Mineralization characteristics and ore genesis of the light rare earth deposit in Taiping Town, western Henan

In western Henan Province, the rare earth ore deposit in Taiping Town is a newly-found medium-sized light rare earth deposit. Four orebodies were delineated in the three rare earth veins. The average thickness of the orebodies is 1.77 m, the average grade is 2.23 percent, the preliminary estimation of the amount of the resources is up to 100000 tons. Rare earth orebodies occur in the Mesoproterozoic plagiogranite and Erlangping Group, north of Taiping Town-Banshanping anticline, and are strictly controlled by NW-trending structures. The ∑ LREO accounts for 83.23%-99.35%, The ∑ HREO accounts for 16.77%-0.65%, and the distribution ratio of CeO₂+La₂O₃+Nd₂O₃ is 79.56%-94.15%. Rare earth mineral mainly is bastnaesite.The major rare earth minerals belong to the strongly selective partition pattern which is rich in LREE with feature of Ce > La > Nd. The rare earth ore reveals a depletion of light rare earth and enrichment of heavy one, with a weak positive Eu and indistinct Ce anomaly as well as distinct fractionation processes. The average ratio of Eu/Sm is 0.38; the ratio of Th/U is high, the indictation of magmatic origin is similar to bariterare earth distribution pattern. The veined light rare earth ores fill in the fault structures which formed in Yanshanian and were superimposed upon the Erlangping Group and Zhangjiazhuang rock mass. So the ore-forming epoch is not earlier than(108±1) Ma. The origin of the deposit belongs to the quartz vein and altered rock type, controlled by the crust-mantle mixed source and faulted structure. Exploration indicators include the filling materials composed of quartz vein and fluoritization baratization pyritization, altered rock, weak Th radioactive anomalies and low content of U. The results obtained by the authors are very important for theoretical research on rare earth minerals as well as prospecting and work deployment in Henan Province.