Deep generation of magmatic gas on the Moon and implications for pyroclastic eruptions
Article first published online: 18 JUN 2003
Copyright 2003 by the American Geophysical Union.
Geophysical Research Letters
Volume 30, Issue 12, June 2003
How to Cite
2003), Deep generation of magmatic gas on the Moon and implications for pyroclastic eruptions, Geophys. Res. Lett., 30, 1605, doi:10.1029/2002GL016082, 12., and (
- Issue published online: 18 JUN 2003
- Article first published online: 18 JUN 2003
- Manuscript Accepted: 4 MAR 2003
- Manuscript Revised: 17 FEB 2003
- Manuscript Received: 9 AUG 2002
 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.