HRTEM study of zircon from Eliseev anorthosite complex, Antarctica

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:468897

Wirth, R; Kaempf, H ^[1]; Hoehndorf, A ^[2]

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1. GeoForschungsZentrum Potsdam (Germany)
2. Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany)

Zircon-bearing rocks of this study are metamorphic oxide-apatite gabbronorites (OAGN) from the Eliseev Anorthosite Complex, Wohlthat-Massif, East Antarctica. These unusual rocks are strongly enriched in accessory minerals apatite: <10 vol.%; zircon: < 1 vol.. Three steps in the evolution of these rocks are distinguished: a magnetic formation, followed by a granulite facies metamorphism and finally a tectonomagmatic overprint. The zircon crystals of this study are brown colored, up to 12 mm in length and up to 3 mm wide. Petrological investigations show that zircon has formed during the granulite facies event. Optical microscopy and cathodoluminiscence microscopy reveal a rhythmic zoning and many microcracks. The concentrations of uranium and thorium are low (U: 34-89 ppm and Th: 3-9 ppm). The radiation damage by radioactive decay of U and Th is expected to be minor due to the low uranium and thorium content. The investigations were carried out in a Philips CM200 transmission electron microscope. Analytical electron microscopy was performed by energy dispersive analysis (EDAX).

• OSTI ID: 468897
• Report Number(s): CONF-960877--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACKS
CRYSTAL STRUCTURE
PETROLOGY
TRANSMISSION ELECTRON MICROSCOPY
ZIRCON