Raya Raicheva

• PhD
• Professor (Assistant) at Bulgarian Academy of Sciences

Numerous Priabonian and Oligocene tuff layers within the Eastern and Central Europe Paratethys and Tethyan sedimentary basins attest for extensive volcanic activity during that period. However, the sources of these eruptions are completely unknown. Using precise radioisotopic dating, along with their stratigraphic relationships, we correlate some o...

The Oligocene Krumovgrad alkaline basalts and lamprophyre (KABL) intruded into the Kesebir-Kardamos and Byala Reka metamorphic domes carry various mantle and crustal xenoliths. This study presents the results from petrological and geochronological investigations of one granitic xenolith entrained in an alkaline (camptonite) dyke intruded into the B...

Numerous Eocene and Oligocene volcanic tuff layers within the Eastern, Central and Southern Europe sedimentary basins attest to extensive volcanic activity. Tephra dispersal of these tuffs covers areas of more than 1 000 000 km2, and the volume of erupted material to 1000s of cubic kilometers. The sources of the eruptions, however, remain unknown....

Volcanism during the Priabonian–Oligocene times (35–27 Ma) in the Rhodope Massif produced large volume of shoshonitic and calcalkaline lavas and three large volume silicic ignimbrites and fallout deposits. The youngest of these ignimbrites, named here as Perelik ignimbrite (PI), consists of three areas, previously described as three separate ignimb...

The Elatsite–Chelopech ore field in the northern part of the Panagyurishte district in Central Bulgaria comprises numerous spatially associated porphyry copper and epithermal gold deposits and prospects. In addition to the mineralization and alteration features, trace elements, lead and sulfur isotope signatures of sulfide minerals from porphyry co...

Clastic units unconformably overlie the metamorphic basement of the northern and western parts of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria, with suspected late Paleozoic-early Mesozoic depositional ages. In this article we present new geochemical data and U-Pb detrital zircon geochronology for ten samples from these clastic units. The...

Generally all orogenic ultra-potassic (U-K) rocks are formed after melting of metasomatised sub-continental lithospheric mantle via subducted crustal mica-bearing lithologies. Here we present another possible model, based on the study of the small Stomanovo U-K monzonite porphyry intrusion in the Central Rhodope Massif, Bulgaria. The monzonite...

A prominent subduction-related magmatic arc hosting significant mineralization formed in SE Europe during the Late Cretaceous. Previous studies on major magmatic centers and ore deposits suggested that this belt formed through southwards retreat of a subducting Neotethys oceanic slab. However, the timing and the petrologic characteristics of magmat...

A prominent subduction-related magmatic arc hosting significant mineralization formed in SE Europe during the Late Cretaceous. Previous studies on major magmatic centers and ore deposits suggested that this belt formed through southwards retreat of a subducting Neotethys oceanic slab. However, the timing and the petrologic characteristics of magmat...

Late Palaeozoic granitoids, meta-granitoids and meta-volcanic rocks predominate in the metamorphic basement of the northern and western parts of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria, together with the subsidiary Triassic meta-granitoids and meta-volcanic rocks. Generally, igneous minerals and textures are preserved, except in the...

This paper provides U–Pb zircon ages for a tuff bed in Eocene-Oligocene volcano-sedimentary sequence (Fissini-Sardes unit) on the Greek island of Lemnos. The obtained results of 33.3 Ma fall within the range of the precise 40Ar/39Ar age determination of erupted material from the Eastern Rhodope First Acid Volcanism (FAV), referred to as the Dazhdov...

Zircon obtained from a tuff layer from the Eocene-Oligocene volcanosedimentary sequence (Fissini-Sardes unit) in the Greek Island of Lemnos was dated using U-Pb technique. The results received indicate that the age of the layer is synchronous with one of the largest volcanic eruptions which occurred in the Eastern Rhodopes (SE Bulgaria). Previously...

We provide precise 40Ar/39Ar and U-Pb age dat from sanidine and zircon, respectively for the first Lower Oligocene supereruption in Europe, sourced in the Borovitsa volcano in the Eastern Rhodopes, Bulgaria

We focused on the Pirin–Pangeon–Thasos carbonate sequence of the Rhodope thrust system, combining Sr isotopes from marble with U–Pb dating of detrital zircons from interlayered schists with outcrop near the villages of Ilindentsi and Petrovo in Bulgaria. The youngest zircon age at Ilindentsi is 266 Ma, i.e. Middle Permian, while the youngest zircon...

New depositional age of the marble strata of the Circum-Rhodope Belt in Bulgaria

The Topolovgrad Group represents the Sakar-type Triassic in SE Bulgaria, which unconformably overlies the high-grade metamorphic basement, and consists of meta-sedimentary rocks subdivided into three formations (Chatalov, 1988). The lower clastic Paleokastro Formation passes gradually into the overlying clastic-carbonate Ustrem Formation, the upper...

This short communication reports a 251.4 ± 6.8 Ma age of a Permo-Triassic metagranitoid (augen gneiss) in the Bulgarian part of the Eastern Rhodopes. The rock is intruded by the early Eocene Drangovo pluton and represents part of the upper metamorphic unit of the Kessebir dome. The analyzed sample has slightly peraluminous (ASI = 1.11) granitic com...

