Fluid inclusions: tectonic indicators

During the first half of the 20th century fluid inclusions have been studie d in ore geology in order to determine the chemistry and physical parameter s (density) of the mineralising fluids. Apart from a few pioneering works i n the middle of the century, fluid inclusions were not used as structural m arkers before the late 1980s. During the same time, experiments as well as observations of natural samples have shown that the volume, shape and densi ty of fluid inclusions may change when submitted to pressure-temperature co nditions different from their trapping isochores. In view 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 f or further studies on fluid inclusions in nature and experiments are also s tressed. (C) 1999 Elsevier Science Ltd. All rights reserved.