Irena Peytcheva

• Prof. Dr.
• Head of Department at Bulgarian Academy of Sciences

In the Posušje region of the External Dinarides (Bosnia and Herzegovina), bauxite deposits are hosted along a Late Cretaceous–Paleogene forebulge unconformity that records an extended emersion phase of the Adriatic Carbonate Platform. Historically, open-pit mining has targeted surface and shallow subsurface bauxite bodies, but ongoing exploration m...

The Kolchiko polymetallic vein-hosted mineralization is part of a broad mineralization system in the Vertiskos crustal unit in northern Greece, which includes several gneiss- and mica-schist-hosted gold, copper and antimony bearing quartz veins. Mineralization includes gold-bearing arsenopyrite and pyrite, chalcopyrite, sphalerite occurring in mass...

Deep-sea Fe-Mn polymetallic nodules formed nowadays at the deep-sea ocean floor were evaluated as promising critical raw materials (CRMs). Here, we report results of polymetallic nodules from the H22_NE block of the Interoceanmetal (IOM) exploration area in the eastern part of the Clarion–Clipperton Zone (CCZ), NE Pacific Ocean. The polymetallic no...

Assarel porphyry copper deposit is located in the Panagyurishte ore district, Central Srednogorie, which is a part of the Late Cretaceous Apuseni-Banat-Timok-Srednogorie magmatic and metallogenic belt. This study reports a new data on the epithermal high-sulfidation ore mineralization described previously as "specific" and "rare". The ore mineraliz...

Asarel-Medet JSC Mining and Processing Complex is the first, biggest and leading Bulgarian company for open pit mining and processing of copper and other types of ores. Asarel-Medet JSC is the only Bulgarian company that participates in the international research project AGEMERA to study the potential of Europe regarding critical raw materials for...

This study presents U-Pb age data obtained using an in situ LA-ICP-MS technique applied to wolframite samples from Polski Gradets (Bulgaria) and Barruecopardo (Spain). Analytical conditions were optimized using YGX2113 (wolframite) and GJ1 (zircon) natural standard reference materials (SRMs). Applying both SRMs, very similar U-Pb age results were o...

New mineralogical and geochemical data on wolframite, garnets, and scheelite (± molybdenite) in hydrothermal quartz veins and skarns from the area of the Polski Gradets ore occurrence (SE Bulgaria) are present. Wolframite is the main ore mineral partly replaced by irregular scheelite aggregates. It is mostly ferberite in composition and contains 57...

Accessory zircon is an important geochemical indicator of magma fertility in magmatic-hydrothermal deposits. It is used in ore deposit exploration due to the widely accepted consideration of the resistant zircon behavior during overprinting processes. The main purpose of present study is to investigate the geochemical characteristics of zircons in...

The trace elements composition of feldspars, both plagioclase and K-feldspar, from the Ossogovo Mountain region, SW Bulgaria, was studied with the aim to combine characteristic indicative geochemical composition with an assessment of the feldspars’ economic potential as critical raw material. The feldspars reveal higher concentrations of Sr, Pb, Ba...

The study presents new field data combined with detailed mineralogical and geochemical research of the Mn- and Fe-bearing ore occurrences located in the areas of the towns of Sliven and Yambol. The two Mn (± Fe)-bearing mineralized areas are formed in a similar position at the contact between the volcanic materials and the clayey limestones of the...

The investigated amphibolites from the Slasten lithotectonic unit are found as a strongly elongated body trending north-south at the eastern slope of the Pirin Mountain, near the village of Ilinden. These rocks are hosted by biotite and biotite-amphibole gneisses, some partially migmatized and containing thin intercalations of marble. The mineral c...

A transition towards sustainable energy sources requires the exploration and development of minerals critical to electronics and energy storage and delivery systems. Funded under Horizon Europe (Grant Agreement N°101058178), the AGEMERA project is a three-year initiative addressing critical raw materials (CRMs), including their exploration and extr...

