Analogue modelling of volcano flank terrace formation on Mars
Paul K. Byrne, Eoghan P. Holohan, Matthieu Kervyn, Benjamin Van Wyk De Vries, Valentin R. Troll, 2015. "Analogue modelling of volcano flank terrace formation on Mars", Volcanism and Tectonism Across the Inner Solar System, T. Platz, M. Massironi, P. K. Byrne, H. Hiesinger
Download citation file:
Of the features that characterize large shield volcanoes on Mars, flank terraces remain the most enigmatic. Several competing mechanisms have been proposed for these laterally expansive, topographically subtle landforms. Here we test the hypothesis that horizontal contraction of a volcano in response to the down-flexing of its underlying basement leads to flank terracing. We performed a series of analogue models consisting of a conical sand–plaster load emplaced on a basement comprising a layer of brittle sand–plaster atop a reservoir of viscoelastic silicone. Our experiments consistently produced a suite of structures that included a zone of concentric extension distal to the conical load, a flexural trough adjacent to the load base and convexities (terraces) on the cone’s flanks. The effects of variations in the thickness of the brittle basal layer, as well as in the volume, slope and planform eccentricity of the cone, were also investigated. For a given cone geometry, we find that terrace formation is enhanced as the brittle basement thickness decreases, but that a sufficiently thick brittle layer can enhance the basement’s resistance to loading such that terracing of the cone is reduced or even inhibited altogether. For a given brittle basement thickness, terracing is reduced with decreasing cone slope and/or volume. Our experimental results compare well morphologically to observations of terraced edifices on Mars, and so provide a framework with which to understand the developmental history of large shield volcanoes on the Red Planet.
Figures & Tables
Volcanism and tectonism are the dominant endogenic means by which planetary surfaces change. This book aims to encompass the broad range in character of volcanism, tectonism, faulting and associated interactions observed on planetary bodies across the inner solar system - a region that includes Mercury, Venus, Earth, the Moon, Mars and asteroids. The diversity and breadth of landforms produced by volcanic and tectonic processes is enormous, and varies across the inner solar system bodies. As a result, the selection of prevailing landforms and their underlying formational processes that are described and highlighted in this volume are but a primer to the expansive field of planetary volcanism and tectonism. This Special Publication features 22 research articles about volcanic and tectonic processes manifest across the inner solar system.