EAST TENNANT DRILLING PROGRAM, NT
A suite of thin sections from the East Tennant Deep Drilling Project was submitted for general petrographic description and interpretation.
The project was located in the south-eastern Northern Territory, between Tennant Creek and the Queensland border. The thin sections were sampled from boreholes drilled through a range of cover sequences into basement rocks.
The project aimed to support U–Pb zircon geochronology study and, therefore, to characterise the occurrence of zircons in situ and provide a general petrographic description that included rock texture, mineralogy, alteration and structure. Igneous-, detrital- and metamorphic-origin zircon and monazite were recognised.
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- Photomicrograph shows hornblende-biotite granite, showing an igneous monazite grain in K-feldspar (crossed-polarised light).
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- A photomicrograph of biotite-hornblende granite showing elongated, euhedral zircons enclosed in biotite. Zircons are surrounded by pleochroic halos due to metamictic decay and have inner zoning (plane-polarised light).