Understanding Martian megaflood-infiltration Landscapes at Hebrus Valles through Laboratory Experiments

Most of the Martian outflow channels have terminal areas buried beneath the younger sediments of the northern plains. Hebrus Valles, situated SE of Utopia Planitia, is exceptional in that its lowermost areas shows an abrupt disappearance of channels into a large cluster of pits. Our study aims to document the possibility of Hebrus Valles interacting with some preexisting underground cavernous networks. We conducted a series of flume experiments to simulate infiltration, including polygonally tunneling buried in sand. To replicate the Hebrus morphology, we constructed an orthogonal pattern of ice slabs before the experimentation, which after melting, simulated cave geometries. Our results reproduce incision features like those at the terminus of Hebrus Valles, implying that these discontinuities facilitated underground conduit generation. Our results provide the first laboratory-based confirmation of this type of catastrophic flood with infiltration processes inferred from remote-sensing observations. Our laboratory results show that floods are captured by sinkholes and can deliver a regional interconnection of channels and caves, which should have contributed actively to the dynamic of such floodwater infiltration in Hebrus Valles. Reference: Costard, F., Rodriguez, JAP, E. Godin, A. Séjourné, & J. Kargel. (2024). Deciphering Martian Flood Infiltration Processes at Hebrus Valles: Insights from Laboratory Experiments and Remote Sensing Observations. J. Geophys. Res. Planets. 129, e2023JE007770, doi/10.1029/2023JE00777