Timing of tectonic events in the Menderes Massif, Western Turkey - Implications for tectonic evolution and evidence for Pan-African basement in Turkey
Timing of tectonic events in the Menderes Massif, Western Turkey - Implications for tectonic evolution and evidence for Pan-African basement in Turkey
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土耳其西部门德雷斯地块的构造事件时间——对构造演化的影响和土耳其泛非基底的证据
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发表时间：
1984
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通讯作者：
R. Akkök
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作者：
A. Şengör;M. Satır;R. Akkök
门德里斯地块形成了土耳其阿尔卑斯造山带内两个大型变质顶点的西部。它有三个主要的岩性单位，在基地片麻状的“核心”和“片岩”和“大理石”信封依次覆盖它，虽然它们之间的关系已在很大程度上被掩盖的多变质和结构复杂的历史地块。我们提出了一个审查现有的地层证据和联合收割机，它与新的同位素年龄从中部和南部的地块，以限制时间的主要构造事件，形成地块自晚元古代（Pt 3）。在地块的南部（严格意义上）有三个变形和变质阶段，而在其北方则有四个。第一幕发生在−500 ± 10 Ma，在高级角闪岩相发生强烈变形变质作用，并伴有局部深熔作用。在地块的中部，470 ± 9 Ma的高度变形的英云闪长质和花岗岩侵入体标志着这一幕的结束。在地中海东部大陆的寒武纪重建中，曼德列斯地块形成了非洲东北部和阿拉伯半岛的泛非造山拼贴的南端。最早的古生代变形在曼德列斯地区可能与西北非洲造山拼贴沿着走向通过Bozburun和Saricicek辉绿岩，arkoses，和片岩在卡拉恰希萨尔圆顶的中心，在这里解释为泛非缝合的片段。影响岩石的最早古生代变形可能与最后的泛非碰撞和相关的碰撞后会聚有关。地块南部从早奥陶世到早（？北方可能在晚三叠世发生变形、变质和侵入，与古特提斯卡拉卡亚边缘盆地的闭合有关。影响整个地块的下一个主要事件是强烈的变形和广泛的变质作用，在结构较低的部分达到高角闪岩级，在最外层的信封只有绿片岩级。这种变质作用，在这里被称为“主门德里斯变质作用”（MMM），是生物地层之间的早始新世和早渐新世的时间限制。Rb/Sr同位素数据显示年龄分布在60 Ma和25 Ma之间，最大数量的测定约为35 ± 5 Ma。这一数字与地层学证据非常吻合，表明MMM发生在始新世末或始新世至渐新世的过渡时期。沿着地块的北方边界，变形和变质作用在晚白垩世已经在高压/低温（HP/LT）变质带（广义上的Menderes地块的最北部）发生，然后被古新世磨拉石覆盖。HP/LT带的演化可能与博兹基尔蛇绿岩从新特提斯洋的伊兹密尔-安卡拉分支的仰冲作用有关，并先于地块演化的终端碰撞。MMM是最新的古新世碰撞横跨新特提斯和随后的内部叠瓦的Menderes-Taurus块体，导致在Menderes地块下的Lycian推覆体复杂的埋葬面积的产物。一个低级变质事件，在10至5马被解释为有关的伸展变形在爱琴海和土耳其西部，这已被定年地层已开始在Tortonian（11.5马）。
The Menderes Massif forms the western of the two large metamorphic culminations within the Turkish Alpide orogen. It has three major lithologic units, with a gneissic “core” at the base and a “schist” and a “marble” envelope overlying it successively, although relations between them have been largely obscured by the polymetamorphic and structurally complex history of the Massif. We present a review of the available stratigraphic evidence and combine it with new isotopic ages from the central and southern parts of the Massif to constrain the timing of major tectonic events that shaped the Massif since the late Proterozoic (Pt3). In the southern part of the Massif (sensu stricto) three episodes of deformation and metamorphism are distinguished, whereas in its northern part there are four. The first episode occurred at −500 ± 10 Ma with intense deformation and metamorphism at high grade amphibolite facies with local anatexis. In the central part of the Massif, the 470 ± 9 Ma-old now highly deformed tonalitic and granitic intrusions mark the end of this episode. On a Cambrian reconstruction of continents around the eastern Mediterranean, the Menderes Massif forms the southern end of the Pan-African orogenic collage of northeastern Africa and Arabia. The area of earliest Palaeozoic deformation in the Menderes may connect with the northwest African orogenic collage along the strike via the Bozburun and Saricicek diabases, arkoses, and schists in the center of the Karacahisar dome interpreted herein as fragments of a Pan-African suture. The earliest Palaeozoic deformations to affect the rocks were probably related to the last Pan-African collisions and associated postcollisional convergence. The southern part of the Massif was undeformed from early Ordovician to the early (? later) Eocene, whereas the northern part was deformed, metamorphosed and intruded possibly during the late Triassic, related to the closure of the Karakaya marginal basin of Palaeo-Tethys. The next major event affecting the whole of the Massif was the intense deformation and widespread metamorphism that reached high amphibolite grade in the structurally lower parts, and only greenschist grade in the outermost envelope. This metamorphism, here called the “main Menderes metamorphism” (MMM), is biostratigraphically constrained between early Eocene and early Oligocene time. Rb/Sr isotopic data show a spread of ages between 60 Ma and 25 Ma, with the greatest number of determinations around 35 ± 5 Ma. This number is in excellent agreement with the stratigraphic evidence and shows that MMM took place during latest Eocene time or at the transition from Eocene to Oligocene time. Along the northern border of the Massif, deformation and metamorphism had already taken place during the late Cretaceous in a high pressure/low temperature (HP/LT) metamorphic belt (northernmost part of Menderes Massif sensu lato), which was then covered by Palaeocene molasse. The evolution of the HP/LT belt was probably related to the obduction of the Bozkir ophiolites from the Izmir-Ankara branch of the Neo-Tethys ocean and preceded terminal collision in the evolution of the Massif. The MMM was a product of the latest Palaeocene collision across Neo-Tethys and the consequent internal imbrication of the Menderes-Taurus block that resulted in the burial of the Menderes Massif area beneath the Lycian nappe complex. A low grade metamorphic event dated at 10 to 5 Ma is interpreted to be related to the extensional deformation in the Aegean and western Turkey, which has been dated stratigraphically to have begun during the Tortonian(11.5 Ma).