East Rhodope Research Articles

Ethnobotanical and Ethnopharmacological Study in the Bulgarian Mountain Rhodopes: Part II—Contemporary Use of Medicinal Plants

Rhodopes Mountain is ethnobotanically poorly studied, but our preliminary observation in a number of settlements revealed that even nowadays, the local population relies solely on previously collected medicinal plants. We aimed to assess the contemporary use of medicinal plants in the Central and East Rhodopes and the health conditions that local communities address with them. The ethnobotanical field data were collected through an in-depth method in combination with semi-structured face-to-face interviews, adapted with modifications to the objectives of this study. The following quantitative ethnobotanical indices were used in this study: informant consensus factor (ICF), fidelity level (FL), and Jaccard similarity coefficient or Jaccard index (JI). Data analyses from our field research showed that 92 informants mentioned the utilization of a total of 114 plant species. The results of this study reveal that in both regions of the Rhodopes, medicinal plants are mentioned most often in relation to diseases affecting nervous, respiratory, digestive, and cardiovascular systems, followed by reproductive, urinary, immune, and musculoskeletal. The risk of disruption or loss of traditional knowledge of medicinal plants is expected in the condition of cultural globalization. However, there is no metrified data about the use of medicinal plants in the Rhodopes from the past. The application of statistical indices in this research will make such assessment and monitoring possible in the future.

Late Permian high-pressure metamorphism in the Devesil Unit, East Rhodopes (SE Bulgaria) – Single or multiple metamorphic events

Metaeclogites from the Devesil Unit, East Rhodopes are studied. Well preserved eclogite paragenesis is presented by omphacite+garnet+rutile and is obliterated by still high temperature retrograde assemblage of newly formed garnet, diopside, amphibole, plagioclase, titanite, and quartz. The P-T conditions of the high pressure metamorphism are in the range 620–665 °C and 1.8–2.0 GPa, whereas the retrograde stage occurs at temperature 600–650 °C and pressure 0.6–0,8 GPa. Cathodoluminescence images and LA-ICP-MS dating of zircon grains point to multiple metamorphic origin of the mineral the earliest with Late Permian–Early Triassic age, followed by Early Jurassic and Early Cretaceous metamorphic events.

Ethnobotanical and Ethnopharmacological Study in the Bulgarian Rhodopes Mountains—Part _I

Traditional knowledge of medicinal plants and their uses has been well documented in Bulgaria in the past. However, we know little about the contemporary traditional application of medicinal plants. Rhodopes Mountain is an ethnobotanically poorly studied region. This region is suitable for conducting field research in ethnobotany for several reasons: (i) our preliminary observation in a number of settlements revealed that the local population, in particular, relies solely on previously collected medicinal plants in winter months even in modern times; (ii) due to the relative isolation of the area, considerable authenticity of traditional methods of medicinal plant use is retained there. The aim of this study is ethnopharmacological and ethnobotanical research among the population of the Rhodopes to evaluate the contemporary use of medicinal plants. The field ethnobotanical data were collected through the in-depth method in combination with a semi-structured face-to-face interviews, adapted with modifications to the objectives of this study. The quantitative ethnobotanical index Use Value (UV) was calculated. Here we suggested a new approach in ethnobotanical research. We used nomograms to present a large volume of medicinal plants’ application data, classified by the degree of their UV. This allows for a much broader view of collected and processed data. Data analyses from our filed research showed that the 92 informants mentioned utilization of a total of 114 plant species belonging to 52 families and 110 genera. The most common plants were from the families Asteraceae (16.7%), Lamiaceae (12.3%), Rosaceae (9.6%) and Amrillydaceae (3.5%), followed by Crassulaceae, Plantaginacea, Oleaceae and Solanaceae. The data presented in six nomograms revealed the most popular plants, the way of application and the corresponding medical indications in the Central and East Rhodopes, and the differences between the two sub-regions. Sempervivum tectorum, Tussilago farfara and Plantago major are the most often reported plants in the Central Rhodopes while these are Cotinus coggygria, Prunus spinosa and Teucrium polium in the East Rhodopes. The results of the study show that in the Rhodopes, the contemporary application of traditional medicinal plants is pretty much vivid. The locals in the Rhodopes still use the traditional knowledge and rely on plants to treat various health problems. They use common plants in a sustainable manner and are open to the cultivation of Sideritis scardica—a species which became rare after overexploitation.

