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Venus: Vertical accretion of crust and depleted mantle and implications for geological history and processesModels for the vertical accretion of a basaltic crust and depleted mantle layer on Venus over geologic time predict the eventual development of a net negatively buoyant depleted mantle layer, its foundering and its remixing with the underlying mantle. The consequences of the development of this layer, its loss, and the aftermath are investigated and compared to the geologic record of Venus revealed by Magellan. The young average age of the surface of Venus (several hundred million years), the formation of the heavily deformed tessera regions, the subsequent emplacement of widespread volcanic plains, the presently low rate of volcanic activity, and impact crater population that cannot be distinguished from a completely spatially random distribution, and the small number of impact craters embayed by volcanism, are all consistent with the development of a depleted mantle layer, its relatively rapid loss followed by large-scale volcanic flooding, and its subsequent reestablishment. We outline a 'catastrophic' tectonic resurfacing model in which the foundering of the depleted mantle layer several hundred million years ago caused globally extensive tectonic deformation and obliteration of the cratering record, accompanied by upwelling of warm fertile mantle and its pressure-release melting to produce extensive surface volcanism in the following period. Venus presently appears to be characterized by a relatively thick depleted mantle layer and lithosphere reestablished over the last several hundred million years following the previous instability event inferred to have produced the tessera terrain.
Document ID
19950036410
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Head, James W.
(Brown Univ. Providence, RI, United States)
Parmentier, E. M.
(Brown Univ. Providence, RI, United States)
Hess, P. C.
(Brown Univ. Providence, RI, United States)
Date Acquired
August 16, 2013
Publication Date
October 1, 1994
Publication Information
Publication: Planetary and Space Science
Volume: 42
Issue: 10
ISSN: 0032-0633
Subject Category
Lunar And Planetary Exploration
Accession Number
95A68009
Funding Number(s)
CONTRACT_GRANT: NAGW-713
CONTRACT_GRANT: NAGW-3488
CONTRACT_GRANT: NAGW-1928
Distribution Limits
Public
Copyright
Other

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