Investigations of granulite facies fluids prompted my more recent studies of the relations between metamorphism, deformation, and fluid movement. This work includes the examination of shear zones located in Southern Ontario and Northern New York. For example, I participated in a combined phase equilibria, fluid inclusion, and stable isotopic study of the Whitestone Anorthosite, a portion of which is located in the Parry Sound Shear Zone, Southern Ontario (collaborative work with D. Moecher, Univ. of Kentucky). These anorthosite samples contain texturally primary CO₂-rich fluid inclusions in plagioclase and garnet. However, these inclusions do not contain samples of the peak metamorphic fluid. Rather, the results from my study show that the fluid inclusions record late movement along the shear zone and may be used to constrain the retrograde P-T path. Thus, the examination of fluid movements along the Parry Sound shear zone provided some insight into the tectonic evolution of the region.

The results from the Parry Sound Shear Zone demonstrated that the densities of fluids in fluid inclusions recorded the P-T conditions during, or immediately after, dynamic recrystallization. I have also examined samples from other shear zones in the southern Grenville, including the Carthage-Colton mylonite zone (CCMZ) which is located in the Adirondack region of New York. Rocks from the CCMZ contain texturally primary CO₂-rich fluid inclusions that record late movement along the shear zone. The densities of the CO₂ in inclusions from the CCMZ, in conjunction with geothermometry, restrict retrograde P-T conditions. These results show that the retrograde P-T path differs markedly between two different areas of the Southern Grenville (the Parry Sound and Adirondack regions). Furthermore, deformation may have persisted along some high-grade shear zones well after the peak of metamorphism. These two results are probably related because retrograde motion along shear zones could result in differential unroofing of the various portions of the Southern Grenville province, and so explain differences in retrograde P-T paths.

These studies of the relations between deformation and metamorphism have led to more recent collaborative research. For example, we have been examining shear zones in core collected by the Ocean Drilling Program from the Southwest Indian Ridge. By combing microstructual observations with geothermometry on dynamically recrystallized pyroxenes we have been able to determine the temperatures, stresses, and strain rates of deformation. This information places constraints on geophysical models of the evolution of mid-ocean ridges. Additional collaborative research includes studies of mantle rocks.