Quartz Vein Geochemistry Records Deformation Processes in Convergent Zones

In several examples of subduction zones, we compared pairs quartz veins formed either at the lower temperatures seismogenic zone (260°C or below), higher its downdip limit (∼330°C). All analyzed here are mode I cracks that contemporaneously with host-rock main stage deformation peak burial conditions. Lower-temperature show crystals euhedral shapes and growth rims, while higher-temperature contain crack-seal microstructures. lower-temperature realm, rims have alternatingly either: (1) high cathodoluminescence (CL), CL-blue color concentration in trace elements fluid inclusions, (2) low luminescence, CL-brown inclusions. contrast, from samples is homogeneously luminescent CL-brown, except for very restricted domains microstructures where patches present. The highly contains concentrations aluminum lithium, up to 3,000 400 ppm, respectively. Variations Al Li correlate well, so appears as charge-compensating cation Al. We propose incorporation reflects amplitude pressure variations, which control crystal rates. Quartz geochemistry might therefore unravel contrast between zone, large variations present, limit, much more limited amplitude.