STRATIGRAPHY OF THE PAN – AFRICAN BASEMENT OF THE MENDERES MASSIF AND THE RELATIONSHIP WITH LATE NEOPROTEROZOIC/CAMBRIAN EVOLUTION OF THE GONDWANA
STRATIGRAPHY OF THE PAN – AFRICAN BASEMENT OF THE MENDERES MASSIF AND THE RELATIONSHIP WITH LATE NEOPROTEROZOIC/CAMBRIAN EVOLUTION OF THE GONDWANA
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门德雷斯地块泛非基底地层及其与冈瓦纳新元古代晚期/寒武纪演化的关系
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发表时间：
2011
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通讯作者：
Roland Oberh Kaya
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作者：
O. Candan;O. Dora;Roland Oberh Kaya
Menderes地块位于安纳托利亚西部，在构造上位于北部的阿菲永带和南部的吕西亚推覆体之上。在西北部，两个高压单元，基克拉迪杂岩和上覆的利西亚推覆体，以及伊兹密尔-安卡拉地区的推覆体在构造上覆盖了门德雷斯地块。该地块的变质岩系可分为两个主要单元：1-泛非基底（核系）和2-古生代-早第三纪变质沉积岩（盖层系）。* Dokuz Eylul大学工学部土耳其布卡/伊兹密尔地质工程学院Muhendislik 35160号（osman. deu.edu.tr）** Institut fur Erdund Umweltwissenschaften，Universitat波茨坦，Karl Liebknecht Str. 24，波茨坦14476，德国。*Eberhard-Karls-Universitat Tubingen，Institut fur Mineralogy，Petrologie und Geochemie，Lehrstuhl fur Geochemie，Wilhelmstrasse，56，72074 Tubingen，德国 * 中国科学院地质与地球物理研究所，邮政编码：北京9825信箱，100029-中国 * 2002年5月22日去世，工程系。泛非基底的地层由部分混合岩化变质碎屑岩序列和侵入这些变质碎屑岩中的多变质基性和酸性火成岩组成。这一变质碎屑岩序列由副片麻岩和整合上覆的片岩单元组成，最小厚度为8公里，形成了门德雷斯地块泛非基底最古老的岩石。野外研究和年代学资料表明，副片麻岩的原岩主要是岩屑砂岩成分的碎屑沉积物。副片麻岩与分别来自泥岩和次长石砂岩的云母片岩和黑云母-钠长石片岩在各个方向上交替交错。副片麻岩整合覆盖在一个片岩单元之上。原来逐渐沉积接触是由副片麻岩和片岩夹层代表。片岩以云母片岩为主，夹有黑云母-钠长石片岩层，分别来源于泥岩和次长石砂岩。在Menderes地块，副片麻岩一般广泛混合岩化。广布的深熔花岗岩呈不规则体产出，边缘有混合岩化。副片麻岩的碎屑锆石年龄分布在610 ~ 2558 Ma之间。泛非基底片岩单元的碎屑锆石年龄为592 - 3239 Ma。与变质层序有明显侵入接触关系的正片麻岩的侵入时代为570 ~ 520 Ma。副片麻岩单元麻粒岩相变质年龄为583± 5.7Ma。这些地质年代学证据和接触关系清楚地表明，泛非基底变质层序原岩的沉积时代可以被限制在新元古代晚期之间约590 - 580 Ma。变质堆积序列被大型花岗岩体和辉长岩株侵入。花岗岩类前体的侵入年龄为520 ~ 570 Ma，主要事件发生在550 Ma左右，以矿物成分和原生结构发生变化的正片麻岩为代表。这些花岗岩可分为三大类（黑云母正片麻岩、角闪石正片麻岩和电气石浅色正片麻岩），是侵入变质层序的多期泛非酸性岩浆活动的产物。它们是泛非造山带的同变质后侵入体。泛非基底中的基性变火成岩具有辉长岩到绢英质的成分。它们显示出巨大的核和叶理边缘，主要由石榴角闪岩和榴辉岩遗迹组成，揭示了泛非基底的多变质历史。现场证据和放射性年龄数据表明，泛非基底和古生代盖层之间的主要接触关系在Menderes地块是一个不整合（超泛非不整合）和盖层来源于泛非基底。泛非基底的副片麻岩和片岩的原岩沉积在新元古代晚期（莫桑比克洋）发生在东西冈瓦纳之间的盆地的被动大陆边缘。泛非基底获得的所有岩浆和变质年龄均与新元古代晚期该海洋的闭合和冈瓦纳超大陆的最终组合相一致-
The Menderes Massif, exposed in the Western Anatolia, is tectonically overlain to the north by the Afyon Zone and to the south by the Lycian Nappes. In the northwest, two high-pressure units, the Cycladic Complex and overlying the Lycian Nappes, as well as the nappes of Izmir – Ankara Zone tectonically overlay the Menderes Massif. The metamorphic rock succession of the Massif can be divided into two main units: 1-Pan-African basement (core series) and 2-Palaeozoic – Early Tertiary metasedimentary rocks (cover series). * Dokuz Eylul University Faculty of Eng. Dept. of Geol. Eng. Tinaztepe Campus Muhendislik 35160 Buca / Izmir–Turkey (osman.candan@deu.edu.tr) ** Institut fur Erdund Umweltwissenschaften, Universitat Potsdam, Karl Liebknecht Str. 24, Potsdam 14476, Germany. ***Eberhard-Karls-Universitat Tubingen, Institut fur mineralogy, Petrologie und Geochemie, Lehrstuhl fur Geochemie, Wilhelmstrasse, 56, 72074 Tubingen ,Germany ****Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029-China ***** Died on 22nd of May in 2002, Faculty of Eng. Dept. of Geol. Eng. Tinaztepe Campus Muhendislik 35160 Buca / Izmir–Turkey translation by: Kerem AVCI The Pan-African basement shows a stratigraphy consisting of a partly migmatized metaclastic sequence and polymetamorphic basic and acidic