GEOCHEMISTRY AND TECTONIC SETTING OF ECLOGITE PROTOLITHS FROM KECHROS COMPLEX IN EAST RHODOPE (N.E. GREECE)

Eclogites and partially amphibolitized eclogites from the metamorphic Kechros complex in East Rhodope are studied in order to provide the geodynamic framework for the origin of their protoliths. Geochemical evidence from whole rock major and trace element concentrations shows two distinct protolith groups. The low-Fe-Ti eclogites (Charakoma locality) have low-TiO2 content (<0.67 wt%), negative Nb anomalies, positive Sr anomalies, small negative Zr and Hf anomalies and variable enrichments in LILE (e.g. Rb and Ba). The REE patterns are characterized by strong LREE enrichment (LaN/YbN=5.45-5.81), HREE depletion (GdN/YbN=1.60-1.63) and HREE abundance within the rangeof 9-10 × chondrite. The high-Fe-Ti eclogites (Kovalo and Virsini locality) have variable Sr contents, small to moderate LILE enrichment, HREE`s similar to MORB values and absence of Nb anomalies. The REE patterns of the Kovalo and Virsini eclogites are characterized by LREE depletion and relative flat MREE HREE patterns at approximately 20-30 × chondrite concentrations. Our results suggest that the protoliths of the Low-Ti eclogites show a continental rifting tectonic environment. In contrast, the protoliths of the High-Ti eclogites indicate formation of their protoliths by partial melting in an extensional oceanic environment.

Ancient Gold Mining at Ada Tepe, East Rhodopes, Bulgaria. Mineralogical Features of Au-Containing Fe-Oxides/Hydroxides from the Ada Tepe Gold Deposit. Their Significance in Clarifying the Ancient Gold Mining

Ada Tepe is the oldest known open-pit mine on the Balkan Peninsula for mining gold from host rocks. The mine probably started operation around 1500 BC and continued to function until the end of the 12th to the middle of the 11th century BC. The sedimentary and hydrothermally altered host rocks in the upper zone of Ada Tepe are usually of a grey or yellow colour or, in some places, yellow-brown. The rock pieces in the waste dumps are usually darker, with a red or red-brown coloration, which is obviously not connected to geological processes. It is suggested that the difference in colour between the host rocks and the fragments in the waste dumps are due to the phase transformation of minerals caused by the ancient miners using fire to fracture the host rocks in order to extract the gold ore. The majority of the analysed rock samples have a polyphase composition of goethite, hematite, schwertmannite, Au-Ag alloys, iron ochres, quartz and adularia. The phase diagnostics were performed by ore microscopy and powder X-ray diffraction (PXRD), morphological peculiarities were determined by scanning electron microscopy (SEM) while the thermal behaviour was investigated by differential thermal analysis and thermo gravimetric (DTA-TG) method. This paper will present the analytical results, which led to the conclusion that the difference in the coloration is due to the processes of transformation of nano-sized Fe3+ (oxy)hydroxides and (oxy)hydroxysulfate minerals caused by anthropogenic thermal processing.

