Low-temperature glass quenched from a synthetic, rare earth carbonatite; implications for the origin of the Mountain Pass Deposit, California

摘要: Synthetic carbonatite magmas are represented by melts in the system CaO-CO_2H_2O (Wyllie and Tuttle, 1960), relation between carbonatites and silicate has been investigated by addition of other components (e.g., Wyllie, 1966, 1978). We are presently determining phase relations a. series of systems involving CaO-CaF_2-La(OH)_3-CO_2-H_2O and other an effort to delineate the conditions for precipitation of rare earth carbonates and fluocarbonates (bastnaesite-type minerals) from synthetic magmas. As a supplement to construction diagrams characterized by limited numbers com portents, we have studied more complex bulk composition which we believe approximates that Sulphide Queen carbonatite at Mountain Pass, California-prior crystallization.