The use of oxygen isotope geothermometry on the granulites and related intrusives, Musgrave Ranges, central Australia

✍ Scribed by Allan F. Wilson; David C. Green; Lawrence E. Davidson

• Book ID: 104745706
• Publisher: Springer
• Year: 1970
• Tongue: English
• Weight: 929 KB
• Volume: 27
• Category: Article
• ISSN: 0010-7999
• DOI: 10.1007/bf00371982

✦ Synopsis

Oxygen isotope equilibration involving quartz, feldspar and magnetite has taken place within the granulites of the metamorphic aureole of the intrusive charnockitic Ernabelta Adamellite, and a temperature of approximately 550 ~ C is indicated by ~so/~60 values from quartz-magnetite and plagioclase-magnetite pairs. Pyroxene-magnetite fractionations are larger than equilihi'ium fraetionations at this temperature, and demonstrate that caution is necessary in assigning estimates of temperature to highly metamorphosed rocks.

The intrusive adamellite and related fine-grained and pegma~itie phases appear to have attained oxygen isotope equilibrium with the granulites at a similar temperature (approx. 550 ~ C) which is here regarded as a late metaraorphic equilibration temperature rather than the maximum temperature (estimated to be about, 780 ~ C) reached within the aureole.

Oxygen was extracted from the minerals by means of bromine pentafluoride, and the isotopes were successfully measu~'~cl without the normal prior conversion of oxygen to carbon dioxide.