Rare on the planet. Not common for large Nb (etc) deposits...

Rare on the planet. Not common for large Nb (etc) deposits especially in OZ but the exploration search for critical metals may alter that.

The listing below may only be a partial one and out of date at that.



2008 data with Seis Lagos at the bottom of list -alphabetical mainly??
Recent data for Seis Lagos gives:
Geophysical Research AbstractsVol. 16, EGU2014-12709-1, 2014EGU General Assembly 2014© Author(s) 2014. CC Attribution 3.0 License.

Mineralogical aspects of Morro de Seis Lagos deposit (Amazonas, Brazil).Lucy Takehara (1), Marcelo Almeida (2), and Francisco Silveira (1)(1) Brazilian Geological Survey, Mineral Resources Department, Brasília, Brazil, (2) Brazilian Geological Survey, GeologyDepartment, Manaus, Brazil

The alkaline body Morro dos Seis Lagos, situated in the northwest Amazonian region, is a Nb bearing depositformed by thick lateritic regolith as circular geological feature about 5 km in diameter. The host rock of thisdeposit is an intensely weathered siderite carbonatite. The alkaline intrusion body was formed during the lateMesozoic and enriched during the Cenozoic by process of denudation of the surrounding rocks and formation oflateritic cover with thickness in the order of hundreds of meters. In this process, enrichment of Nb, Fe, Ti, Mn, Pand rare earth elements (REE) occurred where the lateritic regolith represents the major Nb mineralization, withestimated inferred reserves of 2.9 billion ton@ 2.8 % Nb2O5, one of the largest deposits of Nb in the world. Themineralogical composition of the lateritic regolith has the predominance of the goethite and hematite, followedby oxy - hydroxides of Mn, Ti - Nb oxides, pyrochlore, cerianite and phosphates. The lateritic regolith samplesshowed high contents of Fe2O3 < 89.0%, TiO2 (< 12.54 %) and MnO2 (< 9.90 %). The goethite minerals showseveral generations that are related to different environmental conditions with dissolution and precipitation process,which indicate intense movement of the solutions with Fe in the aqueous medium. The main Nb minerals areilmenorutile, rutile and brookite where the ilmenorutile can have content up to 20 % Nb2O5. The P-rich minerals,like monazite and its alteration products, is the main REE phases. These minerals have high concentration ofCe2O3, La2O3 and Nb2O3, where ∑REE > 40 %, and is followed by elevated Th concentration, which locallyhas concentration higher than (18%). Another REE mineral is the cerianite. The main manganese minerals arehollandite, romanechite (BaMn9O16[OH4] - mixtures of manganese oxides) and amorphous Mn oxy – hydroxides.The higher concentration of MnO2 (about 40 %) is restricted to manganesiferous range, where manganese mineralsoccur as layers and filling voids, indicating strong remobilization by later process

Makes this bigger than Araxa! Inferred and no obvious recent work in the last 5 years or so - Sentinel.

Location Remote in upper amazon forests. In a biological reserve.

No sign of recent work on Google earth imagery.



Semi circular structure visible.