Along-strike variations in the Hellenide-Anatolide orogen: a tale of different lithospheres and consequences

Περίληψη

Structure and exhumation history of the Hellenide-Anatolide Orogen in the Aegean Sea region and the adjacent Anatolian peninsula is controlled by along-strike variations of pre-Alpine palaeogeography. In the Hellenides, Mesozoic extension created ribbon-like continental fragments of thinned and dense lithosphere that pinch out eastwards. In the east, the relatively large Anatolide microcontinent mostly escaped Mesozoic extension and lithospheric thinning, presumably because it had a distinctly different, thicker and more depleted lithosphere. In the Aegean transect these alongstrike differences in lithosphere structure ultimately resulted in sustained highpressure metamorphism followed by progressive slab retreat since about 60 Ma. Further east, collision of the Anatolide microcontinent at about 42 Ma formed a south verging greenschist-facies thrust-and-fold belt. Pronounced slab retreat in the Aegean forced differential extension resulting in a broad sinistral wrench corridor that started to from at 24-23 Ma. Since then, extension in both regions mainly controlled denudation. This review highlights how differences in pre-orogenic architecture control lithospheric thickening and the subsequent exhumation of high-pressure rocks, and how large-scale continental extension evolves.