Figure 6.

Field photographs and micrographs of quartz veins used for petrofabric analysis. Lines labeled 'walls' on micrographs indicate host rock‐vein orientation relative to photo. Yellow dashed lines indicate the interpretation of foliation generation and its orientation relative to the micrograph, and white dashed lines indicate orientation of the quartz shape preferred orientation (SPO). (a, b; zone 35°N, 254783°E, 4237525°N) Vein sample VS‐07B is isoclinally folded in outcrop with the gently W‐dipping macroscopic host foliation parallel to the axial plane. Recrystallized quartz within the vein shows an oblique SPO indicating top‐to‐ENE shear sense. Note similar sizes of subgrains in the rightmost quartz ribbon and surrounding finer grains. (c, d; zone 35°N, 250655°E, 4252375°N) Isoclinally folded vein sample VS‐10J shows alternating pinch‐ and‐swell of foliation‐parallel limbs and isoclinal folding of foliation‐normal hinges. Connecting segments of the vein are missing, perhaps due to pressure solution. Quartz shows an SPO parallel to the host foliation. Smaller grains show well‐defined grain boundary triple junctions. (e, f; zone 35°N, 245404°E, 4256238°N) Sample VS‐11F occurs as several disconnected segments. Quartz exhibits low‐amplitude bulging at grain boundaries and an oblique SPO consistent with top‐to‐NE shear sense. (g, h; zone 35°N, 254538°E, 4239847°N) Vein sample VS‐16C is an isolated pocket of quartz occupying the hinge of a NE‐SW trending fold in an outcrop preserving two axial plane cleavages. Quartz shows bulging and sutured grain boundaries. Green arrows indicate the approximate area shown in thin section. Abbreviations: blg: grain boundary bulging; ribbon: monocrystalline quartz ribbon; sg: subgraining; sgr: subgrain rotation. Scales sizes: pen in (a): 15 cm; 50¢ coin in (c, e): 24 mm diameter; pen in (g): 14.5 cm.