Tectonometamorphic evolution of the Western Rhodope complex - a record of multiple continent collision?

保加利亚和希腊的罗多彼杂岩代表了一组变质逆冲推覆体，记录了从侏罗纪到现在的阿尔卑斯造山变形的漫长历史，包括逆冲和伸展剪切和断裂的时期。以前的工作表明，高压和超高压变质作用发生在阿尔卑斯山旋回（侏罗纪，白垩纪和第三纪）的几个时间。我们的工作假设是，这些变质事件是由多个碰撞的微大陆，和折返的高压和超高压岩石的过程中固有的多个大陆碰撞。我们打算通过分析保加利亚和希腊的西罗多彼杂岩（里拉、皮林、西罗多彼）的结构和变质演化，结合野外测绘、剪切带运动学分析（结构、显微结构和纹理）、变质岩石学（P-T测定）和地质年代学（锆石U-Pb SHRIMP定年）来研究这些事件的运动学、时间和板块构造背景。罗多彼复合体西部的研究区非常适合研究多大陆碰撞的影响，因为存在重要的剪切带，包括压缩和拉伸剪切带，蛇绿岩缝合线，构造前、构造同和构造后花岗岩侵入体，可以确定剪切带的年代，以及第三纪、与伸展有关的盆地，其位置和沉积物充填记录了伸展变形的晚期阶段和变质杂岩的去顶。

The Rhodope Complex in Bulgaria and Greece represents a stack of metamorphic thrust nappes recording a long history of Alpine orogenic deformation from Jurassic to present, including periods of thrusting and of extensional shearing and faulting. Previous work suggested that high- and ultrahigh-pressure metamorphism occurred at several times during the Alpine cycle (Jurassic, Cretaceous, and Tertiary). Our working hypothesis is that these metamorphic events resulted from multiple collisions of microcontinents, and that the exhumation of the high- and ultrahigh-pressure rocks resulted from processes inherent in multiple continent collision. We intend to study the kinematics, timing, and plate tectonic setting of these events by analysing the structural and metamorphic evolution of the western Rhodope complex (Rila, Pirin, West Rhodopes) in Bulgaria and Greece, using a combination of field mapping, kinematic analysis of shear zones (structures, microstructures and textures), metamorphic petrology (P-T-determi nation), and geochronology (U-Pb SHRIMP dating of zircon). The study area in the western part of the Rhodope complex is ideally suited for investigating the effects of multiple continent collision because of the presence of important shear zones, both compressional and extensional, of ophiolitic sutures, of pre-, syn- and posttectonic granitoid intrusions allowing to date the shear zones, and of Tertiary, detachment-related basins whose position and sediment fill record the late stages of extensional deformation and the unroofing of the metamorphic complexes.