igneous rocks that intruded into these metaclastics. This metaclastic sequence, which is composed of paragneiss and conformably overlying schist units reaches a minimum thickness of eight kilometers and forms the oldest rocks of the Pan-African basement of the Menderes Massif. Field studies and geochronological data suggest that the protoliths of the paragneisses are predominantly clastic sediments of litharenitic composition. Frequently, the paragneisses alternate and interfinger in all directions with micaschists and biotite-albite schists, originating from mudstone and subarkosic sandstone, respectively. The paragneisses are conformably overlain by a schist unit. The originally gradual sedimentary contact is represented by a paragneiss and schist intercalation. The schists are dominated by micaschists with biotite-albite schist layers, derived from mudstone and subarkose, respectively. In the Menderes Massif, the paragneisses are generally extensively migmatized. Widespread anatectic granites occur as irregular-shaped bodies with migmatized margins. The detrital zircons of the paragneisses yielded ages scattered between 610 – 2558 Ma. Detrital zircons of the schist unit of the Pan-African basement were dated at 592 – 3239 Ma. The intrusion ages of the orthogneiss showing clear intrusive contact relationship with metaclastic sequence range from 570 to 520 Ma. The granulite facies metamorphism of the paragneiss unit was dated at 583±5.7 Ma. These geochronological evidence and the contact relationships clearly reveal that the deposition age of the protoliths of the metaclastic sequence of the Pan-African basement can be constrained to Late Neoproterozoic between ca 590 – 580 Ma. The metaclastic sequence is intruded by large granitoid bodies and gabbroic stocks. The intrusion ages of the granitic precursors now represented by orthogneisses with changed mineralogical compositions and primary textures range from 520 to 570 Ma with a major event at about 550 Ma. These granites, which can be divided into three main groups (biotite orthogneiss, amphibole orthogneiss and tourmaline leucocratic orthogneiss) are the products of a poly-phase Pan-African acidic magmatic activity that intruded the metaclastic sequence. They are synto post-metamorphic intrusions with respect to the Pan-African orogeny. The basic meta-igneous rocks occurring in the Pan-African basement have gabbroic to noritic composition. They display massive cores and foliated margins that consist mainly of garnet amphibolites with relics of eclogites revealing the polymetamorphic history of the Pan-African basement. Field evidence and radiometric age data indicate that the primary contact relationship between the Pan-African basement and the Palaeozoic cover series in the Menderes Massif was an unconformity (Supra-Pan-African unconformity) and the cover series were sourced from the Pan-African basement. The protoliths of the paragneiss and schist of the Pan-African basement were deposited on the passive continental margin of a basin occurring between East and West Gondwana during the Late Neoproterozoic time (Mozambique ocean). All the magmatic and metamorphic ages obtained from Pan-African basement coincide with the closure of this ocean and the final assemblage of the Gondwana supercontinent during Late Neoproterozoic –