Evolution of hydrothermal regime along a crustal shear zone, Tinos Island, Greece

摘要

Structural cathodoluminescence and SIMS δ~(18)O analyses of quartz-calcite veins are combined to constrain the evolution in space and time of fluid infiltration in an exhuming detachment shear zone (Tinos Island, Cyclades, Greece). Careful description of vein arrays shows that the plumbing system evolved into an interconnected network just beneath the ductile-to-brittle transition. Microtextures of quartz and calcite infilling veins display deformed relics and newly precipitated grains. High-resolution δ~(18)O mapping in relics yields a steady quartz-calcite fractionation of 2 per thousand at ～ 400℃, whereas fractionation increases in neograins from 2 to 5 per thousand in 190 m toward the fault, or a ～ 150℃ temperature fall.