『Abstract
The Bayan Obo Fe-REE-Nb deposits is the world's largest rare
earth element (REE) resource and its genesis has been the subject
of much debate for many years. The most popular are the carbonatite-related
and hydrothermal Fe oxide-Cu-Au-(REE-U) genetic models. Comparisons
of geologic setting, lithology, mineral assemblages, metal associations,
geochemistry (particularly REE and light REE/heavy REE ratios),
fluid chemistry and isotopics indicate that the Bayan Obo deposit
shares features of both types, which are classified differently;
that is, the carbonatites model is host-rock based, while the
Fe oxide-Cu-Au-(REE-U) model is essentially mineral assemblage
and metal association based. A speculative classification scheme
is tentatively put forward to link the two models, but many questions
remain for further studies.
Keywords: Bayan-Obo; carbonatites; iron oxide Cu-Au; ore genesis;
rare earths』
1. Introduction
2. Comparison with carbonatite deposits
3. Comparison with Fe-oxide-Cu-Au-(REE-U) family deposits
4. Speculative classification model
Acknowledgments
References