Fluid inclusions: tectonic indicators

During the first half of the 20th century fluid inclusions have been studied in ore geology in order to determine the chemistry and physical parameters (density) of the mineralising fluids. Apart from a few pioneering works in the middle of the century, fluid inclusions were not used as structural markers before the late 1980s. During the same time, experiments as well as observations of natural samples have shown that the volume, shape and density of fluid inclusions may change when submitted to pressure–temperature conditions different from their trapping isochores. w of these experiments, and based on natural examples from the Higher Himalaya metamorphic rocks, it is evident how fluid inclusions can be used as thermobarometric, structural and tectonic markers. Points of interest for further studies on fluid inclusions in nature and experiments are also stressed.