Ivan Zagorchev

• Doctor of Geological Sciences
• Professor Emeritus at Bulgarian Academy of Sciences

Abundant evidence gathered mostly during the present century proves the presence of the Cadomian and Caledonian s.l. (Cenerian) orogenies within the northern margin of Gondwana,-within the Thracian and Balkan terranes. The detailization of the Early Paleozoic evolution of the Balkan Peninsula should be further developed with the joint efforts of th...

About 50 years ago, the study of geology has been removed from the curricula of the Bulgarian secondary education system. The young generations have to receive from the Geography textbooks (centred more on Human Geography) only unsystematic knowledge about some physical geographical features related to geological processes and structures, as the ge...

GEOGRAPHY OR EARTH SCIENCES (GEOSCIENCES) IN THE BULGARIAN SECONDARY EDUCATION? The paper discusses the knowledge gaps in secondary (high school) education in Bulgaria in respect to the Earth Sciences, and the necessity to introduce a systematic education system in this area of knowledge. The principal geological, mineralogical-geochemical, and geo...

The uppermost parts of the Lower Drimos Limestones from the section at Karpenission contain a rich conodont assemblage corresponding to the middle parts of the Sevatian Epigondolella bidentata R. Z. It is dominated by the species Misikella postlzernsteini Kozur & Mock and Paragondolella steinbergensis Mosher, and contains the new conodont species E...

In the present paper, we consider all activities and institutions related to the complex system of the hard Earth as a complex national system. This Geoscience System (Complex) embraces educational institutions (schools of all degrees), research institutions, NGOs, and the National Geological Survey. They all are of paramount importance for the nor...

The tectonic subdivision of a given territory should be based on thorough field work, as a synthesis of its principal results and of the bulk of tectonic and stratigraphic knowledge on this territory. It should serve together with litho-and chronostratigraphy as a basic framework both for future mapping and prospection, and for metallogenic, hydrog...

Presentation to the XXII International CBGA Congress on the 100th Anniversary of CBGA - a successful geoscientific project in a dramatically changing geopolitical environment

Abstract of presentation on the 100th Jubilee of the CBGA

History as any other science is dedicated to the search of Truth. However, different factors as the losses of historical sources (documents); biases in historical sources, including their fabrication and/or counterfeiting; biases in the interpretations due to the cultural and national background of the researchers or to strong political, nationalis...

Presentation at the National Conference Geosciences'2021

Academician Todor Nikolov is the most outstanding Bulgarian geologist of the last decades. His contributions in the geosciences cover a vast field of paleontology and stratigraphy with emphasis on the Late Jurassic and Early Cretaceous of the Mediterranean realm. As University teacher, editor and reviewer, he has been instrumental in the developmen...

Problems of the Cimmerian igneous activity are briefly discussed at the background of the plate tectonics of the Balkan Peninsula. We mostly comment on the relations of the tectonometamorphic evolution of the Bulgarian territory with the Vardar Ocean and its subduction beneath the European continent. A number of problems still remain open especiall...

Problems of the Cimmerian igneous activity are briefly discussed at the background of the plate tectonics of the Balkan Peninsula. We mostly comment on the relations of the tectonometamorphic evolution of the Bulgarian territory with the Vardar Ocean and its subduction beneath the European continent. A number of problems still remain open especiall...

Problems of the quality of science are discussed. We concentrate on the concrete and abstract-concrete sciences of H. Spencer’s classification. As far as science is a system of logically and experimentally verified facts, interpretations, hypotheses and models, i.e., a system of scientific truths, the problem of its quality is irrelevant. However,...

We report a major olistostromal event situated around the Priabonian/Rupelian boundary. It is manifested in the island of Samothraki simultaneously with the development of a carbonate reef, preceded and followed by flyschoid sedimentation. Olistostrome formation of approximately the same age is observed also in the SE part of the island of Lemnos....

Presentation to the IESCA 7 meeting in 2019, Izmir

The existing practice for characterizing the time of a metamorphic event by the average mean of radiogenic mineral dates gives a false idea about the event duration. In the present communication this practice is discussed from the viewpoint of regional geology and geodynamics. Conclusions about the interpretations of radioactive mineral dates for t...

Presentation given online at the GEOSCIENCES'2020 Conference. Comments the importance of estimation of the geologic event duration and the related problems of LA-IPC_MS U-Pb geochronology. Two examples from SW Bulgaria (Ograzhdenian polymetamorphic supercomplex in the Ograzhden unit, Serbo-Macedonian massif, and Rhodope polymetamorphic supercomplex...

