Abstract Lithospheric thinning and crustal extension have shaped the Alpine orogen in western Anatolia since the late Oligocene, resulting in the denudation of one of Earth’s largest metamorphic core complexes, the Menderes Massif. We review locations and characteristics of geothermal fields and of Miocene mineral deposits in the context of crustal structure and geodynamic processes. Thermal spring locations show a close spatial association with active fault zones; the largest geothermal areas are located in the widest graben and at fault intersections, but show little relation to volcanic activity. During the first stage of tectonic denudation in the Miocene, epithermal, porphyry-type gold and structurally controlled base-metal deposits formed synchronously with K-rich volcanic and plutonic complexes in the northern Menderes Massif. Depositional environments favoured the formation of lignite, sedimentary uranium and borate deposits. Throughout this phase of extension in a hot continental setting, secondary porosity caused by brittle faulting of metamorphic basement rocks provided the key pathways for fluids and magmas. Although the Menderes Massif has remained in a similar position relative to active plate boundaries from the Miocene to the present, three significant changes in subcontinental mantle dynamics affected the nature of hydrothermal flow. First, the partial removal of lithospheric mantle changed the primary source component of magmatic rocks and metals from metasomatized lithosphere mantle to asthenospheric mantle. Secondly, surface uplift and progressive crustal extension led to segmentation of the Miocene land surface along NNE–SSW- and east–west-orientated fault zones, which changed the overall structural control on crustal permeability. Finally, hydrothermal flow changed from locally magmatic driven, to focused flow of topographically and thermally driven fluids in the crust, with high background heat flow caused by regional upwelling of the asthenosphere. The Menderes Massif is a continental tectonic domain that has experienced rapid thinning of lithospheric mantle and crustal extension in an overall convergent plate tectonic setting. The tectonic and geodynamic framework for evolving hydrothermal activity in western Anatolia may be applicable to other ore-forming systems in hot, extending continental crust in Earth’s history. Supplementary material: Supplement 1: Compilation of 124 thermal spring temperature measurements from Akkuş et al. (2005); Supplement 2: Compilation of 127 geothermal well temperature measurements from Akkuş et al. (2005) is available at https://doi.org/10.6084/m9.figshare.c.3803935

U-Pb dating of detrital zircons separated from paragneiss of the Myrsini Crystalline Complex of eastern Crete yielded peaks in 207 Pb/ 206 Pb ages at 0.6, 0.8, 1.0, 2.0, and 2.5 Ga. A striking Mesoproterozoic age gap is present between 1.1 and 1.6 Ga. The new data are compatible with U-Pb zircon ages derived from surrounding crystalline complexes of the Cyclades, the Menderes Massif, Egypt, and the Levant. Possible provenances of the zircons of the eastern Mediterranean domains are the Sahara meta-craton, the Arabian-Nubian Shield, and the Kibaran belt of central Africa. Because the age spectra of the eastern Mediterranean crystalline complexes differ significantly from those of the Cadomian- and Avalonian-type terranes, they are regarded as a separate collection of peri-Gondwanan terranes referred to as Minoan terranes. In late Neoproterozoic to ?Cambrian times, the latter underwent Andean-type orogeny at the northern border of East Gondwana, close to Egypt and the Levant. There is no evidence that the Minoan terranes traveled for long distances in Phanerozoic times.

The Western Anatolia extended terrane in Turkey is bounded by the North Anatolian fault zone to the north, the Lycian nappes to the south. It contains the Menderes massif, one of the post-collisional Alpine metamorphic core complexes. Field data and available radiometric ages suggest that the north-directed Cenozoic extension in the terrane is the product of three consecutive, uninterrupted stages, and that it is still continuing today. The first stage was initiated in the Late Oligocene along a north-dipping extensional simple-shear zone with a listric geometry at depth. The shear zone is named here as the Southwest Anatolian shear zone and marks the southern and southwestern boundary of the Western Anatolia extended terrane. Evidence for the presence of this shear zone includes (1) the dominant top to the north-northeast shear sense indicators in the Menderes massif and (2) a series of Oligocene extensional basins located adjacent to the shear zone that contain carbonate and ophiolitic rock clasts, but no high-grade metamorphic rock fragments. During this stage, erosion and extensional unroofing brought high-grade metamorphic rocks of the Central Menderes massif to the surface by the early Miocene. The second stage of extension produced the north-dipping Alasehir and the south-dipping Büyük Menderes detachment surfaces in the early Miocene. The detachments control the Miocene sedimentation in the Alasehir and Büyük Menderes grabens, containing high-grade metamorphic rock fragments that were already at the surface in the Central Menderes massif in the early Miocene. The third stage of extension may have started ca. 5 Ma, when the North Anatolian fault was initiated. This extensional phase produced faults within the Alasehir and Büyük Menderes grabens and possibly the Kucuk Menderes graben.