Details
| Original language | English |
|---|---|
| Pages (from-to) | 1-21 |
| Number of pages | 21 |
| Journal | Mineralogy and Petrology |
| Volume | 97 |
| Issue number | 1-2 |
| Publication status | Published - 5 Aug 2009 |
Abstract
Crystallization experiments were performed on quartz diorite (~55 wt.% SiO2, 3.1-8.4 wt.% MgO) from the Gȩsiniec Intrusion (Bohemian Massif, SW Poland) at 1-2 kbar, 750-850°C, various mole fractions of water and with fO2 buffered by the NNO buffer. The two natural quartz diorites (leucocratic poikilitic quartz diorite - 'LPD' and melanocratic quartz diorite - 'MD') differ in whole rock and mineral composition with MD being richer in MgO and poorer in CaO than LPD, probably due to accumulation of mafic minerals or melt removal in MD. LPD represents melt composition and is used to reconstruct crystallization conditions in the Gȩsiniec Intrusion. The crystallization history of LPD magma, deduced from experimental and natural mineral compositions, includes a higher pressure stage probably followed by emplacement at ~2 kbar of partly crystallized magma at temperatures ~850-800°C and quick cooling. The mineral assemblage present in LPD requires water contents in the magma of at least 5 wt% and oxygen fugacity below that controlled by the NNO buffer. The compositions of mafic minerals in the MD composition were equilibrated at temperatures below 775°C and at subsolidus conditions. The equilibration was probably due to the reaction between water-rich, oxidizing residual melt and the cumulatic-restitic mineral assemblage. MD is characterized by occurrence of the euhedral cummingtonite and increasing anorthite content in the rims of plagioclase. A similar reaction was reproduced experimentally in both LPD and MD compositions indicating that cummingtonite may be a late magmatic phase in quartz dioritic systems, crystallizing very close to solidus and only from water saturated magma.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geophysics
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Mineralogy and Petrology, Vol. 97, No. 1-2, 05.08.2009, p. 1-21.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Crystallization of quartz dioritic magmas at 2 and 1 kbar
T2 - Experimental results
AU - Pietranik, Anna
AU - Holtz, Francois
AU - Koepke, Jürgen
AU - Puziewicz, Jacek
N1 - Funding information: This work was supported by a DAAD fellowship to AP and by the DAAD exchange program between the Leibniz University of Hannover and the University of Wroc?aw, Poland. AP thanks Roman Botcharnikov, Sandrin Feig and Kevin Klimm for invaluable advice on how to prepare experiments. AP also thanks Otto Diedrich and other people from the workshop. Kirsten Drüppel and Bruno Scaillet are thanked for helpful comments on the manuscript.
PY - 2009/8/5
Y1 - 2009/8/5
N2 - Crystallization experiments were performed on quartz diorite (~55 wt.% SiO2, 3.1-8.4 wt.% MgO) from the Gȩsiniec Intrusion (Bohemian Massif, SW Poland) at 1-2 kbar, 750-850°C, various mole fractions of water and with fO2 buffered by the NNO buffer. The two natural quartz diorites (leucocratic poikilitic quartz diorite - 'LPD' and melanocratic quartz diorite - 'MD') differ in whole rock and mineral composition with MD being richer in MgO and poorer in CaO than LPD, probably due to accumulation of mafic minerals or melt removal in MD. LPD represents melt composition and is used to reconstruct crystallization conditions in the Gȩsiniec Intrusion. The crystallization history of LPD magma, deduced from experimental and natural mineral compositions, includes a higher pressure stage probably followed by emplacement at ~2 kbar of partly crystallized magma at temperatures ~850-800°C and quick cooling. The mineral assemblage present in LPD requires water contents in the magma of at least 5 wt% and oxygen fugacity below that controlled by the NNO buffer. The compositions of mafic minerals in the MD composition were equilibrated at temperatures below 775°C and at subsolidus conditions. The equilibration was probably due to the reaction between water-rich, oxidizing residual melt and the cumulatic-restitic mineral assemblage. MD is characterized by occurrence of the euhedral cummingtonite and increasing anorthite content in the rims of plagioclase. A similar reaction was reproduced experimentally in both LPD and MD compositions indicating that cummingtonite may be a late magmatic phase in quartz dioritic systems, crystallizing very close to solidus and only from water saturated magma.
AB - Crystallization experiments were performed on quartz diorite (~55 wt.% SiO2, 3.1-8.4 wt.% MgO) from the Gȩsiniec Intrusion (Bohemian Massif, SW Poland) at 1-2 kbar, 750-850°C, various mole fractions of water and with fO2 buffered by the NNO buffer. The two natural quartz diorites (leucocratic poikilitic quartz diorite - 'LPD' and melanocratic quartz diorite - 'MD') differ in whole rock and mineral composition with MD being richer in MgO and poorer in CaO than LPD, probably due to accumulation of mafic minerals or melt removal in MD. LPD represents melt composition and is used to reconstruct crystallization conditions in the Gȩsiniec Intrusion. The crystallization history of LPD magma, deduced from experimental and natural mineral compositions, includes a higher pressure stage probably followed by emplacement at ~2 kbar of partly crystallized magma at temperatures ~850-800°C and quick cooling. The mineral assemblage present in LPD requires water contents in the magma of at least 5 wt% and oxygen fugacity below that controlled by the NNO buffer. The compositions of mafic minerals in the MD composition were equilibrated at temperatures below 775°C and at subsolidus conditions. The equilibration was probably due to the reaction between water-rich, oxidizing residual melt and the cumulatic-restitic mineral assemblage. MD is characterized by occurrence of the euhedral cummingtonite and increasing anorthite content in the rims of plagioclase. A similar reaction was reproduced experimentally in both LPD and MD compositions indicating that cummingtonite may be a late magmatic phase in quartz dioritic systems, crystallizing very close to solidus and only from water saturated magma.
UR - http://www.scopus.com/inward/record.url?scp=67949104728&partnerID=8YFLogxK
U2 - 10.1007/s00710-009-0070-5
DO - 10.1007/s00710-009-0070-5
M3 - Article
AN - SCOPUS:67949104728
VL - 97
SP - 1
EP - 21
JO - Mineralogy and Petrology
JF - Mineralogy and Petrology
SN - 0930-0708
IS - 1-2
ER -