Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Provenance Interpretation of the Permian sands of Southern Australia Using Opaque Minerals

Authors
Asadollah Granmayeh 1
Reza Moussavi-Harami 2
Victor Gostin 2
1 Department of Geology, Faculty of Earth Science, Shahid Beheshti University, Tehran, Iran
2 Department of Geology, University of Adelaide, South Australia
Abstract
The Permian sediments of southern Australia consist mainly of sand, mud, till and erratics that have been deposited in glacial environments. They are composed of light and heavy minerals and rock fragments. For analysis of opaque minerals, first they were separated by magnet and the Frantz Electronic Separator from other minerals, then they were analyzed by the electron microprobe.
Ilmenite can be found in different types of igneous and metamorphic rocks. The detrital ilmenite grains usually contain unique chemical composition, therefore, they can be used as an indicator in provenance interpretation. Ilmenite also show compositional variation that is mainly related to the source rock paragenesis. The amount of TiO2 in the ilmenite grains from metamorphic rocks is more than those from igneous rocks. The concentration of MgO is less than 0.4 Wt% and MnO is less than 5 wt% in the ilmenite of the metamorphic rocks of the East Antarctica, Kanmantoo Group and Permian erratics. Ilmenite grains with MgO of more than 0.4 Wt% and MnO of more than 5 wt% are found in the igneous rocks, such as Encounter Bay Granites, Granite of East Antarctica and Permian etrratics. So, ilmenite grains from metamorphic and igneous source rocks are chemically distinct and can be used for interpretation of provenance
More than 95 percent of the detrital ilmenite grains in the Permian sands have similar composition to the ilmenite from metamorphic rocks. Therefore, they have mainly been derived from the high-grade metamorphic rocks that have been examined. Based on this study, it can be concluded that the opaque minerals (particularly ilmenite), because of their distinct chemical composition, can be used for source rock predication and interpretation.
Keywords
Opaque minerals
Southern Australia
Subjects
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Scientific Quarterly Journal of Geosciences
Volume 4, 15-16
Spring & Summer 1995, Vol. 4,No. 15-16
Summer 1995
Pages 14-27