| Online link | https://doi.org/10.3133/ofr20091139 |
|---|---|
| Description | Data on 60 of the 527 known carbonatites in the world, providing reliable quantitative data on ore tonnages and grades of niobium and REE. |
| Originators | Berger, Vladimir I., Singer, Donald A., Orris, Greta J. |
| Publication | U.S. Geological Survey Open-File Report 2009-1139 |
| Metadata | Questions and answers |