LA-ICP-MS U-Pb геохронология по монацит: геоложка "дата" и времетраене на геоложко събитие. Коментар върху статията на Х.-Й. Масон, European Journal of Mineralogy, Резюме. Коментира се статия върху една единствена проба от метапелити, принадлежащи на Луковишката свита от Пирин-Пангеонската единица. Посочват се несъответствия на интерпретациите на а...

The structure of the Balkan Peninsula is dominated by the Alpine (Alpidic) mountain chains: Carpathians–Balkan (Stara planina), Serbo-Macedonian–Rhodopes, and Dinarian–Albanian–Hellenic. These contain fragments from Precambrian (mostly late Neoproterozoic) and Paleozoic tectonometamorphic units that underwent strong reworking during the Hercynian a...

The Bulgarian Academy of Sciences and the development of geosciences in Bulgaria Dedicated to the 150th anniversary of the Bulgarian Academy of Sciences

The philosophy of a given natural science consists of its basic methods, ideas, paradigms and implications. The present contribution aims to expose and discuss some of the fundamentals of the geology of the Rhodopes in the light of the modern geological paradigms but also taking into considerations the basic achievements of the past more than 150 y...

Problems of the quality of science are discussed. We concentrate on the concrete and abstract-concrete sciences of H. Spencer’s classification. As far as science is a system of logically and experimentally verified facts, interpretations, hypotheses and models, i.e., a system of scientific truths, the problem of its quality is irrelevant. However,...

We discuss the erroneous introduction in geological publications of the term "violin breccia" as a synonym of "fault-bound sedimentary breccia". The term is borrowed by some Bulgarian authors from the formal lithostratigraphic unit Violin Breccia, Southern California. There are no grounds to apply it as a sedimentological term to beds and strata-bo...

Recent pioneer light element stable isotope and 87Sr/86Sr studies on Rhodopes marbles are discussed. The number and localities of the samples (3 locations in the Asenitsa unit, and 3–4 locations in the Pirin unit) are insufficient for sound interpretations. The 87Sr/86Sr ratios determined for marbles from the Asenitsa and Pirin units do not show su...

The presentation describes briefly the layered metamorphic lithostratigraphic units in the Rhodopes massif, and explains why they cannot be referred to as "melanges"

PSEUDOSCIENCE AND PSEUDOJOURNALISM: FABRICATED AND FALSIFIED “SCIENCE” DATA, CHEAP SENSATIONS AND FAKE NEWS (Abstract) The problems of the integrity in science are an important theme of numerous publications and codes of science ethics. In the present paper differences between the scientific misconduct (fabrication of data, falsification of data, p...

The presentations explains the principal differences between pseudoscience and research misconduct. The main features of pseudoscience are outlined as well as the patterns of pseudoscience publicity, and the legal and institutional problems when struggling with pseudoscience. A comparison between pseudoscience and pseudojournalism is made.

We describe the oldest known European ruminant, Bachitherium thraciensis sp. nov., from late Eocene (latest Bartonian or early Priabonian) strata in Bulgaria. The new specimen, which possesses the most primitive dental morphology known in the Bachitheriidae family, predates its western European relatives by at least 4.5 myr. The discovery suggests...

Key stratigraphic and tectonic problems of the pre-Alpine geology within the border area between Bosilegrad and Vlasina (Serbia) and Treklyano and Zemen (Bulgaria)

Comments are made on studies performed by D. Kozhoukharov, B.V. Timofeyev and M. Konzalova on the microphytopalaeontologic and biostratigraphic evidence in amphibolite-facies complexes in the Rhodopes Massif in Bulgaria, and their chronostratigraphic interpretations published between 1979 and 1994. Microphytofossils (acritarchs) determined from the...

To the memory of Prof. Stephen Erwin Moorbath, F.R.S. Abstract. New isotopic data obtained from zircons by the U-Pb method during the last decade show the necessity of a revision of the tectonometamorphic and igneous evolution of the Pirin–Pangaion Unit of the Alpine Morava–Rhodope tectonic zone. The northern (Pirin) subunit of this unit consists o...

Keywords: Pirin-Pangaion unit, Cadomian origin, Hercynian metamorphism and anatexis, Permo–Triassic and Palaeogene granitoid magmatism. The Pirin-Pangaion tectonic unit has been introduced (Zagorčev, 1994) as the lowermost tectonic unit within the Rhodopes tectonic edifice. Recently published U-Pb isotopic data on zircons (Machev, Ovtcharova, 2008;...