The calcareous nannofossil assemblages in three sections (Dalgi Rid, Milkova Cheshma and Toplika) of the clayey-carbonate Mirkovo Formation in the Central Srednogorie Zone have been investigated. These sections were specifically chosen because, at their basal parts, they contain silica-manganese (± iron) mineralisations, which, according to recent...

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...

The Golden Quadrilateral of the Apuseni Mountains (Romania) represents the richest Au(-Cu-Te) porphyry and epithermal district of Europe and the Western Tethyan metallogenic belt. The Au(-Cu-Te) mineralization is associated with Neogene calc-alkaline magmatism along graben structures growing during the late stages of the Alpine-Carpathian orogeny....

The present study provides geochemical and geochronological data about Posušje bauxites in Bosnia and Herzegovina with the aim to characterize them as Critical Raw Materials (CRMs) sources and to put constraints on the time and genesis of the deposit. Boehmite is the bauxites’ main Al-bearing mineral, while gibbsite is a minor constituent. Hematite...

The concentrations of Fe, Mn, Co, Cd, Zn, Cu, Mo, and As were registered in broad intervals and are elevated compared to the mean values for the ocean water. Vertical distributions of the element concentrations in the pore waters along four sediment cores show distinct differences, mainly for the elements Fe, Mn, Cu, and Zn. Bioturbation activities...

Two diorite to monzodiorite sills are recently found among the Silurian sedimentary succession near to Asaritsa peak, West Stara Planina Mountain. Several levels with diagenetic metalliferous nodules occur within shale interval in the sediments. The magmatic rocks are affected by strong propylitic to sericitic alteration (chlorite, sericite, albite...

The study presents petrographic and compositional data of Late Cretaceous bauxite deposits in the area of Jajce, Bosnia and Herzegovina. Results indicate that bauxites exhibit ooidic to pisodic textures enclosed within a pelitomorfic matrix. Most of the deposits are boehmitic but in some localities, a considerable quantity of diaspore is identified...

Petrographic, Mineralogical and Chemical Characteristics of Bauxite from Posušje Deposits, Bosnia and Herzegovina - AGEMERA Project Research

The current study presents new mineralogical, geochemical and geochronological data for a pegmatite body hosted in gneisses and marbles from the vicinity of the Strashimir Pb-Zn vein deposit, Madan ore district, South Bulgaria. The mineral composition of the studied pegmatite is represented by oligoclase–andesine (An10.1–33.2) and albite (An0–7.6),...

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...

Increase of pollution of surface water and water sediments with hazardous substances (HSs) in the Danube River Basin requires implementation of systematic monitoring and evaluation of the sediment quality. The present study is focused on the ’South Danube’ Test Area (SDTA) that covers parts of the Lower Danube Basin in Romania, Serbia and Bulgaria....

The usual main purpose of the zircon investigation is to determine the precise age of particular rocks, applying the U-Pb isotope method. In this study we attempt to reveal the vast potential of zircons in understanding the magmatic and modification processes, as well as the structure of the deeper Earth’s interior, using the analysis of the zircon...

In the present research, we have applied a combination of Cold-CL petrography with two in-situ techniques (SEM-EDS and LA-ICP-MS) to study quartz-pyrite-sericite veins with some carbonates from the Elatsite porphyry Cu-Au deposit. Based on Cold-CL images, we found out that these veins are formed during two stages: quartz-pyrite with sericite and la...

The supply of European critical raw materials (CRMs) does not currently meet the European demand. This gap is predicted to increase, making Europe even more dependent on outside suppliers. AGEMERA is a project to help tackle this strategic problem by studying several CRM sites in Finland, Poland, Spain, the Balkans, and Zambia in different deposit...

