Post-magmatic processes in carbonatitic systems

Carbonatite lava

Carbonatite lava at Ol Doinyo Lengai volcano, Tanzania © Tomkraft, licensed under CC BY 2.0

Principal Investigator

Dr Alan Woolley

Project summary

  • Focus: mineralisation and fluid processes that occur in carbonatitic magmas

We are investigating the mineralisation and fluid processes that occur in carbonatitic magmas in the Chilwa Alkaline Province of Malawi and the potential for extracting precious elements.

Carbonatites are economically important as they often have high concentrations of:

  • light rare earth elements (LREE)
  • niobium (Nb)

Most of the world's production of LREE and Nb minerals are extracted from carbonatite-related complexes.

Magmatic processes

When a carbonatite magma rises up and intrudes into Earth's crust, a number of reactions take place. During and after emplacement, fluids pass from the magma into the surrounding rocks, creating an aureole of altered rocks known as fenites. 

Fenitised zones are expected to have low concentrations of LREE and Nb because these elements are considered to be poorly mobile. 

Current research

We are comparing two contrasting carbonatites in the Chilwa Alkaline Province of Malawi.

Study of the fenitised zones has revealed:

  • LREE present at concentrations of up to 1,700ppm
  • Nb enrichment

This suggests that these elements can be mobile in carbonatitic fluids, and that fenite aureoles could be future exploration targets for low grade, large tonnage LREE mining.

Museum staff

  • Dr Alan Woolley
  • Emma Dowman

Collaborators

Carbonatite research

Museum scientists are studying carbonatites, igneous rocks composed of more than 50 weight percent calcium carbonate.

Projects:

Origins, evolution and futures research

We study the Earth's origins, environment and the evolution of life

Mineral and planetary sciences research

Investigating the origins and evolution of Earth and our solar system

Rock collection

The Museum’s rock collection consists of approximately 123,000 samples collected from around the world