Trace element abundances in megacrysts and their host basalts; constraints on partition coefficients and megacryst genesis.
Irving, Anthony J; Frey, Frederick A (1984) Trace element abundances in megacrysts and their host basalts; constraints on partition coefficients and megacryst genesis. Geochimica et Cosmochimica Acta. 48; 6, Pages 1201-1221. 1984. .
| Authors | Irving, Anthony J; Frey, Frederick A |
|---|---|
| Year | 1984 |
| Title | Trace element abundances in megacrysts and their host basalts; constraints on partition coefficients and megacryst genesis. |
| Source | Geochimica et Cosmochimica Acta. 48; 6, Pages 1201-1221. 1984. . |
| Publisher | Pergamon. Oxford, International. 1984. |
| Document type | Serial |
| ISSN | 0016-7037 |
| GeoRef | 1985-013960 |
| Keywords | alkaline-earth-metals; basalts-; chemical-composition; genesis-; geochemistry-; igneous-rocks; isotopes-; major-elements; major-element-analyses; megacrysts-; metals-; mineral-composition; partitioning-; phase-equilibria; Sr-87-Sr-86; stable-isotopes; strontium-; trace-elements; trace-element-analyses; volcanic-rocks |
| DOI | 10.1016/0016-7037(84)90056-5 |
Abstract
Consideration of phase equilibria, major element partitioning and isotopic ratios indicate that most of the pyroxene and amphibole megacrysts may have been in equilibrium with their host magmas at high pressures mostly 10-25 kb. In contrast, it is unlikely that mica, anorthoclase, apatite and zircon megacrysts formed in equilibrium with their host basalts; instead, we conclude that they were precipitated from more evolved magmas and have been mixed into their present host magmas. Consequently, the trace element abundance ratios for megacrysts/host should not be interpreted as partition coefficients, but only as guides for understanding trace element partitioning during high pressure petrogenesis.