The Main Characteristic Features of the Bulgarian Orlitza Dialect (From the East Rhodopes)

This article describes the main characteristic features of the dialect spoken by Muslim Bulgarians inhabiting the East Rhodopian Bulgarian village of Orlitza. The dialect features phonetic changes © ∆ a, u ∆ a, ќ ∆ ’a, u ∆ ’a; the traces from the Old Bulgarian nasal vowels; the use of a definite article from the Old Bulgarian demonstrative pronoun ou “this” unlike most of the other Rhodopian dialects where a triple article derived from the demonstrative pronouns ou, nu, iiu is in use; as well as interesting lexemes, often from Turkish origin. Кeywords: Bulgarian language, Bulgarian dialectology, East Rhodopes

The metamorphic evolution of the high-pressure Kechros complex in East Rhodope (NE Greece): Implications from Na–Al-rich leucocratic rocks within antigorite serpentinites

The Rhodope Domain in NE Greece is comprised of different tectonometamorphic complexes involved in the Alpine collisional history between the Eurasian and African plates. The Kechros Complex represents the lowermost tectonic unit in East Rhodope, and contains a metamorphic suite of Na–Al-rich leucocratic rocks (i.e., alkali feldspar granites, alkali syenites and syenites) within the Virsini antigorite serpentinite.Based on the calculated P–T pseudosection and superimposed isopleths for a meta-syenite, we have determined a peak pressure and temperature of 1.55±0.03GPa and 550±25°C, suggesting HP metamorphism for leucocratic rocks enclosed in the Virsini serpentinized peridotites. The retrograde conditions suggest a prolonged exhumation history, with equilibration conditions first at P 1.1±0.03GPa and T 580±20°C and then at P 0.55±0.04GPa and T 430±30°C. The P–T conditions suggest an early rapid uplift event followed by a late-stage exhumation period, characterized by rapid cooling at relatively isobaric conditions. Similar metamorphic signatures are also recorded in continental rocks of the Kechros complex (i.e., orthogneisses, metapelites), suggesting that crustal and mantle rocks underwent a common Alpine tectonometamorphic evolution.The exact ages of HP metamorphism in the Kechros Complex are not well constrained, however, a Rb–Sr age of 37Ma from a neighboring orthogneiss records a stage of exhumation that may be contemporaneous with the Eocene HP metamorphism (49–55Ma; i.e., recorded in the Nestos Shear Zone of Central Rhodope). We interpret this to be the result of the eventual closure of the Axios/Vardar Ocean and subsequent subduction of the Apulian continental crust (a promontory of the Africa continent) under the southern margin of the European continent in the late Cretaceous and early Tertiary.

The “Bulgarian Mohammedans” (Pomaks) in the East and Central Rhodopes: the problem of identity

The “Bulgarian Mohammedans” (Pomaks) in the East and Central Rhodopes: the problem of identity

Pressure–temperature evolution of eclogites from the Kechros complex in the Eastern Rhodope (NE Greece)

The Rhodope Domain in NE Greece consists of different tectonometamorphic complexes involved in the Alpine collisional history between the Eurasian and African plates. In the Kechros Complex, which is the lowermost tectonic unit in the East Rhodope, a lense of kyanite eclogite occurs within orthogneiss and common eclogites are found between serpentinized peridotite and underlying pelitic gneisses. In kyanite eclogite, the high-pressure (HP) mineral assemblage is Grt + Omp (Jd35–55) + Ky + Ph + Qz + Rt + (indirectly inferred Tlc + Law); a Na-rich tremolite and zoisite formed at or near peak metamorphic conditions. In common eclogites, the HP mineral assemblage is Grt + Omp (Jd29–41) + Rt and, with less certainty, Amp (Gln-rich + Brs + Wnc + Hbl) ± Czo. The inclusions in garnet are glaucophane, actinolite, barroisite, hornblende, omphacite, clinozoisite, titanite, rutile and rarely paragonite and albite. In kyanite eclogite, peak P–T conditions are constrained at 2.2 GPa and 615°C using garnet–omphacite–phengite geothermobarometry and very similar values of 585 ± 32°C and 2.17 ± 0.11 GPa with the average P–T method, by which conditions of formation could also be narrowed down for the common eclogite (619 ± 53°C and 1.69 ± 0.17 GPa) and for a retrogressed eclogite (534 ± 36°C and 0.77 ± 0.11 GPa). Ages for the HP metamorphism in the Kechros Complex are not yet available. A Rb–Sr white mica age of 37 Ma from orthogneiss records a stage of the exhumation. The HP event may be coeval with the Eocene HP metamorphism (49–55 Ma) recorded in the Nestos Shear Zone in Central Rhodope and in the Attic-Cycladic crystalline belt, where it is interpreted as the result of subduction and final closure of the Axios/Vardar ocean and subsequent subduction of the Apulian continental crust (a promontory of the Africa continent) under the southern margin of the European continent in the late Cretaceous and early Tertiary.

