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The effects of Venus' thermal structure on buoyant magma ascentThe recent Magellan images have revealed a broad spatial distribution of surface volcanism on Venus. Previous work in modeling the ascent of magma on both Venus and Earth has indicated that the planetary thermal structure significantly influences the magmatic cooling rates and thus the amount of magma that can be transported to the surface before solidification. In order to understand which aspects of the thermal structure have the greatest influence on the cooling of ascending magma, we have constructed magma cooling curves for both plutonic and crack buoyant ascent mechanisms, and evaluated the curves for variations in the planetary mantle temperature, thermal gradient curvature with depth, surface temperature gradient, and surface temperature. The planetary thermal structure is modeled as T/T(sub 0) = 1-tau(1-Z/Z(sub 0)(exp n), where T is the temperature, T(sub 0) is the source depth temperature, tau = 1-(T(sub s)/T(sub 0)) where T(sub s) is the planetary surface temperature, Z is the depth, Z(sub 0) is the source depth, and n is a constant that controls thermal gradient curvature with depth. The equation is used both for mathematical convenience and flexibility, as well as its fit to the thermal gradients predicted by the cooling half-space models. We assume a constant velocity buoyant ascent, body-averaged magma temperatures and properties, an initially crystal-free magma, and the same liquidus and solidus for both Venus and Earth.
Document ID
19930005178
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Sakimoto, S. E. H.
(Johns Hopkins Univ. Baltimore, MD, United States)
Zuber, M. T.
(Johns Hopkins Univ. Baltimore, MD, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Lunar and Planetary Inst., Papers Presented to the International Colloquium on Venus
Subject Category
Lunar And Planetary Exploration
Accession Number
93N14366
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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