Crustal-scale geometry and kinematics of late-orogenic extension in the central Aegean (Cyclades and Ewia Island)
Crustal-scale geometry and kinematics of late-orogenic extension in the central Aegean (Cyclades and Ewia Island)
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爱琴海中部（基克拉泽斯和埃维亚岛）晚造山运动的地壳尺度几何和运动学
DOI：
10.1016/0040-1951(94)90066-3
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发表时间：
1994
期刊：
影响因子：
2.9
通讯作者：
J. Brun
中科院分区：
文献类型：
--
作者：
P. Gautier;J. Brun
爱琴海大陆域至少自中中新世以来就被认为是广泛的“弧后”延伸的地点，叠加了与中生代-新生代希腊造山运动相关的结构。早期逆冲作用造成的特征包括爱琴海两处遭受高压/低温变质作用的宽阔带内的整体延性变形。本研究总结了爱琴海中部地区（基克拉泽斯和埃夫维亚岛）的结构研究结果，特别研究了区域尺度上的延性变形和脆性变形之间的关系。延伸似乎是造成 HP 岩石单元内大部分延性变形的原因，这些岩石单元经历了穿透性绿片岩相和高级变质叠印。在所研究的每个岛屿上，通过发育至约 18-25 公里深度的主要正感脱离带，发生了渐进的伸展变形。考虑到区域尺度延性应变场的特征，描述了爱琴海中部尺度上的伸展系统的几何形状。至少确定了两个或三个近似平行的主要北倾脱离区，基克拉泽斯群岛西北部的走向为西北-东南走向，基克拉泽斯群岛东南部的走向为东西向，两者的初始倾角估计约为 30-45°。伸展系统目前的几何形状意味着这些脱离带和相关的变质核复合体相互干扰。考虑了两个主要的进化模型，它们可以解释平行分离区域之间的这种运动学联系。构造数据有利于合成主要分离区在与分离倾向方向相反的方向上顺序发展。研究区域的早期（渐新世-下中新世）脱离型伸展与造山晚期后增厚的“弧后”环境有关。
The Aegean continental domain is known to be the site of widespread “back-arc” extension since at least the Middle Miocene, overprinting structures related to the Mesozoic-Cenozoic Hellenic orogeny. Features attributed to early thrusting include the overall ductile deformation within two broad belts that have suffered HP/LT metamorphism across the Aegean. This study summarizes the results of a structural study in the central Aegean area (Cyclades and Evvia Island), examining in particular the relationship between ductile and brittle deformation on a regional scale. Extension appears to be responsible for most of the ductile deformation within HP rock units that have experienced penetrative greenschist-facies and higher-grade metamorphic overprinting. On each island studied, progressive extensional deformation has occurred through the development of a major normal-sense detachment zone down to depths of about 18–25 km. The geometry of the extensional system on the scale of the central Aegean is described, taking into account the characteristic features of the regional-scale ductile strain field. At least two-probably three-subparallel major north-dipping detachment zones are identified, trending NW-SE in the northwestern Cyclades and E-W in the southeastern Cyclades, both with initial dips estimated at around 30–45°. The present geometry of the extensional system implies that these detachment zones and related metamorphic core complexes interfere with each other. Two main evolutionary models are considered which can account for such a kinematic link between parallel detachment zones. Structural data favour the sequential development of synthetic major detachments zones in a direction opposite to the sense of dip of the detachments. Early (?Oligocene-Lower Miocene) detachment-type extension in the area studied is related to a late-orogenic post-thickening “back-arc” setting.