The evolution of Martian fissure eruptions and their plumbing systems

Abstract

On Earth, the investigation of fissure eruptions and their deposits provide fundamental insights into the evolution of the subsurface volcanic plumbing system. On Mars, we have limited evidence of the spatiotemporal evolution of fissure-fed volcanic systems, and thus the processes operating within their subsurface-feeding dykes remain poorly understood. The timescales of eruptive activity and the longevity of the associated plumbing systems remain unknown for Martian fissure-fed volcanism. Here, we performed high-resolution mapping and age dating of a ∼ 90-km long volcanic fissure system to uniquely unravel the evolution of the volcanic eruptions and the associated plumbing system both spatially and temporally. We show that through time, eruptive activity evolved from highly mobile lava flows that erupted along the entire fissure length to viscous lava flows that erupted at a single location and built up a cone. These observations suggest that the subsurface plumbing system became more chemically differentiated and the magma flow localized from a dyke-like, linear source to a point source with time. Our detailed reconstructions also suggest a long-lived (at least ≳ 9 Ma), and active volcanic plumbing system. Therefore, we argue that spatiotemporal mapping constitutes a powerful approach to understand the dynamic nature of subvolcanic plumbing systems on planetary bodies.