1 x 2km Cretaceous magnesiocarbonatite intrusion (with minor ferrocarbonatite), apparently derived from primary carbonatitic mantle melt, intruded into Ordovician sediments. Located at approx 4,100 m elevation, 5km SW of the better-known Cerro Sapo carbonatite but (unlike Cerro Sapo) the Chiarake carbonatite has no visible relationship to nepheline syenite intrusion. Very low in silica (less than 1%); enriched in La-Ce-Nd-Sm (up to 1.3 wt%).
Ref: Matos, S.R. (2000) paper presented at XIII Congr. Geol. Bol. (La Paz).