Structural studies in the nappes of Southeast Strandža

The present complex structure of SE Strandza is a result of two superimposed deformation event : Late Cimmerian (?) thrusting and Subhercynian (?) folding.
   Two main Late Cimmerian (?) regional tectonic unit are divided: autochthon (Paleozoic granite, Triassic and Lower-Middle Jurassic sediments of Subbalkanide type) and allochthon (Strandža type Triassic). The allochthon consists of two subunits. The lower nappe is made up of the dominantly carbon ate rock of Malko Tarnovo, Kondolovo and Lipačka Formations (Middle – Upper Triassic) and the upper – of various metasediments and rare metavolcanics of Gramatikovo, Zaberska, Strȃvnica and Stoilovo Formations (Lower - Middle Triassic, possibly Paleozoic).
   The metamorphic zoning is inverted: greenschist facies in the upper nappe and local, very low-grade metamorphism in the lower nappe and the autochthon.
   The Late Cimmerian (?) phases of fold deformation in the autochthon and the lower nappe are similar: D₁ – recumbent folds; D₂ – upright folds; D₃ – kink-bands. The upper nappe shows different pattern: D₁ – intrafolial folds; D₂ – recumbent fold; D₃ – upright and N vergent folds of variable morphology; D₄ – upright open folds; D₅ – kink-zones. The intrafolial folds D₁ in the upper nappe are synchronous to greenschist metamorphism which took prior to the formali on of nappes, in other SPT conditions. D₂, D₃ and D₅ in the upper nappe are correlated with D₁, D₂ and D₃ in the lower nappe and the autochthon. They are probably synchronous to the thrusting and the associated very low-grade metamorphism.