Deep generation of magmatic gas on the moon and implications for pyroclastic eruptions.

Wilson, Lionel and Head, James W. (2003) Deep generation of magmatic gas on the moon and implications for pyroclastic eruptions. Geophysical Research Letters, 30 (12). p. 1605. ISSN 0094-8276

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Abstract

Lunar pyroclastic beads are interpreted to represent primitive magmas derived from great depths and rapidly erupted to the surface in explosive events. However, a detailed mechanism for gas generation at great depth and rapid magma transport to the surface has not yet been described. Furthermore, the pyroclastic beads are not petrogenetically related to basalts erupted near the sampling sites. We propose a model in which these conundrums are resolved through gas build-up in a low-pressure micro-environment near the tip of a magma-filled crack (dike) propagating rapidly from the magma source depth to the surface. The gas rich region consists of a free gas cavity overlying a foam extending vertically for ∼20 km. Eruption of the foam results in the widespread emplacement of unfractionated pyroclastic beads. Subsequent ascent of the underlying gas-free picritic magma is unlikely to occur, perhaps accounting for the lack of sampled eruptive equivalents.

Item Type:
Journal Article
Journal or Publication Title:
Geophysical Research Letters
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1908
Subjects:
?? geophysicsgeneral earth and planetary sciencesearth and planetary sciences(all)ge environmental sciences ??
ID Code:
21434
Deposited By:
Deposited On:
14 Jan 2009 13:16
Refereed?:
Yes
Published?:
Published
Last Modified:
16 Jul 2024 08:20