Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 538-553 |
| Seitenumfang | 16 |
| Fachzeitschrift | Lithos |
| Jahrgang | 102 |
| Ausgabenummer | 3-4 |
| Frühes Online-Datum | 30 Aug. 2007 |
| Publikationsstatus | Veröffentlicht - Mai 2008 |
Abstract
Crystallization experiments have been conducted in the system Na2O-K2O-MgO-FeO-Al2O3- SiO2-H2O (with 4% normative corundum) in order to constrain the stability of biotite as a function of water activity and the Mg# of biotite [Mg/(Mg +Fetotal)] in equilibrium with peraluminous granitic melts. The temperature at which biotite breakdown starts is strongly dependent on the Mg# of biotite. At 500 MPa, the temperature of biotite breakdown to form orthopyroxene increases from 750 °C to 830 °C, as the Mg# of biotite increases from 0.4 to 0.5. Considering that the system investigated is relevant for Ca-poor peraluminous biotite-bearing rocks (metapelites), the biotite dehydration curves obtained are used to discuss the melting reactions and the temperatures that lead to the formation of two distinct types of two-mica granites found in the South Bohemian batholith (specifically the Eisgarn and Deštná granites). The phase relationships were determined experimentally for the composition of these two granites in order to constrain the composition of the biotite in equilibrium with the melt in the protoliths. We demonstrate that Eisgarn granitic melts may have been generated at temperatures in the range 830-850 °C from melting reactions involving biotite with a Mg# up to 0.5 as a reactant. In contrast, Deštná granitic melts cannot have been generated from dehydration melting reactions involving biotite.
ASJC Scopus Sachgebiete
- Erdkunde und Planetologie (insg.)
- Geologie
- Erdkunde und Planetologie (insg.)
- Geochemie und Petrologie
Zitieren
- Standard
- Harvard
- Apa
- Vancouver
- BibTex
- RIS
in: Lithos, Jahrgang 102, Nr. 3-4, 05.2008, S. 538-553.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Biotite stability in peraluminous granitic melts
T2 - Compositional dependence and application to the generation of two-mica granites in the South Bohemian batholith (Bohemian Massif, Czech Republic)
AU - René, Miloš
AU - Holtz, Francois
AU - Luo, Cherhui
AU - Beermann, Oliver
AU - Stelling, Jan
N1 - Funding Information: This study was supported by the Ministry of Education, Youth and Sports of the Czech Republic (Project No. ME-555) and by the research plan (A V0Z 30460519) of Institute of Rock Structure and Mechanics of the CAS CR. Travel expenses and laboratory costs for the German participants were supported by the DAAD (PPP-program) and DFG (436 TSE 113/48/0-1). Copyright: Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2008/5
Y1 - 2008/5
N2 - Crystallization experiments have been conducted in the system Na2O-K2O-MgO-FeO-Al2O3- SiO2-H2O (with 4% normative corundum) in order to constrain the stability of biotite as a function of water activity and the Mg# of biotite [Mg/(Mg +Fetotal)] in equilibrium with peraluminous granitic melts. The temperature at which biotite breakdown starts is strongly dependent on the Mg# of biotite. At 500 MPa, the temperature of biotite breakdown to form orthopyroxene increases from 750 °C to 830 °C, as the Mg# of biotite increases from 0.4 to 0.5. Considering that the system investigated is relevant for Ca-poor peraluminous biotite-bearing rocks (metapelites), the biotite dehydration curves obtained are used to discuss the melting reactions and the temperatures that lead to the formation of two distinct types of two-mica granites found in the South Bohemian batholith (specifically the Eisgarn and Deštná granites). The phase relationships were determined experimentally for the composition of these two granites in order to constrain the composition of the biotite in equilibrium with the melt in the protoliths. We demonstrate that Eisgarn granitic melts may have been generated at temperatures in the range 830-850 °C from melting reactions involving biotite with a Mg# up to 0.5 as a reactant. In contrast, Deštná granitic melts cannot have been generated from dehydration melting reactions involving biotite.
AB - Crystallization experiments have been conducted in the system Na2O-K2O-MgO-FeO-Al2O3- SiO2-H2O (with 4% normative corundum) in order to constrain the stability of biotite as a function of water activity and the Mg# of biotite [Mg/(Mg +Fetotal)] in equilibrium with peraluminous granitic melts. The temperature at which biotite breakdown starts is strongly dependent on the Mg# of biotite. At 500 MPa, the temperature of biotite breakdown to form orthopyroxene increases from 750 °C to 830 °C, as the Mg# of biotite increases from 0.4 to 0.5. Considering that the system investigated is relevant for Ca-poor peraluminous biotite-bearing rocks (metapelites), the biotite dehydration curves obtained are used to discuss the melting reactions and the temperatures that lead to the formation of two distinct types of two-mica granites found in the South Bohemian batholith (specifically the Eisgarn and Deštná granites). The phase relationships were determined experimentally for the composition of these two granites in order to constrain the composition of the biotite in equilibrium with the melt in the protoliths. We demonstrate that Eisgarn granitic melts may have been generated at temperatures in the range 830-850 °C from melting reactions involving biotite with a Mg# up to 0.5 as a reactant. In contrast, Deštná granitic melts cannot have been generated from dehydration melting reactions involving biotite.
KW - Biotite stability
KW - Crystal fractionation
KW - Crystallisation
KW - Experiments
KW - S-type granite
UR - http://www.scopus.com/inward/record.url?scp=43049178084&partnerID=8YFLogxK
U2 - 10.1016/j.lithos.2007.07.022
DO - 10.1016/j.lithos.2007.07.022
M3 - Article
AN - SCOPUS:43049178084
VL - 102
SP - 538
EP - 553
JO - Lithos
JF - Lithos
SN - 0024-4937
IS - 3-4
ER -