Are fluid inclusion planes useful in structural geology?

Quantification of deformation or stresses in structural geology is often difficult due to the uncertainity of the paleodepth or fluid pressure. The best records of fluid percolation are paleofluids trapped as fluid inclusions in healed microcracks of the rock-forming minerals. Fluid inclusion planes (FIP) are mode I cracks which form in sets with a predominant orientation perpendicular to the least principle stress σ3. However, the repeated microfracturing and healing of the rock-forming minerals yield complex superimposed patterns of healed microcracks. Such patterns are often difficult to interpret due to the lack of suitable chronological criteria. These problems have been recently documented and solved by coupling deformation studies, detailed examination at all scales of the relationships between trapped fluids and their host structures, and studies of fluid inclusions. This paper summarizes recent advancements in FIP analysis and suggests further ways for research.