Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication

Petrographic characterization of REE-Nb-Zr mineralization at the Dubbo trachyte, NSW Australia

Müller, C.; Mentoren: Schulz, B.; Atanasova, P.; Gutzmer, J.

Abstract

This thesis was the first study which intensively investigated the mineralisation and described the mineral transition between the supergene alterated and the main Toongi trachyte. Compared to other works on this trachyte the identified ore minerals differ. The works of Ramsden [1990, 1992] as well as the actually published mineral lists of Alkane resources Ltd. primarily deal with minerals of the supergene alterated zone. Within all three mineral lists there are major differences (cf. Table 5).
Due to the fact that this thesis, as well as the works of Ramsden, only used EDS measurements, a final evaluation is not possible.
The observed ore minerals often occur as small grains and as impregnation-like patches within the alterated matrix. Within the supergene alterated trachyte LREE are primary hosted by REEphosphates (monazite (Ce)) and zircon minerals, REE-fluorites (bastnaesite (Ce)) are not so important. HREE are primarily hosted by a Nb-Ta mineral. Major Nb hosting minerals are columbite and a Nb-Ta mineral. Zr is hosted by various Zr silicates, especially zircon. Within the main trachyte, LREE are hosted by REE-fluorites (bastnaesite (Ce)) and Zr-silicates (especially poikiloblastic zircon), REE-phosphates are not so important. HREE are primarily hosted by HREEY-(As) minerals. Major Zr hosting minerals are zircon and poikiloblastic zircon. Nb is primarily hosted by a Nb-Na mineral (natroniobite/lueshite) and less by a Nb-REE mineral. Most of the valuable minerals have a hydrothermal origin or they are products of alterated ores, respectively.
Only poikiloblastic zircon and Nb-Na-mineral have a magmatic origin.
Further investigations should confirm the mineral names by using more accurate measurements like X-Ray microanalysis. To determine the composition and temperature of the hydrothermal fluids the fluid inclusions should be investigated. Further investigations of samples out of the depths between 12 and 25 m (between sample DUB 5 and 6) could show the process of supergene mineral transformation more detailed.

Keywords: rare earth elements; metal deportment; trachyte

  • Master thesis
    TU Bergakademie Freiberg, 2015
    Mentor: Bernhard Schulz, Petya Atanasova, Jens Gutzmer
    116 Seiten

Permalink: https://www.hzdr.de/publications/Publ-22223