LASER ABLATION ICP-MS: WHEN THE RIGHT TOOL COMBINED WITH THE OTHER RIGHT TOOLS BECOMES EVEN MORE POWERFUL FOR ORE DEPOSITS (AND OTHERS) STUDIES (Invited Presentation)

Laser Ablation ICP-MS is well established in the geosciences (and now other fields) as the preeminent tool for trace element microanalysis. The number of examples of LA-ICP-MS with specific applications to even just ore deposits is too great to cover. The USGS has been involved in LA-ICP-MS of geological materials for over 20 years. With the development of better instrumentation, the challenges have been proper sample characterization prior to LA work and keeping up with data processing requirements and advancements. All too often LA-ICP-MS analyses are not fully integrated with other complimentary instrumentation and sample characterization methods. Complimentary information such as higher resolution SEM and/or x-ray maps are often overlooked when presenting LA-ICP-MS trace element data. Results from a variety of LA-ICP-MS applications to ore deposit studies will be presented with an emphasis on how integrated microanalysis utilizing SEM, electron microprobe, micro-XRF, Raman and other complimentary methods improve results. Examples of integrated textural, mineralogical, elemental and isotopic information for ore deposits will be presented. Mineral targets ranging from garnet and biotite to pyrite and other sulfides provide useful information about fluid conditions including oxidation state, isotopic source and sometimes (the hope) ore forming fluid chemistries. The full complement of trace elemental (and isotopic) information provided by LA-ICP-MS offers powerful tools for genetic information, possible vectoring to ore zone and new understanding of superimposed chemical signatures within a system. The role of careful quantification and reference materials development will also be described.