Author(s)

Frank Elliot Sahoa, Naivo Rabesiranana, Raoelina Andriambololona, Nicolas Finck, Christian Marquardt, Hörst Geckeis

Institut National des Sciences et Techniques Nucléaires (Madagascar-INSTN), Antananarivo, Madagascar.
Institute of Nuclear Waste and Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.

Studies are undertaken to characterize the uranium and thorium minerals of south-east Madagascar. Seven selected uranothorianite bearing pyroxenites samples from old abandoned uranium quarries in Tranomaro, south Amboasary, Madagascar (46°28'00"E, 24°36'00"S) have been collected. To determine the mineral micro-structure, they were investigated for qualitative identification of crystalline compounds by using X-ray powder diffraction analytical method (XRD). Results showed that the uranium and thorium compounds, as minor elements, were present in various crystalline structures. Thorium, as thorianite, is present in a simple ThO₂ cubic crystalline system, whereas the uranium component of the Tranomaro uranothorianite samples is oxide-based and is a mixture of complex oxidation states and crys-talline systems. Generally called uraninite, its oxide compounds are present in more than eight phases.

Tranomaro; Madagascar; Uranothorianite; Crystallography; XRD

F. Sahoa, N. Rabesiranana, R. Andriambololona, N. Finck, C. Marquardt and H. Geckeis, "Crystallographic Study of Uranium-Thorium Bearing Minerals in Tranomaro, South-East Madagascar," Journal of Minerals and Materials Characterization and Engineering, Vol. 1 No. 6, 2013, pp. 347-352. doi: 10.4236/jmmce.2013.16053.