Fluid Inclusions

Applications of laser ablation ICP mass spectrometry in fluid inclusion research

PI: Ghazi, A. M., Dept. of Geology, GSU

The application of laser ablation as an alternative mode of sample introduction is a quite recent development that is of particular interest because it couples the sensitivity of ICPMS with ablating capabilities of a laser to allow direct analysis of solid samples without sample dissolution. However, the most challenging area in LA-ICPMS technology has been in developing calibration procedures for routine analysis. This is largely because of the lack of matrix matching since each different matrix interacts differently with the laser beam. This is particularly important in single fluid inclusion analysis where the unknown matrix is in a liquid state and most commonly used standards are in solid form (e.g, NIST glasses). The proposed project is a three-fold study to 1) build and evaluate a new simple (low cost) heating stage for homogenization of multi-phase (mineral-bearing) fluid inclusions, 2) to examine various calibration methodologies for analysis of single fluid inclusions and 3) to apply the most suitable technique to study four suites of well studied fluid inclusion samples. The calibration techniques include using: 1) the NIST glass reference materials 2) a set of new microcapillary-type artificial fluid inclusions containing a larger selection of elements in standard solution including the rare earth elements (REE), and 3) synthetic fluid inclusions containing known concentrations of specific elements.

A) Photomicrograph of a two-phase (liquid+vapor) fluid inclusion in halite from Palo Dura Basin, Texas. B) Photomicrograph of the emptied fluid inclusion showing irregular and enlarged opening of the laser hole, most likely caused by dissolution of host halite during ablation and uptake of the fluid from inclusion.

A. Mohamad Ghazi Department of Geology Georgia State University Atlanta, GA 30303 404-463-9556