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Geoquímica e mineralogia dos elementos terras raras no depósito de nióbio de seis lagos (Amazonas): avaliação preliminar do potencial para explotação como subprodutos
| Content Provider | Semantic Scholar |
|---|---|
| Author | Bidone, Mauricio Harm |
| Copyright Year | 2015 |
| Abstract | The iron carbonatite of Seis Lagos underwent through intense fluidization rich in rare earth elements (REE), altering and generating a laterite cover which sustains the hill’s relief, and which reaches in some parts a thickness of 250 m. CPRM confirmed the existence of the greatest Nb deposit ever found in the world associated with this laterite, and also found the existence of anomalous concentrations of rare earth elements. The Morro de Seis Lagos has three different geological settings, the first is the carbonatite itself and its altered form, that in this work is called carbonate breccia. The second is the lateritic crust that forms the Nb ore and has an average of 1.75% of ETR2O3, mostly in the form of cerianite ((Ce, Th) O2). The third is represented by a basin of karstic origin, named Bacia Esperança by CPRM, where this company encountered anomalous concentrations of REE. In the current work there were detected ETR2O3 levels up to 3.1%, and an average of 1.68% through the entire Bacia Esperança, concentrated in the form of florencite (CeAl3 (PO4) 2 (OH) 6), which exceeds CPRM’s expectations on the reservation. It was recognized in Seis Lagos , besides cerianite and florencite, as ETR minerals, monazite ((Ce, La, Nd, Th, Ca) PO 4), bastnaesite (Ce (CO3) F), thorbastnaesita (Th (Ca, Ce) (CO3) 2F2 * 3 (H2O)). Among those, florencite and cerianite are characterized by being light rare earth elements (LREE) ores. Although monazite presents high cerium (Ce) concentration, its quantity in the deposit is not suitable to define a mineral ore. In addition to the REE minerals, it was found minerals bearing these elements, such as pyrochlore ((Ca, Na) 2 (Nb, Ti, Ta) 2 O 6 (OH, F, O)) and gorceixita (BaAl3 (PO 4) (PO3OH) ( OH) 6. The pyrochlore is the mineral that best represents the alteration evolution within the deposit, and it was possibly the mineral which provided the ETR to the system. The carbonatite Seis Lagos has higher concentrations of heavy rare earth elements (HREE) than the other lithologies of the deposit, and that opens the possibility for these elements to have been remobilized similarly to the Mount Weld deposit (Australia) and to have concentrated at the base of lateritic crust, where the drills have not reached. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.lume.ufrgs.br/bitstream/handle/10183/132009/000982577.pdf?sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