Contact Ca-skarns are formed in the marbles of the Malyovitsa Lithotectonic Unit as a result of emplacement of crosscutting pegmatite injections in the area of the Dzhendemski Ezera, NW Rila Mt. Large (up to 4 cm), well-shaped garnet crystals dominate the mineral association with additional vesuvianite, diopside, scapolite and zoisite. Garnets were...

Global demand for critical raw materials (CRMs) continues to grow rapidly, mobilizing Europe’s domestic potential. Europe has a long tradition of mining and extractive activities of copper and base metals but is less successful in projects to source CRMs. A new Horizon Europe project called ‘AGEMERA: Agile Exploration and Geo-modelling for European...

The current study presents new geochronological and geochemical data for the Petrovitsa Pb-Zn deposit, Central Rhodopes, South Bulgaria. Based on in-situ U-Pb dating of titanites from pegmatites and skarnified mineralized marbles, it aims to provide new insights into the pegmatite formation and their relation to the hydrothermal system in the regio...

The main goal of the present study is the characterization of the mineralogical and geochemical features of polymetallic (Mn- and Fe-bearing) nodules, lens- and layer-like bodies from different localities in the central part of the Late Cretaceous Srednogorie metallogenic zone, Bulgaria. The research is based on field studies, sampling and optical...

Our study is focused on REE and yttrium (REY) geochemistry of pore waters from core-box sediments. The samples were collected from the 0–5 cm, 10–15 cm, 25–30 cm, and 35–40 cm depth intervals of four stations of the eastern part of block H_22 of IOM license area of the Clarion-Clipperton Fracture Zone, NE Pacific. The REE studies in marine pore flu...

The geochemical characteristics of the polymetallic nodules from the Interoceanmetal exploration area in the eastern part of the Clarion-Clipperton Fractures Zone (CCZ), NE Pacific are studied. The nodules are enriched in Mn and reveal an Mn/Fe ratio of 2.74-6.06, which classify them mostly as mixed hydrogenetic-diagenetic type. They are also enric...

The Karavansalija Mineralized Center (KMC) with its Au–Cu skarn mineralization associated with the Rogozna Mountains magmatic suite in southwestern Serbia belongs to the Oligocene Serbo-Macedonian magmatic and metallogenic belt (SMM-MB). Samples from intrusive and volcanic rocks at the KMC show typical arc signatures of subduction-derived magmas th...

The Gerakario Cu-Au porphyry deposit in the Kilkis ore district, northern Greece, contains epithermal quartz-stibnite veins on the eastern side of the deposit, which crosscut a two-mica gneiss. Metallic mineralization in these veins consists of stibnite + berthierite + native antimony + pyrite + arsenopyrite, and minor marcasite, pyrrhotite, chalco...

The Mn-and Fe-ore occurrences in the Panagyurishte ore region are deposited on the contact zones between Late Cretaceous andesitic breccias/andesites and reddish clayey limestones. Our working hypothesis for their genesis is in accordance with Dimitrov, Kostov (1954) considering the nodules at Toplika as initially gel-like masses, subsequently part...

The epidote-group minerals are the major hydrothermal constituent, along with titanite, chlorite, quartz, and carbonates, developed in pegmatite on the contact with marble in the vicinity of Strashimir Pb-Zn vein deposit, Central Rhodopes. The U-Pb age of titanite (39.7±1.3 Ma) fixes the time of the hydrothermal mineralization. Trace element signat...

A new approach combining geochemical and mineralogical studies with statistical methods in the Babyak Mo-Ag-Au-W-Bi-base metal deposit is presented. The data are used for 3D geological modelling of the deposit and help to better understand the zonation of the elements and the complex geological evolution of the deposit.

The growing demand on mineral resources stimulated our interest on manganese- and iron-bearing occurrences as a potential source of Mn, Cu, Ni, Co, Mo, REY, etc. Here we focus on the mineralization of the Toplika ore occurrence, which is located in the central part of the Srednogorie Zone, Bulgaria. We present preliminary data on its field relation...

