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Partial Melting of Plagioclase-Free Garnet–Two-Mica Metapelite As a Model of the Formation of Ultra-Potassic Felsic Magmas under Conditions of the Continental Crust.
- Source :
-
Doklady Earth Sciences . Dec2022, Vol. 507 Issue 2, p1064-1070. 7p. - Publication Year :
- 2022
-
Abstract
- To study the formation of S-type ultra-potassic granitic melts under the conditions of the continental crust, we conducted experiments on partial melting of plagioclase-free garnet–two-mica metapelite (with accessory apatite and ilmenite) at 6, 10, and 15 kbar and 700–900°C. Rock melting is driven by a series of peritectic melting reactios as a function of pressure and starts at temperatures of 750–800, ~800, and ~850°C at 6, 10, and 15 kbar, respectively, reflecting the positive dP/dT slope of the solidus. These P–T-conditions of melting, compositions of mineral assemblages and granitic melts formed during melting of plagioclase-free metapelites are similar to those formed during melting of plagioclase-bearing two-mica assemblages. The high K2O content (7–8 wt %) at a K2O/Na2O ratio of >8–10 is the main feature of the composition of the melt, which forms upon melting of plagioclase-free metapelite. These features are similar to the compositions of S-type ultra-potassic rhyolites, which form in extension tectonic settings. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PLAGIOCLASE
*MELTING
*CONTINENTAL crust
*MAGMAS
*ILMENITE
Subjects
Details
- Language :
- English
- ISSN :
- 1028334X
- Volume :
- 507
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Doklady Earth Sciences
- Publication Type :
- Academic Journal
- Accession number :
- 161326435
- Full Text :
- https://doi.org/10.1134/S1028334X22600724