Structural state of microcrystalline opals: A Raman spectroscopic study

The structure of natural hydrous silica is complex and its study requires the complementary application of several methods. To elucidate the structural state of opaline silica of different geneses, microcrystalline opals from siliceous rocks, geodes, and bentonite clays from East Rhodopes, Bulgaria, were analyzed by Raman spectroscopy, X-ray powder diffraction, electron microscopy, and thermogravimetric and differential thermal analysis. Comparison of X-ray diffraction and spectroscopic data for a series of microcrystalline opals showed that the fraction of tridymite-like structural units can be estimated using the relative intensity of the Raman scattering near 350 cm-1. Opals displaying an intense, poorly resolved Raman band centered near 330.360 cm-1 contain a larger proportion of nanosized spatial regions with tridymite-type atomic arrangements as opposed to cristobalite-type arrangements. The results demonstrate the ability of Raman spectroscopy to characterize the finescale structure of opal and to better distinguish opals showing similar XRD patterns. The application of Raman micro-spectroscopy showed that on intermediate-range scale the atomic structure of opal lepispheres is closer to the framework topology of tridymite than to that of cristobalite

Geochemistry of amphibolitized eclogites and cross-cutting tonalitic–trondhjemitic dykes in the Metamorphic Kimi Complex in East Rhodope (N.E. Greece): implications for partial melting at the base of a thickened crust

In the ultra-high pressure Metamorphic Kimi Complex widespread tonalitic–trondhjemitic dykes, with an intrusion age ca. 65–63 Ma, cross-cut boudins and layers of amphibolitized eclogites. Geochemical investigation proclaims the tied genetic relationship of the amphibolitized eclogites and the associated tonalitic–trondhjemitic dykes. The major and trace element contents and rare earth element patterns of the amphibolitized eclogites indicate formation of their protoliths by fractional crystallization of tholeiitic magmas in a back-arc environment. The tonalites and trondhjemites are characterized by moderate to high Sr contents (>130 ppm), and low Y (<8.2 ppm) and heavy rare earth element contents (Yb content of 0.19–0.88 ppm). The chemical composition of the tonalitic and trondhjemitic dykes are best explained by partial melting of a tholeiitic source like the amphibolitized eclogites with residual garnet and amphibole, at the base of a thickened crust during Early Tertiary subduction/accretion at the southern margins of the European continent.

Dolomitic marbles from the ultrahigh-pressure metamorphic Kimi complex in Rhodope, N.E. Greece

Summary Dolomitic marbles from the Organi and Pandrosos areas of the ultrahigh-pressure (UHP) metamorphic Kimi complex in East Rhodope, N.E. Greece have the mineral as- semblage: Cal þ Dol þ Ol þ PhlDiHblSplTi-Chu þ retrograde Srp and Chl. Several generations of calcite and dolomite with variable composition and texture represent different stages of the P-T evolution: The first stage is represented by matrix dolomite (XMgCO3 ¼ 0.48) and relic domains of homogenous composition in matrix calcite (XMgCO3 ¼ 0.11-0.13); the second stage is evident from precipitation of lath- shaped and vermicular dolomite in matrix calcite. The third stage is represented by veinlets of almost pure CaCO3 and domainal replacement of prior calcite by nearly pure CaCO3 þ Ca-rich dolomite (XMgCO3 ¼ 0.34-0.43). Matrix dolomite adjacent to CaCO3 veinlets also becomes Ca-rich (XMgCO3 ¼ 0.42). In fact, Ca-rich dolomites with XMgCO3 in the range of 0.40-0.34 are reported for the first time from metamorphic marbles. Coexisting Ca-rich dolomite and Mg-poor calcite cannot be explained by the calcite- dolomite miscibility gap. This assemblage rather suggests that Mg-poor calcite was aragonite originally, which formed together with Ca-rich dolomite according to the reaction Mg-Cal ! Arg þ Dol (1) at ultrahigh pressures and temperatures above at least 850 � C, when dolomite becomes disordered and incorporates more Ca than coex- isting aragonite does in terms of Mg. The simplest explanation of these observations probably is to suggest two metamorphic events: The first one represented by relic matrix carbonates at relatively low to mod- erate pressures and temperatures of ca. 750 � C, and the second one limited by the mini- mum temperatures for dolomite disorder (ca. 850 � C) and in the aragonite þ dolomite