Poster of EGU 2019 paper

17 Paleozoic granitoids and meta-granitoids dominate the metamorphic basement of the Sakar unit of the 18 Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria. In this article we present new whole-rock 19 geochemical data and U-Pb zircon geochronology for the Sakar unit granitoids. The igneous minerals and 20 textures are preserved, except the meta-g...

Abstract combines U-Pb detrital zircon geochronology and Sr isotopes in Permian-Triassic units in Bulgaria.

Palaeozoic granitoids and meta-granitoids dominate the metamorphic basement of the Sakar unit of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria. In this article, we present new whole-rock geochemical data and U–Pb zircon geochronology for the Sakar unit granitoids. The igneous minerals and textures are preserved, except the meta-granitoids...

Detrital zircon and Sr isotope constraints on the deposition of the Pirin-Pangeon carbonate platform, Lower Rhodope Thrust System, Pirin unit, Bulgaria Nikolay Bonev (1), Petyo Filipov (2), Raya Raicheva (2), Massimo Chiaradia (3), Robert Moritz (3) (1) Department of Geology, Paleontology and Fossil Fuels, Sofia University St Kliment Ohridski, S...

Fig. 1 Sketch map of the Alpine belt in the Aegean region. Fig. 2. Geologic map of the Serbo-Macedonain and the Rhodope massifs in Bulgaria and Greece. Modified from Bonev et al., (2013) who used data of Ricou et al. (1998). U-Pb zircon geochronology of igneous protoliths as summarized by Bonev et al., (2013), with some recent age additions. Our st...

The Early Eocene (ca. 50 Ma) Drangovo gabbro is the most primitive member of a suite of evolved adakitic post-collisional rocks. The whole rock analysis of the gabbro: SiO2 (51.8 wt.%), Al2O3 (12.6 wt.%), MgO (8.38 wt.%), Fe2O3 (8.09 wt.%), Na2O (2.64 wt.%) K2O (1.53 wt.%) Ni-108 ppm and Cr- 327 ppm, approaches the composition of primary mantle-der...

The Early Eocene (ca. 50 Ma) Drangovo gabbro is the most primitive member of a suite of evolved adakitic post-collisional rocks. The whole rock analysis of the gabbro: SiO2 (51.8 wt.%), Al2O3 (12.6 wt.%), MgO (8.38 wt.%), Fe2O3 (8.09 wt.%), Na2O (2.64 wt.%) K2O (1.53 wt.%) Ni-108 ppm and Cr-327 ppm, approaches the composition of primary mantle-deri...

Ordovician and Carboniferous-Permian magmatism in the Sakar unit of the Sakar-Strandzha zone, Bulgaria Ордовишки и карбон-пермски магматизъм в Сакарската единица на Сакар-Странджанската зона, България Nikolay Bonev1, Petyo Filipov2, Robert Moritz3, Raya Raicheva2, Maria Borisova1 Николай Бонев1, Петьо Филипов2 , Роберт Мориц3, Рая Райчева2, Мари...

Hydrous juvenile mafic lower crust due to amphibole-bearing cumulates formation beneath arc volcanoes: preliminary study from the Upper Cretaceous subvolcanic bodies near to Praveshka Lakavitsa village, Bulgaria Водонаситена ювенилна мафична долна кора, свързана с формирането на амфиболсъдържащи кумулати под дъгови вулкани: предварителни данни от г...

This study demonstrates the importance of the process of mafic recharge in the genesis of the Zvezdel volcano and the mechanism of mixing on the basis of detailed study of mineral chemistry, melt inclusions and troctolite xenoliths. We show that variations in mineral chemistry are the result of repeated injection of basaltic magmas in an evolving a...

Post-collisional (56.0-40.4 Ma) adakitic magmatism in the Rhodope Massif and the Kraishte region, including W. Srednogorie, in South Bulgaria followed the collision of the Rhodope and Pelagonian Massifs. It forms a 250 km NW trending belt which continues into the 1000 km long belt of Eocene magmatism in northern Turkey and Iran. The rocks are repre...

The Upper Cretaceous Yambol–Burgas region of the Eastern Srednogorie continental arc is characterized by unusually large volumes of mafic shoshonitic and ultra-K magmatism represented by high-Mg cumulitic rocks, and nepheline-normative ankaramites, absarokites and shoshonitic (high-alumina) basalts. The cumulitic rocks consist of phenocrysts of cli...

The Rhodope Massif in southern Bulgaria and northern Greece hosts a range of Pb–Zn–Ag, Cu–Mo and Au–Ag deposits in high-grade metamorphic, continental sedimentary and igneous rocks. Following a protracted thrusting history as part of the Alpine–Himalayan collision, major late orogenic extension led to the formation of metamorphic core complexes, bl...

Basaltic magmatism occurred only rarely within the extensive Eocene–Oligocene volcanic activity in the Eastern Rhodope Mts., SE Bulgaria. The earliest mafic volcanism started at ca. 34 Ma with K-rich trachybasalts strongly enriched in large ion lithophile elements (LILE), particularly Ba, Sr, Pb, Th, and light rare earth elements (REE) relative to...

Cs content in interstitial glass and phenocrysts from Cs-bearing Paleogene intermediate rocks (a hyaloandesite dyke with Cs 152 ppm and a high-potassium andesite plug with Cs 143 ppm) is studied. Cs is concentrated in the groundmass glass of rhyolitic composition (an average of 360 and 760 ppm, respectively)and in some phenocrystal phases. These ar...