Sub-Volcanic Structure Beneath Marius Hills, Moon, Inferred From Vent Distribution

The lunar region of Marius Hills has been interpreted as either a shield volcano or a volcanic complex lacking a central zone of magma accumulation at depth. The magmatic structure beneath Marius Hills inferred from gravity anomalies suggests the presence of dyke groups within the upper 20 km of lunar crust. However, the difference in character between the north and south free-air anomalies remains enigmatic. In this work, we study the surface distribution of volcanic vents as an alternative method to obtain information concerning the magmatic structure beneath Marius Hills. A robust identification of independent groups of vents is made using several clustering methods, therefore avoiding possible biases associated with the particular form of analysis. The obtained results confirm the presence of the zones of magma accumulation inferred from gravity analysis but also serve to delineate in more detail the structure of the underlying plumbing system. Furthermore, the joint interpretation of the gravity, topography, and vent distribution analysis indicates that although Marius Hills should not be considered as a fully developed shield volcano as Mauna Kea on Earth, it shares some aspects of other terrestrial large shields where crustal differences (in thickness, lithology, presence of faults, etc.) exert a strong influence on the distribution of vents at the surface.

Automated summary

The surface distribution of volcanic vents in the lunar region of Marius Hills provides important information about the magmatic structure beneath. The results confirm the presence of magma accumulation zones and reveal the detailed structure of the plumbing system. The joint interpretation of gravity, topography, and vent distribution analysis suggests similarities to other terrestrial large shields.