Cordierite-spinel-quartz assemblages: A potential geobarometer
The composition of (Mg-Zn-Fe+2)-aluminate-spinel coexisting with cordierite and quartz is potentially a sensitive geobarometer in rock types such as cordierite ‒ anthophyllite rocks which are not well suited to most other geobarometers. Calculations based on thermodynamic data and the end member rea...
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Geological Society of Finland
1986-06-01
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doaj-72e54412f94143499973edc0d5dd02ca2020-11-25T00:54:43ZengGeological Society of FinlandBulletin of the Geological Society of Finland0367-52111799-46321986-06-015819510810.17741/bgsf/58.1.007Cordierite-spinel-quartz assemblages: A potential geobarometerF. SeifertJ.C. SchumacherThe composition of (Mg-Zn-Fe+2)-aluminate-spinel coexisting with cordierite and quartz is potentially a sensitive geobarometer in rock types such as cordierite ‒ anthophyllite rocks which are not well suited to most other geobarometers. Calculations based on thermodynamic data and the end member reactions demonstrated that the compositions of (Mg-Fe) ‒ cordierites and (Mg-Fe-Zn) ‒ aluminate spinels are only slightly affected by temperature but the effect of pressure is dramatic. With increasing pressure the XMg of the spinel changes from less than 0.1 at 1 bar to about 0.8 at 9 kbars. Comparison of pressures derived from this model for natural assemblages with known PT conditions shows good agreement but also points to the necessity of treating the effects of water on the stability of cordierite more quantitatively. http://www.geologinenseura.fi/bulletin/Volume58/sgs_bt_058_1_pages_095_108.pdfgeobarometercordieritespinelquartzphase relationsthermodynamic data |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
F. Seifert J.C. Schumacher |
spellingShingle |
F. Seifert J.C. Schumacher Cordierite-spinel-quartz assemblages: A potential geobarometer Bulletin of the Geological Society of Finland geobarometer cordierite spinel quartz phase relations thermodynamic data |
author_facet |
F. Seifert J.C. Schumacher |
author_sort |
F. Seifert |
title |
Cordierite-spinel-quartz assemblages: A potential geobarometer |
title_short |
Cordierite-spinel-quartz assemblages: A potential geobarometer |
title_full |
Cordierite-spinel-quartz assemblages: A potential geobarometer |
title_fullStr |
Cordierite-spinel-quartz assemblages: A potential geobarometer |
title_full_unstemmed |
Cordierite-spinel-quartz assemblages: A potential geobarometer |
title_sort |
cordierite-spinel-quartz assemblages: a potential geobarometer |
publisher |
Geological Society of Finland |
series |
Bulletin of the Geological Society of Finland |
issn |
0367-5211 1799-4632 |
publishDate |
1986-06-01 |
description |
The composition of (Mg-Zn-Fe+2)-aluminate-spinel coexisting with cordierite and quartz is potentially a sensitive geobarometer in rock types such as cordierite ‒ anthophyllite rocks which are not well suited to most other geobarometers. Calculations based on thermodynamic data and the end member reactions demonstrated that the compositions of (Mg-Fe) ‒ cordierites and (Mg-Fe-Zn) ‒ aluminate spinels are only slightly affected by temperature but the effect of pressure is dramatic. With increasing pressure the XMg of the spinel changes from less than 0.1 at 1 bar to about 0.8 at 9 kbars. Comparison of pressures derived from this model for natural assemblages with known PT conditions shows good agreement but also points to the necessity of treating the effects of water on the stability of cordierite more quantitatively.
|
topic |
geobarometer cordierite spinel quartz phase relations thermodynamic data |
url |
http://www.geologinenseura.fi/bulletin/Volume58/sgs_bt_058_1_pages_095_108.pdf |
work_keys_str_mv |
AT fseifert cordieritespinelquartzassemblagesapotentialgeobarometer AT jcschumacher cordieritespinelquartzassemblagesapotentialgeobarometer |
_version_ |
1725233137735172096 |