Separate Eocene–Early Oligocene and Miocene stages of extension and core complex formation in the Western Rhodopes, Mesta Basin, and Pirin Mountains (Bulgaria)

摘要: Abstract The Rhodope Metamorphic Province in Bulgaria and Northern Greece has been affected by significant extensional tectonics since the Middle to Late Eocene. An important fault system active Eocene Early Oligocene includes Ribnovo Fault on eastern side of Mesta Basin Vertiskos–Kerdilion Greece. Together with several minor normal relicts identified during this study, these represent an originally west-southwest-dipping, low-angle (at least at end faulting) greenschist-facies mylonites footwall cataclasites along plane, Mesta–Kerdilion Detachment, exposed over ca. 150 km strike about 50 km parallel slip direction. During intrusion plutons Pirin Mountains 32 Ma, was uplifted form a large anticline strike, offset antithetic, northeast-dipping faults northeastern flank (Dobrotino Breznitsa faults). Detachment later, Miocene, again crosscut southwest-dipping Strimon Valley which accommodated important, core complex-like exhumation South, strongly diminishing finally ceasing towards north. This rotational activity represents onset extension that led opening Aegean Basin. can be viewed as precursor this, but slightly different kinematics (i.e. not involving vertical-axis rotation) separated time from following events phase relative tectonic quiescence Oligocene.