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Eruptive, Hydrological and Glacial Dynamics, and Tephra Chronology of Subglacial Eruptions |
1 Department of Geological Sciences, Brown University, Providence, RI 02912, USA james_head{at}brown.edu
2 Environmental Sciences Department, Lancaster University, Lancaster LA14YQ, UK L.Wilson{at}lancaster.ac.uk
The advent of a global cryosphere likely occurred very early in the history of Mars, and much of the available water and related volatiles (CO2, clathrates, etc.) were sequestered within and below the cryosphere. This means that magmatism (plutonism and volcanism) as a geological process throughout the history of Mars cannot be fully understood without accounting for the interaction of magma and water (and related species) in both solid and liquid form. We review and outline the probable configuration of water and ice deposits in the history of Mars, describe environments and modes of magma-H2O interaction, and provide specific examples from the geological record of Mars. Magma and water-ice interactions have been interpreted to have formed: (1) massive pyroclastic deposits; (2) large-scale ground collapse and chaotic terrain; (3) major outflow channels; (4) mega-lahars dwarfing terrestrial examples; (5) sub-ice-sheet eruptions and edifices; (6) pseudocraters; (7) landslides on volcanic edifice flanks; and (8) hydrothermal sites. The global nature of the cryosphere, its longevity, and the diversity of environments means that Mars is an excellent laboratory for the study of magma-H2O interactdions and the role of related volatile species.
