Immiscible fluids and melts trapped in garnet from pyroxenite-veined garnet peridotites related to metasomatism by basaltic melts
| Authors | |
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| Year of publication | 2024 |
| Type | Article in Proceedings |
| Conference | 4th European Mineralogical Conference |
| MU Faculty or unit | |
| Citation | |
| Web | https://emc-2024.org/ |
| Keywords | multiphase solid inclusions; garnet peridotite; immiscible fluids/melts; metasomatism |
| Attached files | |
| Description | Multiphase solid inclusions (MSI) in garnet peridotites in the Gföhl Unit of the Moldanubian Zone, Bohemian Massif, provide direct constraints on metasomatic processes in the mantle beneath the Central European Variscides. Here, we present results of a detailed study on two contrasting types of MSI coexisting in garnet in two pyroxenite-veined garnet peridotite bodies Pd1 and Pd2 hosted by Gföhl gneisses and located about 40 km apart. Despite the partial modifications of fluids during post-trapping processes, the study of MSI provided a valuable insight into complex metasomatic processes in mantle and chemical and physical character of metasomatizing medium. In both peridotite bodies, lherzolite metasomatism relates to percolation of primitive basaltic melts, now preserved as abundant garnet pyroxenite veins. The percolating basaltic melts were hydrous, CO2-bearing, with important admixture of crustal component (high Cs, Rb, Ba, Pb, U, Li, + REE contents in Pd2). Immiscible, dense Ti-Mg-Fe-rich oxide melt and solute-rich aqueous fluid (Pd1) and dense Ti-Mg-Fe-rich oxide melt along with high-density silicatecarbonate fluid (Pd2) likely separated from the basaltic melt upon cooling and were trapped in garnet. |
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