Peralkaline trachytic magma erupted on Terceira, in the Azores are derived from associated basalts by extreme fractional crystallization of an assemblage including amphibole. The eruption of 1761 produced both trachytic and hybrid basaltic lavas and exemplifies magma mixing processes that occurred frequently in the past. Mingling of basaltic magmas produces homogeneous hybrid magmas; mingling between basaltic and trachytic liquids is inhibited by thermal quench of the basaltic magma. Hybridization of benmoreitic magma into basalt may account for its rarity in oceanic island lava suites. / Convection observed in an experimental basalt-pantellerite melt system is not attributable to gravitational instability at the nominally horizontal multicomponent free-diffusion boundary. Stresses due to diffusion in the viscoelastic silicate melts produced a meniscus; inclined density gradients at the meniscus cause convection. / Glassy pumice samples have been leached at ambient conditions, and have lost over 25% of F, Na, K, Si, Fe, Ti and Mn originally present; U, Al, Nb, Ca, Y, Rb and REE show smaller but significant losses.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.41732 |
| Date | January 1993 |
| Creators | Mungall, James E. |
| Contributors | Martin, R. F. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Earth and Planetary Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001393447, proquestno: NN94693, Theses scanned by UMI/ProQuest. |
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