ABSTRACT
This chapter provides a brief introduction to fluid inclusions in general and microthermometry in particular. It outlines the values and limitations of fluid inclusions as tools for the petroleum geologist in evaluating the exploration and exploitation potential of a particular area. The chapter reviews the fluid inclusion evidence in support of a common provenance for oil and oil-forming fluids in sedimentary basins, with a brief discussion of the role of oilfield or basinal brines in base and precious metal ore formation. Fluid inclusions can occur in any naturally-formed or laboratory-grown crystal. The basic assumption that fluid inclusions are reliable indicators of the physical and chemical properties of geologic fluids is invalid if the inclusions have leaked or altered their volume in any way after trapping. Microthermometry is the most widely used, versatile, cost- and time-effective method of fluid inclusion analysis.
