A major problem posed by the geology of Crete is the horizontal contact of an upper unit without Miocene metamorphism onto a metamorphosed lower one with Early Miocene high pressure/low temperature (HP/LT) parageneses. This very sharp contact is roughly parallel to the major Oligo‐Miocene thrust planes which were reactivated as a large‐scale detachment which allowed exhumation of high‐pressure units. We describe the extensional deformation and the metamorphic evolution of the lower plate. Most first‐order deformation features relate to the retrogression from high‐pressure to low‐pressure conditions. A N‐S pervasive stretching is observed everywhere, often associated with a top‐to‐the‐north sense of shear. The extreme variation of thickness of the Phyllite‐Quartzite nappe (upper part of the lower plate) is probably the result of large‐scale boudinage similar to the one seen in large outcrops. The most important observation is the systematic occurrence of fresh carpholite immediately below the base of the Tripolitza nappe except in northwestern Crete where a late extensional shear zone is present. Deeper in the nappe pile carpholite is systematically retrograded. This observation reveals a drastically different PT history for the upper part of the Phyllite‐Quartzite nappe. It also suggests that the late extensional shear zone found along the northern side of Crete cuts inside the metamorphic structure and brings the nonmetamorphosed Tripolitza nappe directly in contact with the deeper parts of the Phyllite‐Quartzite nappe. PT‐t paths suggest a fast temperature decrease in the top of the Phyllite‐Quartzite during retrogression and, hence, during the top‐to‐the‐north shear. The deeper part of the Phyllite‐Quartzite nappe shows a low‐temperature regime throughout, but its PT path includes an isothermal decompression in the first stage. We produce a tentative map of domains having experienced similar PT trajectories during decompression. The overall cool regime is related to the continuous underthrusting of cola continental units during exhumation. Isothermal decompression observed in the core of the Phyllite‐Quartzite Nappe implies fast exhumation during extension and the faster cooling of the upper part is related to a continuous displacement toward the north of a cooler unit during exhumation. Single grain 39Ar‐40Ar ages obtained on phengites (15–25 Ma) in various structural sites are in good agreement with these conclusions and with the geological context suggesting that underthrusting of cold units at the front the accretionnary complex occurred contemporaneously with unroofing below a north dipping detachment near the top of the wedge. The age of this detachment is bracketed between the end of the high‐pressure event (20 Ma) and the deposition of the breccia (Early to Middle Miocene) in the Neogene basins.

Summary The central Aegean nappe pile can be readily related to that of the mainland Hellenides and has the advantage that the deeper levels are well displayed, particularly in the Cyclades. The following units can be distinguished, from base to top: (1) The para-autochtonous Ida or Talea Ori Sequence , recognized in Crete, Kassos, Rhodes (Lindos sequence) and Amorgos is, in part, a neritic carbonate platform sequence. It can be correlated with the Ionian-Preapulian autochthon of the mainland and most probably with the Menderes sequence of western Anatolia, there exposed in a tectonic window. (2) The major Tripolitza Nappe , a carbonate platform sequence, with the Phyllite Nappe at its base, is well represented in the outer arc as well as in Astypaleia and Santorini. (3) The Pindos and Arvi Nappes of Crete, Rhodes and Tilos are the remnants of an ocean basin active from Upper Triassic to Late Cretaceous times. (4) The Cycladic Blueschist Unit exposed on Syros, Siphnos, Naxos and other islands, occupies a tectonic position similar to the Pindos Nappe. It is interpreted as the subducted margin of the European plate, while the Pindos Nappe, the abyssal plain of the Apulian plate, was obducted just before continental collision in the Late Eocene-Oligocene. (5) The Asteroussia Nappe , composed of high-grade metamorphic rocks yielding cooling ages around 75 Ma, is present in Crete and in the Cycladic islands of Syros, Nikouria, Denoussa and Keros. It is interpreted as the remnants of a Pelagonian basement nappe, eroded in Miocene times. In the external or outer belt it has been thrust on to the unmetamorphosed Pindos Nappe but in the Cyclades it rests on the Cycladic Blueschist unit.

Meta-analytical approach was used to quantitatively synthesize the effect of immunocastration on growth, carcass, meat quality, reproductive organs and boar taint compounds. Altogether, 41 papers were collected for effect size (θ) calculation and the comparisons were made with entire males (EM) and surgical castrates (SC). The data for reproductive organs and growth performance are numerous enough to draw firm conclusions. In contrast, data for carcass and meat quality are more limited. Results of meta-analysis show efficient immunocastration with the magnitude of the response being by far the largest for reproductive organs (θ= −2.8 to −5.0) and boar taint substances (θ= −2.8 and −0.8 for androstenone and skatole, respectively). However, compared with SC, the immunocastrates exhibit larger bulbourethral glands (θ= 1.3) and slightly higher concentrations of androstenone and skatole (θ= 0.1 andθ= 0.2, respectively). The impact of immunocastration is also remarkable on performance, where the main advantage of the immunocastrates is their boar-like performance until revaccination. In the period following the second vaccination, they eat much more than EM (θ= 2.1), resulting in large effect size for growth rate compared with both EM and SC (θ= 1.1 andθ= 1.4, respectively). Considering the whole fattening period, their feed conversion ratio is higher compared with EM (θ= 0.6) and much lower than that of SC (θ= −1.3), although exhibiting moderately faster growth compared with both (θ= 0.6 andθ= 0.2, respectively). With regard to carcass quality, the immunocastrates take intermediate position between EM and SC. Besides, our analysis suggests no difference in meat quality with SC and some meat quality advantages of immunocastrates over EM because of higher intramuscular fat content (θ= 0.4) and lower shear force (θ= −0.6).

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