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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, E04S06, doi:10.1029/2006JE002793, 2007

Volcanism and volatile recycling on a one-plate planet: Applications to Venus

L. T. Elkins-Tanton

Department of Geological Sciences, Brown University, Providence, Rhode Island, USA


S. E. Smrekar

Jet Propulsion Laboratory, Pasadena, California, USA


P. C. Hess

Department of Geological Sciences, Brown University, Providence, Rhode Island, USA


E. M. Parmentier

Department of Geological Sciences, Brown University, Providence, Rhode Island, USA


Abstract

The surface of Venus displays volcanic features indicating eruption of lavas with a wide range of viscosities. We present numerical experiments showing that lithospheric gravitational instabilities can produce lavas with compositions consistent with the range of volcanic forms seen on Venus. The presence of incompatible elements and their oxides (specifically, water, carbon dioxide, and alkali elements) in trace- to percent-level concentrations in the Venusian mantle allows the formation of a variety of magmatic source regions. The pressure and temperature paths that the dense lithospheric materials travel as they sink into the Venusian mantle indicate that the lithospheric material may devolatilize as it sinks, enriching the surrounding upper mantle, or it may itself melt. These processes can produce magmas with a variety of compositions and viscosities, potentially consistent with the range of Venusian volcanic forms. These processes also suggest that Venus may recycle incompatible elements internally. Indeed, if Venus began with an internal volatile content, then no amount of partial melting can make it entirely volatile-free even in the absence of recycling into the interior. These models therefore suggest geodynamic processes that can produce a range of magmatic activity and retain some interior volatiles on a one-plate planet.

Received 14 July 2006; accepted 14 November 2006; published 30 March 2007.

Keywords: Venus; delamination; lithospheric foundering; numerical model.

Index Terms: 5410 Planetary Sciences: Solid Surface Planets: Composition (1060, 3672); 5430 Planetary Sciences: Solid Surface Planets: Interiors (8147); 5480 Planetary Sciences: Solid Surface Planets: Volcanism (6063, 8148, 8450); 6295 Planetary Sciences: Solar System Objects: Venus; 8148 Tectonophysics: Planetary volcanism (5480, 8450).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 1133378 bytes)

Citation: Elkins-Tanton, L. T., S. E. Smrekar, P. C. Hess, and E. M. Parmentier (2007), Volcanism and volatile recycling on a one-plate planet: Applications to Venus, J. Geophys. Res., 112, E04S06, doi:10.1029/2006JE002793.