DETERMINATION OF RARE-EARTH ELEMENTS IN FLUID INCLUSIONS BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY (ICP-MS)

An inductively coupled plasma-mass spectrometer (ICP-MS) is used to de termine rare ear-th element (REE) abundances in fluid inclusions. Quar tz concentrates from the Bingham porphyry Cu-Mo deposit, Utah, USA, an d from a quartz vein in brecciated amphibolite dredged from the Mathem atician Ridge, an abandoned spreading center in the eastern Pacific, w ere prepared by a modified crush-leach method. Leachates and solutions from acid digestion of quartz residue from leaching were analyzed by ICP-MS, using conventional sample introduction. The results demonstrat e that the crush-leach method, followed by ICP-MS analysis of leachate s, is effective for REE determination. Chondrite-normalized REE patter ns for the Bingham samples are light rare earth element (LREE) enriche d, with a small negative Eu anomaly, and the pattern for the Mathemati cian Ridge sample is nearly flat, with a positive Eu anomaly.