Identification of repeated Alpine (ultra) high-pressure metamorphic events by U–Pb SHRIMP geochronology and REE geochemistry of zircon: the Rhodope zone of Northern Greece

U–Pb sensitive high resolution ion microprobe (SHRIMP) zircon geochronology, combined with REE geochemistry, has been applied in order to gain insight into the complex polymetamorphic history of the (ultra) high pressure [(U)HP] zone of Rhodope. Dating included a paragneiss of Central Rhodope, for which (U)HP conditions have been suggested, an amphibolitized eclogite, as well as a leucosome from a migmatized orthogneiss at the immediate contact to the amphibolitized eclogite, West Rhodope. The youngest detrital zircon cores of the paragneiss yielded ca. 560 Ma. This date indicates a maximum age for sedimentation in this part of Central Rhodope. The concentration of detrital core ages of the paragneiss between 670–560 Ma and around 2 Ga is consistent with a Gondwana provenance of the eroded rocks in this area of Central Rhodope. Metamorphic zircon rims of the same paragneiss yielded a lower intercept 206Pb/238U age of 148.8±2.2 Ma. Variable post-148.8 Ma Pb-loss in the outermost zircon rims of the paragneiss, in combination with previous K–Ar and SHRIMP-data, suggest that this rock of Central Rhodope underwent an additional Upper Eocene (ca. 40 Ma) metamorphic/fluid event. In West Rhodope, the co-magmatic zircon cores of the amphibolitized eclogite yielded a lower intercept 206Pb/238U age of 245.6±3.9 Ma, which is interpreted as the time of crystallization of the gabbroic protolith. The metamorphic zircon rims of the same rock gave a lower intercept 206Pb/238U age of 51.0±1.0 Ma. REE data on the metamorphic rims of the zircons from both the paragneiss of Central Rhodope and the amphibolitized eclogite of West Rhodope show no Eu anomaly in the chondrite-normalized patterns, indicating that they formed at least under HP conditions. Flat or nearly flat HREE profiles of the same zircons are consistent with the growth of garnet at the time of zircon formation. Low Nb and Ta contents of the zircon rims in the amphibolitized eclogite indicate concurrent growth of rutile. Based on the REE characteristics, the 148.8±2.2 Ma age of the garnet–kyanite paragneiss, Central Rhodope and the 51.0±1.0 Ma age of the amphibolitized eclogite, West Rhodope are interpreted to reflect the time close to the (U)HP and HP metamorphic peaks, respectively, with a good approximation. The magmatic zircon cores of the leucosome in the migmatized orthogneiss, West Rhodope, gave a lower intercept 206Pb/238U age of 294.3±2.4 Ma for the crystallization of the granitoid protolith of the orthogneiss. Two oscillatory zircon rims around the Hercynian cores, yielded ages of 39.7±1.2 and 38.1±0.8 Ma (2σ errors), which are interpreted as the time of leucosome formation during migmatization. The zircons in the leucosome do not show the 51 Ma old HP metamorphism identified in the neighboring amphibolitized eclogite, possibly because the two rock types were brought together tectonically after 51 Ma. If one takes into account the two previously determined ages of ca. 73 Ma for (U)HP metamorphism in East Rhodope, as well as the ca. 42 Ma for HP metamorphism in Thermes area, Central Rhodope, four distinct events of (U)HP metamorphism throughout Alpine times can be distinguished: 149, 73, 51 and 42 Ma. Thus, it is envisaged that the Rhodope consists of different terranes, which resulted from multiple Alpine subductions and collisions of micro-continents, rather similar to the presently accepted picture in the Central and Western Alps. It is likely that these microcontinents were rifted off from thinned continental margins of Gondwana, between the African and the European plates before the onset of Alpine convergence.

