LevyOdlum_CIG Tectonics_Apatite.pdf

Apatite grains from the Saint Barthelemy Massif (Northern Pyrenees) are investigated to understand U-Pb and trace element systematics during crystal plastic deformation. Electron backscatter diffraction of individual grains was employed to measure crystal plastic deformation. Grains from the footwall mylonite zone record evidence of crystal plastic deformation expressed as intragrain misorientation across low-angle boundaries. Crystallographic orientation data indicate slip along the [100] plane in the <001> direction, which is consistent with previously investigated slip systems in apatite. These results suggest dislocation creep is the primary deformation mechanism. Similar deformation patterns observed in zircon are shown to facilitate Pb diffusion out of the crystal lattice. This may be the case in deformed apatite, however further study is required to confirm this phenomenon.