We present the first apatite and zircon fission-track results coupled with new muscovite and biotite 40Ar/39Ar analysis on samples from the pre-Mesozoic granitic basement and the Upper Cretaceous to Danian volcano-sedimentary cover, which allowed us to reveal the Alpine thermal and tectonic evolution of the central parts of Sredna Gora Zone. Our ne...

The renewed importance of polymetallic nodules in the context of forecasted increasing demands for metals are discussed. Based on the Interoceanmetal Joint Organization’s (IOM) site-specific data obtained during the exploration activity in the Clarion-Clipperton Fracture Zone, a total of 272.5 Mt of nodules were estimated as economically reasonable...

Upper Carboniferous–lower Permian plutonic rocks (i.e. the Kula pluton) are exposed in Istranca (Strandja) Zone, NW Pontides on both sides of Turkish and Bulgarian border. The Kula pluton is composed of monzogranite, granodiorite, and quartzmonzodiorite facies with a medium to coarse-grained, mylonitic–blasto mylonitic texture. It was affected by l...

The economic significance of pegmatites as a source of strategic rare metals for high-tech products and green energy motivated the present study on Ta-Nb oxides from Vishteritsa rare-element beryl-columbite LCT pegmatites of the Rila-West Rhodopes Batholith in the Western Rhodopes, Bulgaria. Here, we present the first U/Pb age data from columbite w...

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...

The Vathi porphyry Cu-Au±Mo deposit is located in the Kilkis ore district, northern Greece. Hydrothermally altered and mineralized samples of latite and quartz monzonite are enriched with numerous rare and critical metals. The present study focuses on the bulk geochemistry and the mineral chemistry of pyrite, chalcopyrite, magnetite, and titanite....

Sredna Gora Zone in Bulgaria is confined between the Balkan fold-thrust belt to the north and the Rhodope metamorphic complex to the south. The pre-Mesozoic basement of the central parts of the zone consists of Variscan high-grade metamorphic rocks intruded by Late Carboniferous granitoid plutons. They are transgressively overlaid by Triassic epico...

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...

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...

Hellenic subduction system governs the entire Aegean region by creating a migrating magmatic arc since the beginning of the Early Cenozoic. The Karadağ Pluton is situated in the NW part of Turkey and represents one of the distinct snapshots of this subduction system during the Upper Oligocene - Lower Miocene period. It consists of two major litholo...

The Petrovitsa Pb-Zn deposit is located in the Madan district, Central Rhodopes. The region was one of the most important base metal producers in Europe in the past with present intensive underground activities in several mines. Rich skarn-ore metasomatic bodies and quartz-sulphide veins hosted by high-grade metamorphic rocks are the main base meta...

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

The study presents first Re-Os age data of molybdenite from the region at Babyak Mo-Ag-Au-W-Bi-base metal deposit, in combination with electron microprobe and laser ablation inductively coupled plasma mass spectrometry results for molybdenite aggregates. The Re-Os geochronology of the analyzed samples defines age at 52.6 ± 0.2 to 53 ± 0.2 Ma of the...

First data for polymetallic nodules and host sediments in Silurian sequence from the region of Asaritsa peak, West Balkan mountain are presented. The nodules are rich of Fe, Mn, Co and Ni. Both sediments and nodules have high content of REE. The described Silurian nodules and sediments show a number of similarities with modern deep-sea polymetallic...

The Öksüt high sulfidation (HS) epithermal Au (-Cu) deposit (35.32 million tonnes of ore at 1.22 g/t Au) is located in the Central Anatolian Volcanic Province (CAVP) at the south-eastern segment of the Central Anatolian Crystalline Complex (CACC). The deposit is hosted by large hydrothermal breccia bodies and hornblende-rich basaltic andesite porph...

