Stability of the assemblage cordierite +K feldspar+quartz

✍ Scribed by F. Seifert

• Book ID: 104759895
• Publisher: Springer
• Year: 1976
• Tongue: English
• Weight: 374 KB
• Volume: 57
• Category: Article
• ISSN: 0010-7999
• DOI: 10.1007/bf00405224

✦ Synopsis

Under hydrous conditions the stability field of the assemblage Mg-cordierite + K feldspar + quartz is limited on its low-temperature side by the breakdown of cordierite + K feldspar into muscovite, phlogopite and quartz, whereas the high-temperature limit is given by eutectic melting. The compatibility field of the assemblage ranges from 530 ~ C to 745 ~ C at 1 kbar PH2o, from 635 to 725~ at 3 kbars PH2o, from 695 to 725~ at 5 kbars Pn2o and terminates at 5.5 kbars Pn2o. Most components not considered in the model system will tend to restrict this field even more. However, the condition PH~o < Ptot~ will increase the range of stable coexistence drastically, making the assemblage common at elevated temperatures from contact metamorphic rocks up to intermediate pressure granulites of appropriate bulk composition.