Neven Georgiev

Sofia University "St. Kliment Ohridski" · Department of Geology and Paleontology

The Rhodope Metamorphic Complex in Bulgaria has been established as a Mesozoic ultra‐high‐pressure metamorphic province by findings of microdiamond in gneisses. Additionally, Variscan ultra‐high‐pressure metamorphism has been proposed for the Ograzhden/Vertiskos Unit in the Upper Allochthon of the Rhodope Metamorphic Complex, based on findings of c...

Following a tectonic scheme proposed by Janák et al. (2011; Journal of Metamorphic Geology 29, 317-332) and Pleuger et al. (2011; Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 162, 171-192), the Rhodopes are composed of four nappe complexes, from bottom to top the Lower, Middle, and Upper Allochthon and the Circum-Rhodope Belt. Rocks...

The Rhodope Metamorphic Complex is a nappe pile of four large allochthonous megaunits, referred to as Lower, Middle, Upper, and Uppermost allochthons. These were originally derived from different paleogeographic provinces and were stacked on top of each other in the course of convergent processes along the European continental margin between the La...

AMS Analysis of Tectonic Gauge

The Rhodopes in Bulgaria and Greece represent a nappe stack of high-grade units with polymetamorphic history. Constraining the time of metamorphism in individual subunits is essential for unraveling the controversial framework of subduction, exhumation and nappe stacking. Here we present new evidence for Late Cretaceous high-pressure metamorphism i...

Evidence for ultrahigh-pressure metamorphism (UHPM) in the Rhodope Metamorphic Complex comes from occurrence of diamond in pelitic gneisses, variably overprinted by granulite facies metamorphism, known from several areas of the Rhodopes. However, tectonic setting and timing of UHPM are not interpreted unanimously. Linking age to metamorphic stage i...

The Rhodope Metamorphic Complex is a stack of allochthons assembled during obduction, subduction, and collision processes from Jurassic to Paleogene and overprinted by extensional detachment faults since Middle Eocene. In the study area, the following nappes occur in superposition (from base to top): an orthogneiss-dominated unit (Unit I), garnet-b...

The metamorphosed thrust stack of the Rhodopes comprises a level with ophiolites (Middle Allochthon) under- and overlain by continent-derived allochthons. The Upper Allochthon represents the European margin but the origin of the Lower Allochthon remains controversial, with suggestions that it may be derived from an inferred microcontinent (Drama) o...

The Alpine nappe pile of the Rhodope Metamorphic Complex in Bulgaria and Greece was assembled during a protracted history of subduction and collision along the southern margin of Europe. It is subdivided into four thrust systems or tectonic superunits, the Lower, Middle, Upper and Uppermost Allochthon. Previous Lu-Hf dating (KIRCHENBAUR et al., 201...

The Ordovician Tschigot granodiorite, hosted by the Texel complex, underwent polyphase tectonometamorphic overprint during the Variscan and Alpine orogenies. The main magmatic body forms a large sigma-like clast. While the contact with the host rock is characterized by a strong and coherent mylonitic foliation the internal part of the body is almos...

Introduction The Late Alpine syn-to post collisional extension and attendant tectonic denudation in the inner parts of the Alpine Orogen on the Balkan Peninsula is a well-doc-umented fact. In contrast to the Central and Eastern Rhodopes, where the exhumation of the lowermost high grade units occurred in the Paleogene, the west-ern parts of the Rhod...

In the Central Rhodopes of southern Bulgaria, an eclogite-bearing rock sheet belonging to the Middle Allochthon (Starcevo Unit) is over- and underlain by eclogite-free, amphibolite-facies rock units along low-angle shear zones, the Borovica Shear Zone at the top and the Starcevo-Ardino Shear Zone at the base. The age of these shear zones is determi...

The Rhodope Mountains in Northern Greece and southern Bulgaria have traditionally been viewed as having a structural position internal of the Vardar suture, hence, above the highest nappes of the Hellenides. Accordingly, their last major orogenic event has been associated with microcontinent accretion to the European margin prior to the closure of...

The Nestos Shear Zone (NSZ) in the Rhodope Metamorphic Province is a major high-strain zone between two metamorphic terranes. Microdiamond-bearing ultrahigh-pressure (UHP) rocks occur in the NSZ which was therefore interpreted as a suture zone where subduction and exhumation of these rocks and terrain accretion occurred during the Mesozoic. Our pet...

The Central Rhodope crystalline basement in the eastern flank of the Central Rhodopean Dome (including the Arda 1, Starcevo, Borovica and Kardzali units in Bulgaria or Sidironero and Kimi units in Greece) is a pile of Alpine high-grade metamorphic units. The structurally lowest of these units (Arda 1 and Starcevo units) were migmatised in the Late...

A new occurrence of kyanite eclogite in the Pirin Mountains of southwestern Bulgaria within the rocks belonging to the Obidim Unit of the Rhodope Metamorphic Complex is presented. This eclogite provides important information about the peak–pressure conditions despite strong thermal overprint at low pressure. Textural relationships, phase equilibriu...