Chelopech high-sulphidation epithermal (Cu-Au) deposit with its well-characterized hydrothermal footprint is a perfect object to test whether the geo-chemical features of alunite could be used as a reliable exploration tool. Trace element geochemistry of alunite mineralization from two locations in a suite of samples with well-preserved advance arg...

Erdenet porphyry Cu-Mo deposit is situated in the Central Asian Orogenic Belt, located north of the Tethyan tectonic domain, which formed as a result of multiple oceanic subduction events and collisions (Liu et al. 2015). Arc-magmatism resulted from the closure and subduction of the Mongol-Okhotsk Ocean under the Siberian Craton during the late Per...

Bu çalışmada, Istranca masifindeki Kula plutonunun petrojenezi ve tektonik ortamını anlamak için yeni zirkon U-Pb yaşları ve tüm kayaç jeokimya verilerini sunuyoruz. Kula plutonu Türkiye ve Bulgaristan arasındaki sınırın her iki tarafında da yüzlek vermektedir. Temsilci zirkon U-Pb yaşları 310.1 ± 2.0 My ve 298.1 ± 1.7 My (Üst Karbonifer – Alt Perm...

The study reports and discusses new LA–ICP–MS zircon U–Pb data and major and trace element analyses for 16 samples from nine different plutons intruding the Getic (Brnjica, Neresnica, Ziman, Gornjane–Tanda–Blizna), and the Danubian (Aldinac, Janja, Ravno Bučje, Plavna and Suvodol) units of the East Serbian Carpatho-Balkanides (ESCB). Within the ent...

Permian-Triassic magmatic rocks are widely exposed in different tectonic terranes and continental blocks in the Aegean region. This study is focussed on the İstanbul Zone and the Istranca (Strandja) Massif, which are located in the Western Pontides of NW Turkey. The Kırklareli and the Tepecik plutons intruded into the metamorphic basement rocks of...

In the original version of this article, one reference was incorrect. The following change was necessary:

Formation and evolution of the Pannonian Basin as part of the Mediterranean region was accompanied by eruptions of compositionally diverse magmas during the Neogene to Quaternary. The long-lasting magmatic activity began with some of the most voluminous silicic eruptions in Europe for the last 20 Myr. This paper describes the eruption chronology of...

We report new U-Pb zircon ages, major and trace element data, mineral chemistry and Sr–Nd isotopic analyses of the mafic – intermediate dykes and intrusions in the İstanbul zone. Mafic dykes are represented by calc-alkaline to alkaline lamprophyre and diabase. Intermediate dykes and sub-volcanics are andesitic to dacitic in composition and calc-alk...

In the present study, we apply a combination of Sr-isotope whole-rock analyses and LA-ICP-MS U-Pb zircon dating to understand the magmatic evolution of the igneous rocks in the Ruen Zone, western Bulgaria, and bracket the time of their formation. This approach reveals a general interval of magmatic activity from 35.57 ± 0.27 Ма (Pishtilski volcanic...

We report new U–Pb zircon ages, major and trace element data, mineral chemistry, and Sr–Nd isotopic analyses of the mafic–intermediate dykes and intrusions in the İstanbul Zone. Mafic dykes are represented by calc-alkaline to alkaline lamprophyre and diabase. Intermediate dykes and subvolcanics are andesitic to dacitic in composition and calc-alkal...

In this paper, we present detailed field observations, chronological, geochemical and Sr–Nd isotopic data and discuss the petrogenetic aspects of two types of mafic dykes, of alkaline to subalkaline nature. The alkaline mafic dykes exhibit a cumulate to foliated texture and strike NW–SE, parallel to the main trend of the region. The 40Ar/39Ar amphi...

Upper Cretaceous volcano-sedimentary sequences of the Eastern Pontide orogenic belt, NE Turkey, are host to significant VMS mineralization, including near Tunca. The initial stages of felsic volcanism within the mineralized area are marked by the eruption of dacitic lavas and breccias of the Kızılkaya Formation. This was accompanied by the emplacem...