Arabia–Eurasia convergence is achieved in the NW Zagros by a combination of shortening on NW–SE-trending folds and thrusts, mainly in the Simple Folded Zone, and by right-lateral strike-slip on the NW–SE-trending Main Recent Fault. A balanced and restored cross-section across this part of the range indicates c . 49 km of shortening. This probably occurred since c . 5 Ma, providing an estimate of the long-term shortening rate across the Simple Folded Zone of c . 10 mm a −1 . The geometries of exposed structures suggest both basement thrusts and thin-skinned décollement levels, with major folds possibly nucleated above basement faults. Fold geometries indicate several décollement horizons; shale units are candidates, as well as evaporites in the Neogene, Mesozoic, Lower Palaeozoic and upper Proterozoic successions. The SE part of the Simple Folded Zone deforms by north–south shortening on broadly east–west-trending folds and thrusts. The link between these regions occurs via a set of fault blocks c . 400 km wide in total, each bounded by north–south right-lateral faults. Incremental changes in the strike of some of the folds occur across these right-lateral faults, with more east–west orientations to the east.

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Geochronological investigations in high-and ultra-high-pressure metamorphic rocks are problematic since ®rstly the low temperatures lead to ®ne grain size and disequilibrium assemblages, and secondly the problem of``excess argon'' aects 40 Ar-39 Ar systematics, the most commonly used isotopic system. The Tavsanli Zone is a belt of high-pressure low-temperature (HP-LT) rocks spanning NW Turkey and is one such region where previous geochronological studies have produced a range of estimates for the age of HP-LT metamorphism, raising the question of whether they are geologically signi®cant. This study presents new data from the Tavsanli Zone; 40 Ar-39 Ar ages are in the range 60 Ma to 175 Ma, whilst Rb-Sr ages are restricted to 79.7 Ma to 82.8 Ma, con®rming the presence of excess argon. Detailed ultra-violet laser ablation microprobe (UVLAMP) studies have revealed younger 40 Ar-39 Ar ages in the cores of coarser white micas, which in conjunction with 40 Ar-39 Ar ages from the ®nest grained lithologies and the Rb-Sr white mica crystallisation ages, constrain the post-HP-LT metamorphism exhumation rates of these rocks. Petrological and regional constraints suggest that syn-subduction exhumation and cooling took place initially by synchronous subduction and exhumation by underplating. This is followed by a phase of syn-continent-continent collision at a rate of approximately 1.5 mma A1 and exhumation to the surface via thrusting. The 40 Ar-39 Ar hornblende data from a granodiorite intruding the HP-LT rocks constrain the later parts of exhumation path. This study highlights the importance of a multi-system geochronological approach when attempting to determine the history of HP-LT rocks.