ISLAND ARC ORIGIN OF THE VARIEGATED FORMATIONS FROM THE EAST RHODOPE, BULGARIA - IMPLICATIONS FOR THE EVOLUTION OF THE RHODOPE MASSIF

The Variegated Formations (VF) of the eastern Rhodope Mountains (SE Bulgaria) form part of the pre-Alpine basement of the region. They are composed of alternating sediments and igneous rocks with a high-grade metamorphic overprint. Numerous ophiolitic slivers are associated with the VF and include metamorphosed peridotites, ultramafic cumulates, and amphibolitized eclogites. The dismembered ophiolites usually form the base of the VF successions. The metasedimentary rock types contain terrigenous materials (metapsammites and quartzites) that frequently alternate with metapelites and marbles. The nature of this sedimentary package, along with the field relations and sedimentary features, reflects its flysch character. The metaigneous rocks of the VF occur either as layers interbedded with the metasediments, or as intrusive bodies that intersect the ultramafic rocks. The principal mineral phases in the metabasites are amphibole + plagioclase + quartz + epidote ± garnet ± chlorite. We calculate temperatures of 630°C to 520°C at 6-2 kbar pressures, indicating moderate amphibolite facies metamorphism. Major rock-forming minerals (amphibole, plagioclase, and garnet) exhibit zoning typical of retrograde P-T conditions. When plotted on tectonic-setting discrimination diagrams, the metabasic rocks of the VF fall mainly in the fields of modern boninites and arc tholeiites. They show low Ti and Zr contents and key elemental ratios of CaO/TiO2, Al2O3/TiO2, Ti/Zr, Ti/Y and Zr/Y, all transitional between island arc tholeiites and boninites. Chondrite-normalized REE patterns reveal the existence of two different trends: U-shaped REE patterns (for the majority of samples) and LREE depleted patterns. Regardless of the existence of these two trends, the [La/Sm]N ratios of the metabasites perfectly coincide with the same ratios for many Cenozoic boninite series. The flysch character of the sedimentary sequences, as well as the clear supra-subduction zone affinities of the igneous rocks, indicates that the VF formed in an oceanic island-arc setting. The boninitic affinities of the meta-igneous rocks indicate possible origin in an immature arc. The character of the VF and its association with the dismembered ophiolite slivers shows the presence of a suture zone. The East Rhodope suture zone distinguishes the VF from the rocks structurally below it, which consist of orthogneisses typical of continental crust. Existing U-Pb zircon data indicate that the orthogneisses are of Variscan age. New U-Pb zircon age data for the VF suggest Late Neoproterozoic ages for some protoliths. Based on regional correlations, the interpretation of the VF as a fossil accretionary prism can be useful for elucidating the structure of the whole Rhodope composite terrane, and for tracing the suture itself to the Central and Western parts of the Massif.

