower thermal inertia, indicating they were formed after the events. Age estimates indicate that major outflow events and following surface modification occurred between 3.66 Ga and 3.43 Ga. The findings indicate that mud volcanism might be the most plausible mechanism. These pitted cones in Chryse and Acidalia Planitia might be triggered by episodic outflow events, likely associated with a paleo-ocean around 3.66 Ga and subsequent major outflow events around 3.48 Ga. These results highlight the role of hydrological activity in shaping Martian geological history. Mud volcanism and hydrological activity could be responsible for the formation of pitted cones in Chryse and Acidalia Planitia on Mars, according to analysis of Thermal Emission Imaging System data and a deep learning-based morphological assessment.