Description
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AMIS0356 REO carbonatite Tanzania
Origin of Material: AMIS0356 is a commissioned CRM made up of material supplied by Montero Resources Ltd. from the Wigu Carbonatite Complex located 200km WSW of Dar es Salaam. Wigu Hill is underlain by Paleoproterozoic metasediments consisting of well foliated high grade gneisses and amphibolites. These rocks have been intruded by a swarm of carbonatite dykes on the southern edge of the Uluguru Mountains where the Uluguru massif is truncated by a major Karoo aged rift. The intrusions have resulted in strong carbonate alteration of the gneisses and amphibolites adjacent to the dykes and a more pervasive fenitisation and weaker carbonate alteration halo away from the dykes.
Mineral and Chemical Composition: The carbonatite material selected for this sample is fresh, compact and tightly and finely crystalline. It is bastnasite-rich with minor amounts of synchisite, parasite and monazite, with traces of apatite. The carbonatite is dolomitic with a significant proportion of Rare Earth Oxide minerals (REO’s) and lesser associated quartz, barite, strontianite, iron oxides and minor manganese.
Regional sampling to date has identified that the main rare earth minerals present in the Wigu carbonatites are the light rare earths, namely Cerium, Lanthanum, Neodymium, Praseodymium, and Samarium. Minor amounts of Europium and Gadolinium are present, but the other heavy rare earth elements are present in trace amounts only.
Recommended Concentrations and Limits
(at two Standard Deviations)
Certified Concentrations
Ce FUS 1.116 ± 0.0705 %
Dy FUS 13 ± 1.5 ppm
Eu M/ICP 29 ± 2.1 ppm
La FUS 8533 ± 731 ppm
Nd FUS 2482 ± 171 ppm
Nd M/ICP 2419 ± 240 ppm
Pr FUS 942 ± 73 ppm
Sm FUS 159 ± 12 ppm
Sm M/ICP 159 ± 10 ppm
Sr FUS 1.848 ± 0.127 %
Sr M/ICP 1.803 ± 0.131 %
Th FUS 84 ± 7 ppm
Th M/ICP 84 ± 10 ppm
Tm M/ICP 0.31 ± 0.04 ppm
U FUS 4.3 ± 0.5 ppm
U M/ICP 4.2 ± 0.5 ppm
Y FUS 35 ± 4 ppm
Specific Gravity 2.99 ± 0.20
Provisional Concentrations
Dy M/ICP 12.8 ± 2.9 ppm
Eu FUS 29.7 ± 3.6 ppm
Ho FUS 1.7 ± 0.4 ppm
Ho M/ICP 1.6 ± 0.3 ppm
La M/ICP 8226 ± 1066 ppm
Nb FUS 214 ± 42 ppm
Pr M/ICP 894 ± 169 ppm
Sc M/ICP 28 ± 6 ppm
Y M/ICP 35 ± 5 ppm
Indicated Means
Er FUS 2.9 ppm
Er M/ICP 3.2 ppm
Gd FUS 72.5 ppm
Gd M/ICP 58 ppm
Lu FUS 0.24 ppm
Lu M/ICP 0.28 ppm
Nb XRF 166 ppm
Nb M/ICP 173 ppm
Tb FUS 5 ppm
Tb M/ICP 4 ppm
Tm FUS 0.32 ppm
Y XRF 27 ppm
Yb FUS 1.9 ppm
Yb M/ICP 1.9 ppm
