EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Radiogenic and stable Sr isotope geochemistry of regolith hosted REE deposits: a preliminary report

Hamed Pourkhorsandi1, Vinciane Debaille1, Sophie Decrée2, Jeroen de Jong1, Ali Yaraghi3, Georges Ndzana4, Martin Smith5, Kathryn Goodenough6, and Jindřich Kynický7
Hamed Pourkhorsandi et al.
  • 1Université Libre de Bruxelles, Belgium
  • 2Royal Belgian Institute of Natural Sciences, Belgium
  • 3Universiti Sains Malaysia, Malaysia
  • 4Université de Dschang, Cameroon
  • 5University of Brighton, UK
  • 6British Geological Survey, UK
  • 7BIC Brno spol. s r.o., Czechia

The increasing global demand for the rare earth elements (REE), that are critical for green energy production, justifies the necessity of understanding REE ore formation processes [1]. The main type of REE mineralization is mostly found in association with carbonatites and alkaline rocks [1,2]. In addition, in some cases the REE can also reach economical levels in secondary products called supergene REE resources [3]. Primary ore mineralizations mostly are composed of mineral phases that are highly unstable and easily soluble in the near-surface conditions in time. The secondary concentration of the REE in weathering regolith into economic deposits is more favourable than those in primary igneous rocks. As the main source of global heavy-REE, weathering deposits in southern China are the most studied ores of this type [4]. Recently, because of the recent surge in REE deposit exploration and their geological importance, other potentially similar deposits are being studied worldwide. Most of these works focus on mineralogical and elemental aspects of these systems. However, those weathering (in cooperation with alteration) systems are complex and a lot of questions on their formation remain unanswered.

In this work, we focus on the isotopic characterization of regolith hosted REE deposits. To better understand their formation, we utilize stable 88Sr/86Sr and radiogenic 87Sr/86Sr ratios, which have been used widely in understanding chemical weathering [5]. Mainly controlled by the incongruent weathering of primary minerals, Sr isotopes can help to identify the sources involved and the main factors affecting regolith hosted REE deposit formation. Strontium is especially important because, as Ca and K, it occurs in different REE-bearing primary and secondary minerals such as carbonates, ancylite, apatite, clays etc.

We will present different regolith profiles’ Sr isotopic data from Asia and Africa. Combining with the elemental and mineralogical data, we will devise a formation model for regolith hosted REE deposits.

References: [1] Goodenough et al. (2016) Ore Geo. Rev., 72, 838. [2] Chakhmouradian & Zaitsev (2012) Elements 8, 347. [3] Estrade et al. (2019) Ore Geo. Rev., 112, 103027. [4] Li et al. (2019) Econ. Geol., 114, 541. [5] Pett-Ridge et al. (2009) GCA, 73, 25.


How to cite: Pourkhorsandi, H., Debaille, V., Decrée, S., de Jong, J., Yaraghi, A., Ndzana, G., Smith, M., Goodenough, K., and Kynický, J.: Radiogenic and stable Sr isotope geochemistry of regolith hosted REE deposits: a preliminary report, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3180,, 2023.