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

保加利亚和希腊的罗多普杂岩代表了一组变质逆冲推覆构造，记录了从侏罗纪到现在阿尔卑斯山造山变形的漫长历史，包括逆冲和伸展剪切与断裂时期。前人的工作表明，在阿尔卑斯山旋回(侏罗纪、白垩纪和第三纪)，曾发生过多次高压和超高压变质作用。我们的工作假设是，这些变质事件是微大陆多次碰撞的结果，高压和超高压岩石的折返是多大陆碰撞固有过程的结果。我们打算通过分析保加利亚和希腊西部罗多普杂岩(里拉、皮林、西罗多普斯)的构造和变质演化，结合野外填图、剪切带(构造、微构造和结构)的运动学分析、变质岩石学(P-T决定)和年代学(锆石的SHRIMP定年)，来研究这些事件的运动学、时间和板块构造背景。罗多普杂岩西部的研究区非常适合研究多大陆碰撞的影响，因为存在重要的挤压和伸展剪切带、蛇绿缝合带、构造前、同生和构造后的花岗岩侵入体，允许测定剪切带的年龄，以及第三纪与拆离有关的盆地，其位置和沉积物充填记录了伸展变形的后期阶段和变质杂岩的剥落。

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.