Distribution of the silver in Bulgaria ore deposits

The content of silver in the different, in terms of genesis and macrochemism, endogenic mineralisations in Bulgaria varies from 1-2 to 200 g/t, most frequently 5-35 g/t. The highest concentrations of this element are registered in the West Balkan region (lead-silver ores near Chiprovtsi, gold-sulphide ores near Govezhda and polymetallic ores Iskar-Vratsa ore region as well as Kremikovtsi deposit); in the Central Rhodopes region (lead-zinc deposits in Laki, Madan and Davidkovo ore fields, Ardino silver-polymetallic deposit); in the lead-zinc ores in Ossogovo ore region; in the East Rhodopes ore region (gold-silver-polymetallic ores in Madzharovo ore field and Popsko, silver-gold ores in Sedefche and Sarnak); in the East Srednogorie (gold-copper-polymetallic ores near Bakadzhik and Zidarovo). Some of the more significant favourable geological prerequisites for the accumulation of silver in the ores are: Late Paleozoic or Tertiary (Oligocene-Miocene) age, geodynamic environments of collision and zones with thick earth crust, anticlinoria and big horst-like uplifts, WNW and NW host structures, close to the surface or flange sections of the mineralisations. The mineralisations with higher content of silver are, as a rule, related to granites. Their host rocks are carbonates with development of metasomatic processes such as dolomitisation and granitoids with periore alterations of the quartz-sericite, quartz-mica (beresite), adular-sericite or quartz-adularia metasomatites and argillizites. The composition of the ores includes lithophile-chalcophile geochemical associations with prevalence of antimony. A favourable factor for the accumulation of silver is the lead-zinc macrochemism with prevalence of lead in zones with thick earth crust and the polymetallic - in zones with basificated (subocean type) earth crust. The mineral composition of the ores includes galena, sulphosalt silver minerals, the especially high silver-bearing tetrahedrite-tennantite series with prevalence of tetrahedrite and participation of magnesium and iron carbonates (siderite, ankerite, dolomite). The character of the silver-bearing mineralisations in Bulgaria is medium to low-temperature and, according to their peculiarities, they can be related to the mesothermal, epithermal or telethermal genetic classes.

U–Pb SHRIMP-dating of zircon domains from UHP garnet-rich mafic rocks and late pegmatoids in the Rhodope zone (N Greece); evidence for Early Cretaceous crystallization and Late Cretaceous metamorphism

U–Pb ion microprobe (SHRIMP) dating of zircon domains assisted by cathodoluminescence imaging was carried out on (1) a garnet-rich mafic rock and (2) a cross-cutting pegmatoid from the area of Kimi, East Rhodope. Quartz exsolution lamellae in cpx of the garnet-rich mafic rock point to a precursor supersilicic cpx implying pressures >2.5 GPa. This indicates UHP conditions for the studied geotectonic unit and is in line with the (rare) presence of radial cracks around quartz inclusions in garnet, which suggest the former presence of coesite. Bleb-shaped cpx inclusions in garnet may be interpreted as primary inclusions during garnet growth. However, based on their shape and general orientation, the possibility that they represent exsolutions from a precursor majoritic garnet, in an advanced state of recrystallization (coalescing initial needles) remains open and needs further investigation. If the latter is proven true, it implies minimum pressures of 4 GPa. The oscillatory zoned domains of the zircon crystals from the garnet-rich mafic rock yield a weighted mean age at 117.4±1.9 Ma (Early Cretaceous) for the magmatic crystallization of the protolith. The zircon domains characterized by clearly fainted oscillatory zoning and/or U-rich embayments of the same zircon crystals are interpreted as metamorphic domains. They yield a weighted mean age of metamorphism at 73.5±3.4 Ma (Late Cretaceous). Different degrees of Pb loss resulted in discordant ages scattering between the magmatic and metamorphic age. The euhedral oscillatory zoned zircons of the cross-cutting pegmatoid yield a weighted mean age of 61.9±1.9 Ma for the time of emplacement and crystallization of retrograde metamorphic fluids into the middle-upper crust. Two scenarios are considered as possible for the interpretation of the SHRIMP-results and the petrological observations: (1) the protolith was an ultra high pressure melt (probably a grt±cpx cumulate) crystallizing in the mantle at Early Cretaceous times, partly exhumed into the lithosphere by mantle upwelling, and then transferred to a subduction zone and metamorphosed under eclogite-facies conditions in the Late Cretaceous; (2) the protolith was a cumulate within a gabbroic melt crystallizing at high crustal levels in the Early Cretaceous and subsequently metamorphosed under UHP conditions in the Late Cretaceous. Retrograde stages of metamorphism (ca. 500 °C, 0.5 GPa) occurred at 61.9±1.9 Ma.The petrological findings, which provide evidence for UHP conditions for these rocks of the Kimi Unit, combined with the SHRIMP-results, reveal different conditions of rock formation at different times for the Rhodope zone. The existence of a subduction zone in the Late Cretaceous shows that the Rhodope was not metamorphosed as a single geotectonic element but consists of different terranes subducted and exhumed at different times.