The Rhodope Metamorphic Province in the area around the Mesta Graben (SW Bulgaria) exposes a structurally lower complex, the Pangaion-Pirin Complex of Variscan continental crust and its cover (mostly orthogneiss and marble), and a higher complex, the Rhodope Terrane of mixed oceanic and continental origin with metamorphosed Jurassic arc magmatites....

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 in the Eocene and Early Oligocene includes the Ribnovo Fault on the eastern side of the Mesta Basin in Bulgaria and the Vertiskos–Kerdilion Fault in Greece. Togethe...

Integrating the results of recent structural geological fieldwork with age constraints reported in the literature we propose a kinematic model for Eocene to Miocene tectonics in the western Rhodopes. In the past years, several authors have claimed that low-angle normal faults in the western Rhodopes and adjacent external Hellenides formed in the fr...

In the area of Central Stara Planina Mountain and northernmost parts of Central Sredna Gora the pre-Mesozoic basement of Balkanides is largely exposed. Despite Alpine tectonic overprint the area provides unique chance to deciphering the Variscan history. Of greatest interest is the contact juxtaposing two contrastingly different units (terrains): i...

The Rhodope Metamorphic Province represents the core of an Alpine orogen affected by strong syn- and postorogenic extension. We report evidence for multiple phases of extensional unroofing from the western border of the Rila Mountains in the lower Rila valley, SW Bulgaria. The most prominent structure is the Rila-Pastra Normal Fault (RPNF), a major...

The basement of the Rhodopes in south Bulgaria and northeast Greece is built up mostly of thrust nappes and plutons that were emplaced during a protracted Alpine history. Subduction and accretion processes have lasted at least from the Late Jurassic until the Early Eocene, as evidenced by radiometric ages for the high- to ultrahigh-pressure metamor...

The Nestos Shearzone can be traced over 100 kilometers and separates the two main units of the Rhodopes, the Upper Complex in the hangingwall from the Pangaion-Pirin Unit in the footwall. The Upper Complex consists of mingled continental and oceanic basement rocks, intruded by granitic bodies of Cretaceous and Tertiary age. It underwent at least am...

The emplacement mode of Upper Cretaceous plutons from the southwestern part of the Sredna Gora Zone (Bulgaria): structural and AMS study Several plutons located in the southwestern part of the Sredna Gora Zone — Bulgaria are examples of the Apuseni-Banat-Timok-Sredna Gora type of granites emplaced during Late Cretaceous (86-75 Ma) times. The studie...

Metamorphic basement rocks of the Western Rhodope Complex in Bulgaria and Greece belong to a synmetamorphic nappe stack made of continental crust and ophiolites. This nappe stack has been assembled during a long and complex history from Jurassic times to the present. During late and post-collisional stages of the Alpine cycle, extension along low-a...

We present an E-W profile through the Western Rhodopes (Bulgaria). It runs through basement rocks, granitic intrusions therein and Tertiary extension-related structures such as the Strouma and the Mesta Graben. Two major alpine units are exposed in the basement, the Pangaion-Pirin complex below and a mixed gneiss unit above. The Pangaion-Pirin unit...

Precise U–Pb geochronology and Hf isotope tracing of zircon is combined with whole-rock geochemical and Sr and Nd isotope data in order to unravel processes affecting mafic to felsic calcalkaline magmas prior to and during their crystallization in crustal magma chambers along the southern border of Central Srednogorie tectonic zone in Bulgaria (SE...

Our data demonstrate strongly reworked basement-cover relations and the development of a complex tectonic zone in Tvardishka Stara Planina mountain. In the area of Lazovo river valley the metamorphic basement rocks were emplaced on Permian rocks, resulting in the formation of decametre-scale thrust imbricates. The deformation was associated with de...

This paper considers petrographic and mineralogical data from some plutonic bodies in Central Sredna Gora zone. Microtextural features of the rocks and analytic data obtained for Elshitsa-Boshulia pluton support the idea of magma mixing and mingling processes. From selected samples were calculated P-T values at different stages of crystallization o...

Deciphering the character and timing of nappe em- placement is of prime importance for tectonic syn- theses. Here we present new data on the thrust tec- tonics in Tetevenska Stara Planina (so-called Vezhen massif) that are leading to completely new tectonic model and evolutionary scheme. First data on the thrust tectonics for this area were present...

The structural, petrologic and magnetic (AMS) features of plutonic bodies, placed in Central Sredna Gora region, show an evidence of processes of mingling and mixing of two different compositional magmas - felsic and mafic. These two magma types have been generated at different continental lithosphere levels. The emplacement as well as a syn- and p...

The significance of the Anton shear zone is reassessed based on structural studies. It is a fairly narrow north-verging reverse/thrust zone along the southern contact of the Variscan Vejen pluton with low-grade metamorphic host rocks to the north of the village of Anton. Field data suggest that the deformation occurred after the pluton emplacement...