Dating of low-grade high-pressure Metamorphism in the Afyon Zone; W-Anatolia

在这笔赠款的第一个现场期间(2007-2008年)，确认了土耳其西南部以及整个阿费扬地区和东安纳托利亚的Bitlis地块的低品位高压岩石的范围和分布。这些发现表明，在构成中央安纳托利亚高原的kirşehir地块南部，持续存在一条主要的蓝片岩带。这些发现、其范围以及与北部的Tavsanli地区和南部的Taurid的关系显然要求在Kirsehir区块以南的Neotethys地区建立一个分支，这一事实受到许多土耳其同事的强烈质疑。在土耳其西部高压变质作用由北向南逐渐年轻的背景下，我们建议确定变质年龄，以约束Afyon高压带的折返历史。这包括Lycian推覆体和Menderes地块的部分盖层序列。阿费翁高压带以含镁铁石、蓝片岩相变泥岩为特征。我们在变质的河流-三角洲层序中发现了镁铁碳磷石作为造岩矿物。铁镁碳磷石只产于无钠长石岩石中，主要与多硅白云母伴生。因此，钠一定被完全淋溶了，而钾则留在了这些岩石中。因此，我们开始进行岩相和地球化学研究，以了解变质前的风化/蚀变和沉积条件，这些条件导致了容易形成镁铁石的岩石成分。这些调查将在这一赠款期间继续进行。

During the first field based period of this grant (2007-2008) extent and distribution of low-grade high-pressure rocks in SW Turkey and along the entire Afyon Zone and the Bitlis Massif in Eastern Anatolia was confirmed. The findings demonstrate the continuous existence of a major blueschist belt running south of the Kirşehir block, that forms the Central Anatolian plateau. These findings, their extent and the relation towards the Tavsanli zone in the north as well as the Taurids in the South clearly plead for a branch of the Neotethys south of the Kirsehir block, a fact that is highly contested by many Turkish colleagues. In the context of successively younger ages found in HP metamorphism of Western Turkey form North to South, we propose to determine the age of metamorphism for constraining the exhumation history of the Afyon HP belt. This includes the Lycian nappes and parts of the cover sequence of the Menderes Massif. The Afyon HP belt is characterized by Mg-Fe-carpholite bearing, blueschist facies metapelites. We found Mg-Fe-carpholite as rock forming mineral in a metamorphosed fluvio-deltaic sequence. Fe-Mg-carpholite occurs exclusively in albite free rocks, mostly associated with phengite. Thus, Na must have been leached completely, while K remained in these rocks. We therefore started performing lithofacies and geochemical investigations for understanding the pre-metamorphic weathering/alteration and sedimentation conditions which led to rock compositions prone to form Mg-Fe-carpholite. These investigations will continue during this grant period.