Post-orogenic extension in back-arc regions is classically associated with metamorphic core complexes (MCCs) cored with exhumed metamorphic rocks and granitic intrusions interacting with low-angle detachments. When additional heat is provided by the advected asthenosphere below the extending region, for instance above slab tears, high-temperature migmatite-cored metamorphic domes and composite intrusions are emplaced whose geometry and kinematics of emplacement are controlled by regional extension and by detachments. The Cyclades Archipelago (Aegean Sea) hosts several such Miocene high-temperature MMCs intruded by Miocene granitoids, offering windows open on the interactions of intrusions with the Livada and Mykonos detachments, two branches of the North Cycladic Detachment System. Deformation associated with North Cycladic Detachment System has been described detailed on Mykonos based on a structural study of the deformation of the Mykonos pluton, but the high-temperature gneiss core of the MCC and the root zone of the intrusion have received little attention. Based on field surveys of the neighboring islands of Rheneia and Delos, we propose in this paper a new geological map and show that the locally migmatitic core of the MCC that extends from Rheneia to the Apollonia peninsula on Mykonos, is topped by a 500 m-thick low-angle shear zone, the Rheneia Shear Zone, coeval with the intrusion of a series of granitoids evolving from granodiorite to monzogranite. The Rheneia Shear Zone shows progressive flattening and shearing, with a constrictional component, during the intrusion of numerous fine-grained felsic dykes at various stages that are totally transposed to become parallel to the main regional foliation. The migmatitic core and the intrusion are intensely stretched with an E–W trending lineation and folds with axes parallel to the lineation. Structural compatibility between the migmatites and the intrusion show that the rheological parameters were not much different at the time of intrusion. The same deformation continued during cooling of the dome while new batches of granitic material intruded the colder gneiss. The granites show syn-kinematic stretching at the magmatic stage and after cooling, leading to full homoaxiality between the magmatic fabric and the mylonites below the Livada and Mykonos Detachment. From the stage of lower crustal partial melting and subsequent intrusion to mylonitization and formation of the brittle Mykonos detachment, deposition of the supra-detachment Miocene sediments and the late intrusion of baryte-iron dykes, the same kinematics is observed until a change in the stress regime some 9 Ma ago. The Mykonos-Delos-Rheneia MCC illustrates the continuous interactions between a detachment system and a growing pluton and how a discrete magmatic event can be influenced by long-term tectonics.

弧后地区的造山后扩张通常与变质岩心复合体（MCC）相关，MCCs以发掘出的变质岩和花岗岩侵入体与低角度脱离相互作用。当延伸区下方的平流软流层提供额外的热量时，例如在板状裂缝上方，则放置了以辉铁矿为核心的高温变质穹顶和复合侵入体，其侵入的几何学和运动学由区域延伸和脱离控制。基克拉迪群岛（爱琴海）拥有由中新世花岗岩侵入的中新世高温MMC，为入侵与北基克拉迪分离系的两个分支Livada和Mykonos支队之间的相互作用提供了窗口。基于Mykonos岩体变形的结构研究，已经在Mykonos上详细描述了与北基克拉迪拆离系统相关的变形，但是MCC的高温片麻岩芯和侵入的根区很少受到关注。根据对雷尼亚和德洛斯岛附近岛屿的实地调查，我们在本文中提出了新的地质图，并显示了从雷尼雅到米科诺斯岛上的阿波罗尼亚半岛的MCC局部地心岩心顶部是一个500 m-厚的低角度剪切带，Rheneia剪切带，与一系列从花岗闪长岩到辉长花岗岩演化的花岗岩类的侵入并存。Rheneia剪切区显示逐渐变平和剪切，并有收缩成分，在许多不同阶段的无数细粒长相岩入侵期间，这些长相岩完全转变为与主要区域叶脉平行。今朝的岩心和侵入岩被一条E-W趋势线强烈拉伸，并以平行于该线轴的方向折叠。蒙脱石与侵入岩之间的结构相容性表明，侵入时的流变参数差异不大。在穹顶冷却期间，相同的变形继续进行，而新一批的花岗岩材料侵入了较冷的片麻岩。花岗岩在岩浆阶段和冷却后表现出同运动学拉伸，导致岩浆织物与Livada和Mykonos支队以下的髓鞘之间完全同轴。从下地壳部分熔融和随后的侵入阶段，到髓系化和脆性米科诺斯分离的形成，超分离中新世沉积物的沉积以及重质铁堤的晚期侵入，观察到相同的运动学直到应力发生变化。政权大约在9 Ma以前。Mykonos-Delos-Rheneia MCC说明了分离系统和不断增长的岩体之间的持续相互作用，以及离散的岩浆事件如何受到长期构造的影响。