Other Analytical Approaches
The previous chapters have dealt with the theory and practice of conducting fluid inclusion studies in the diagenetic realm by concentrating on petrographically based approaches that should be readily accessible to all researchers. This chapter concentrates on other analytical approaches that may be applied in a fluid inclusion study to constrain further the composition of fluid inclusions. A few laboratories conduct these types of analyses as the initial part of a fluid inclusion study, and such an approach may prove to be worthwhile for oil and gas exploration. However, in a fluid inclusion study that places fluid inclusion origins into a paragenetic and geologic context, and that involves microthermometric analysis, these analytical techniques will be applied only for specific purposes that arise during the course of a petrographically based study. As the application of these additional analyses requires equipment that will probably not be available in every laboratory, each technique will not be treated in detail: the utility of a range of analytical techniques is only summarized. Most of these techniques are still in developmental stages, so successful utilization will probably require commitment of time and sufficient funding for continued development.
Of the analytical approaches available, no single technique can provide a complete analysis of all of the components in a fluid inclusion. Each technique has its strengths and weaknesses in terms of components that may be analyzed and the concentrations and amounts required. A single fluid inclusion may need to be studied by a variety of analytical techniques to answer a compositional question posed. Thus, it is important to know something of the capabilities of the entire arsenal of analytical tools and approaches that can be used.
Figures & Tables
The past decade has revealed significant advantages to using fluid inclusions as a means of understanding the physical and chemical history of fluids in sedimentary basins, but it also has revealed important limitations which have required that a new approach must be employed to effectively use fluid inclusions. This book is divided into six sections: (1) what fluid inclusions are and what geologic history they are capable of recording; (2) basic phase equilibria that must be known to understand the behavior of pore fluids and fluid inclusions in nature; (3) the question of validity of using fluid inclusions as records of ancient diagenetic systems is dealt with in such a way that the questions commonly asked about the limitations of the technique are addressed; (4) hot to conduct a fluid inclusion study, a new petrographically based approach for conducting fluid inclusion research that is followed by methods that allow for the interpretation of compositions of pore fluids that existed in sedimentary rocks, and methods of geothermometry and geobarometry; (5) selected case histories that are designed specifically to give practice in evaluating fluid inclusion data from the diagenetic realm; and (6) a summary of the arsenal of analytical techniques that may be applied to fluid inclusions to develop additional constraints on fluid inclusion composition.