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Magmatic and Tectonic Processes in Amazonis Planitia: Implications for Late Amazonian Volcanism

Christopher W. Hamilton 1, Wesley S. Tucker1, Joana R. C. Voigt2, and Jeffrey C. Andrews-Hanna1

  • Affiliations: 1Lunar and Planetary Laboratory, University of Arizona, Tucson, USA; 2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 254

  • Programme No: 1.4.13

  • Theme 1 > Session 4

Abstract

Pit chains in Amazonis Planitia occur within geologically recent (i.e., Late Amazonian) volcanic units. These pit chains appear to be the source of some local lava flow units, which is unexpected given that the location is nearly midway between the Tharsis and Elysium volcanic provinces and has previously been considered a sink for flows sourced from the surroundings rather than a volcanic source region itself. However, the pit chains and flow units are located near the intersection of two major strike-slip fault systems, suggesting a link between magmatic and tectonic processes in the region. This work presents: (1) regional geologic mapping of central Amazonis Planitia to establish a context for observed pit crater chains and flow units; (2) detailed facies mapping of the pit crater chains, including detailed topographic and volumetric analysis using stereo-derived digital terrain models; and (3) modeling of strike-slip faulting processes to assess if observed dilatational extension at the fault intersection could have generated extensional stresses conducive to magmatic ascent. Results show that the lava channels feeding flow units near the fault intersection dip back toward the axis of the pit crater chain, which can be explained by syn- and/or post-emplacement subsidence of an underlying magma chamber. These results further imply that tectonic processes strongly affect the locations of magma migration through the martian crust, thereby leading to volcanic activity that is more widely spread than previously believed.