Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey
Exhumation with a twist: Paleomagnetic constraints on the evolution of the Menderes metamorphic core complex, western Turkey
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扭曲的折返：古地磁对土耳其西部门德雷斯变质核杂岩演化的限制
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发表时间：
2010
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通讯作者：
Marijn Koopman
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作者：
D. V. van Hinsbergen;M. Dekkers;E. Bozkurt;Marijn Koopman
关于区域垂直轴旋转、大陆伸展和缩短之间的联系，还有许多问题有待了解。在土耳其西部，中新世的垂直轴旋转与门德雷斯变质核杂岩的伸展折返同时发生，这与爱琴海弧后东部的弧后伸展有关。在本文中，我们探讨了土耳其西南部的垂直轴旋转和Menderes地块的伸展去顶之间的时空关系。为此，我们提供了大量来自土耳其西部的新古地磁数据，并将这些数据与区域构造演化相结合，以测试爱琴海地区向斜弯曲的原因和后果。Lycian推覆体和Bey Daeurlalanes在16 ~ 5 Ma之间旋转了约20°，确定了爱琴海造山带的东翼。这发生在同一时期的中央Menderes地块的折返（沿着伸展dettension）和后的最新渐新世早中新世折返的北方和南部Menderes地块。后两者的折返与垂直轴旋转无关。从莱斯沃斯岛到乌伊萨克，在门德里斯地块中部以北的中新世晚期火山岩经历了一个小的顺时针旋转，相对于欧亚大陆来说微不足道。这表明，中央Menderes地块的折返与北方和南方Menderes地块之间的垂直轴旋转差异为25°-30°有关。这一结果与Büyük Menderes和Alaehir断层走向所定义的角度以及横跨Menderes地块中部的区域弯曲拉伸线理图案所定义的角度非常一致。这些结构定义了西安纳托利亚旋转的枢轴点（旋转极点）。南部区域的旋转，包括南部的曼德列斯地块、吕西亚推覆体和贝达拉马尔，一定导致了该极以东的南北向收缩。伊斯帕尔塔角中心的阿克苏逆冲断层与克尔卡瓦克断裂的扭压耦合作用构成了旋转域的东界。先前报道的阿菲永附近火山区的顺时针旋转可能是枢轴点以东分布的南北缩短的结果。这种缩短的历史的确切适应性仍然有待调查。晚渐新世至早中新世的延伸在爱琴海弧后的东部是东北-西南方向，并可能有边界的离散转换。这一转变可能与爱琴海东部俯冲转变边缘传播断层的早期演化有关。在西安纳托利亚地区的造山带弯曲可能与爱琴海造山带东部与非洲向北移动的板块在爱琴海后弧卷回，相当于最近假设的情况下，希腊西部的重新连接。
Much remains to be understood about the links between regional vertical axis rotations, continental extension, and shortening. In western Turkey, Miocene vertical axis rotations have been reported that occur simultaneously with the extensional exhumation of the Menderes metamorphic core complex, which has been related to back‐arc extension in the eastern part of the Aegean back arc. In this paper we explore the spatial and temporal relationships between vertical axis rotations in southwestern Turkey and extensional unroofing of the Menderes Massif. To this end, we provide a large set of new paleomagnetic data from western Turkey, and integrate these with the regional structural evolution to test the causes and consequences of oroclinal bending in the Aegean region. The Lycian Nappes and Bey Dağları are shown to rotate ∼20° between 16 and 5 Ma, defining the eastern limb of the Aegean orocline. This occurred contemporaneously with the exhumation of the central Menderes Massif (along extensional detachments) and after the latest Oligocene to early Miocene exhumation of the northern and southern Menderes massifs. Exhumation of the latter two was not associated with vertical axis rotations. The lower Miocene volcanics in the region from Lesbos to Uşak, to the north of the central Menderes Massif underwent a small clockwise rotation, insignificant with respect to Eurasia. This shows that exhumation of the central Menderes Massif was associated with a vertical axis rotation difference between the northern and southern Menderes massifs of ∼25°–30°. This result is in excellent agreement with the angle defined by the trends of Büyük Menderes and Alaşehir detachments, as well as the angle defined by the regionally curving stretching lineation pattern across the central Menderes Massif. These structures define a pivot point (rotation pole) for the west Anatolian rotations. The rotation of the southern domain, including the southern Menderes Massif, the Lycian Nappes, and Bey Dağları, must have led to N–S contraction east of this pole. The eastern limit of the rotating domain is formed by the transpressional couple of the Aksu thrust and Kırkkavak Fault in the center of the Isparta angle. Previously reported clockwise rotations in the volcanic fields near Afyon may be the result of distributed N–S shortening east of the pivot point. The precise accommodation of this shortening history remains open for investigation. Late Oligocene to early Miocene extension in the eastern part of the Aegean back arc was NE–SW oriented and likely bounded by a discrete transform. This transform may be associated with an early evolution of the eastern Aegean subduction transform edge propagator fault. Oroclinal bending in the west Anatolian region is likely related to a reconnection of the eastern part of the Aegean orocline with the African northward moving plate in tandem with roll back in the Aegean back arc, comparable to a recently postulated scenario for western Greece.