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 determine rare ear-th element (REE) abundances in fluid inclusions. Quartz concentrates from the Bingham porphyry Cu-Mo deposit, Utah, USA, and from a quartz vein in brecciated amphibolite dredged from the Mathematician Ridge, an abandoned spreading center in the eastern Pacific, were 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 demonstrate that the crush-leach method, followed by ICP-MS analysis of leachates, is effective for REE determination. Chondrite-normalized REE patterns for the Bingham samples are light rare earth element (LREE) enriched, with a small negative Eu anomaly, and the pattern for the Mathematician Ridge sample is nearly flat, with a positive Eu anomaly.