Late Alpine (Palaeogene) superimposed depressions in parts of Southeast Bulgaria

The Late Alpine superimposed depressions in thе south-eastern part of the Balkan peninsula are structures of collisional-collapse type. They play a role of neoautochton which overlays a highly disintegrated Middle and Late Alpine orogen of collage-accretional character. It is represented by the Sredna Gora and Rhodope superunits. The superimposed depressions are of Palaeogene-Neogene age and are elements of a separate tectonic entity (Maritsa superimposed graben system) within the boundaries of the Balkanides-Anatolian segment of the Alpine mobile belt. The following three wide depressions on South Bulgarian territory are characterized in this paper: Upper Thrace Depression (UTD), East Rhodope Depression (ERD) and the East Thrace Depression (ETD). The Tertiary evolution of each depression is characterised by three up to five destructive stages. The Late Eocene and Oligocene stages are accompanied by an active polycyclic or monophase magmatism mostly represented by intermediate to acid volcanics. Ca-alkaline, subalkaline and alkaline magmas are distinguished. Basic volcanics of toleiitic, subalkaline to alkaline composition are rare. During the stages outlined, phenomena of compression or extension with exhumation are recorded. A number of important faults and fault zones formed during those stages, some of them being now represented by dike bundles. Essential overthrustings took place only along some faults of late Laramian and Savian age.

The basement-cover relations: some examples from the Sakar unit and the East Rhodopes

The basement-cover relations: some examples from the Sakar unit and the East Rhodopes

New fossil evidence for the Lower Paleogene (Krumovgrad Group) in the East Rhodope Mountains, SE Bulgaria

Аn Algal detritus which is the basic rock-forming material is established in the organogeneous limestones among the coarse-terrigenous deposits of the Кrumovgrad Group of the Mandritsa depression to the South of Ivaylovgrad along the Kostilkovska river valley. А various foraminiferаl assemblage is found in these rocks consisting mainly of the representatives of the families of Lagenidae, Discorbidae, Miliolidae, Textulariidae, Rotaliidae, Acervulinidae, Linderinidae. These bioassociations аrе typical of the reef (marine shallow-depth) facies. They contain most of the bioelements of the co-assemblages of the intraplatfоrm facies of the Paleocene and the Early uр to Middle Еосеnе basins of the South Tethys. Furthermore, they аrе analogous to the assemblages described in the Upper Раleocene of the West Carpathians and the Middle and Upреr Paleocene in the Dinarides. Following these соmраrisons, the age of the coarse-clastic deposits along the Коstilkovo river valley could bе referred to the span Upper Paleocene - Middle Еосеnе. Thus, the presence of marine Lower Paleogene sediments is proven also in the West part of the East Thracian depression.

Preliminary data on the K-Ar dating of the basic rocks from the region southerly of Momchilgrad, Eastern Rhodopes, Bulgaria

Volcanic rocks from the Eastern Rhodopes depression near to Bulgarian-Greek border are investigated. Six samples of basic altered rocks from 4 dykes and 2 larger bodies located into Kapinovo graben and Kushla volcano-tectonic structure are characterized. The K-Ar age of the basic dykes and small bodies is (31-32.5)±1.3 Ma and they are referred to the Early Oligocene (Rupelian). The time-span of the formation of the dykes corresponds as a whole to the time-span of the paroxismal volcanic events in the East Rhodope Volcanic Area.