Presentation (English version) about the 150 Anniversary of the birth of the Patriarch of the Bulgarian mineralogy and petrology, Academician Georgi Bonchev

Polyphase tectonometamorphism is one of the principal characteristics of the Rhodope Massif. Therefore, major controversies exist in the interpretations of every aspect of its evolution: (1) primary composition, character and age of the protoliths; (2) tectonometamorphic evolution, age of the principal and of superimposed events; (3) deformations a...

This is the presentation given on December 10, 2015. It is added to the extended abstract of the same name.

U-Pb isotopic data obtained during the last decade on zircons from the Prerhodopian and Rhodopian metamorphic supercomplexes in the Rhodope massif indicate at several major epochs of metamorphism and anatexis: Cadomian, Hercynian, Middle to Late Jurassic, and Palaeogene. Events of Ordovician- Silurian and Late Cretaceous ages are also locally recor...

The Frolosh Greenstone Belt (FGB) is traced at a distance of more than 200 km in the territories of Bulgaria, Macedonia and Serbia. It consists of various greenschist-facies rocks (actinolite schists, phyllites, calcareous schists, impure marbles, metasandstones, metadiabases, massive green rocks, etc.) of the Frolosh metamorphic complex with bodie...

Academic lecture at the Bulgarian Academy of Sciences

Since the discovery of calcareous nannofossils, dinoflagellate cysts and planktonic foraminifers in deposits from the Dacic Basin, intensive research has been performed in order to evidence which gateway this microplankton used to connect Paratethys and the Mediterranean prior and after the Messinian Salinity Crisis (MSC). Such a gateway is also to...

Presentation at the First Congress of Macedonian geologists, Ohrid 2008

Presentation at the session in honour of D. Kozhoukharov within the frame of the Scientific Seminar of the Geological Institute of the Bulgarian Academy of Sciences.

Since the discovery of calcareous nannofossils, dinoflagellate cysts and planktonic foraminifers in deposits from the Dacic Basin, intensive research has been performed in order to evidence which gateway this microplankton used to connect Paratethys and the Mediterranean prior and after the Messinian Salinity Crisis (MSC). Such a gateway is also to...

Key words: Palaeocene–Ipressian, Lutetian, Priabonian–Rupelian magmatism. The modern approach to the late Alpine igneous evolution of the Rhodopes region is related to the recognition and establishment with viable arguments of the presence of widespread intrusive activity throughout the Palaeogene Period together with the well-known Priabonian and...

A gabbro-norite body in the Ograzhdenian supercomplex bears traces of several phases of zircon formation. TIMS and LA-ICP-MS zircon age dating yielded a considerable number of ancient zircon crystals scattering between c. 2600 Ma and 565 Ma. Discordant xenocrysts cannot define a single perfect Discordia line although an upper intercept of a referen...

Abstract. A gabbro-norite body in the Ograzhdenian supercomplex bears traces of several phases of zircon formation. TIMS and LA-ICP-MS zircon age dating yielded a considerable number of ancient zircon crystals scattering between c. 2600 Ma and 565 Ma. Discordant xenocrysts cannot define a single perfect Discordia line although an upper intercept of...

Presentation at the Workshop - s. the abstract of the same title

The Krupnik granite pluton is emplaced into amphibolite-facies metamorphic rocks referred to the Rhodopian metamorphic supercomplex (Rupchos/ Predela complex) in the northernmost parts of the Pirin–Pangaion unit. The age of both the pluton and of its host rocks has been a subject of controversies. Isotopic studies on zircons prove a Triassic age fo...

The Messinian Salinity Crisis is well known to have resulted from a significant drop of the Mediterranean sea level. Considering both onshore and offshore observations, the subsequent reflooding is generally thought to have been very sudden. We present here offshore seismic evidence from the Gulf of Lions and re-visited onshore data from Italy and...

Upper Oligocene – Lower Miocene marine sediments are found and proven for the first time in Chalkidiki Peninsula. They are designated as Siviris Formation and are dated by their calcareous nannofossil content.

Basement complexes The pre-Palaeogene basement of Samothraki Island consists (Davis, 1963; Heimann et al., 1972; Tsikouras, Hadzipanagiotou, 1995; Koglin et al., 2009) of Jurassic ophiolites (mostly basaltic pillow lavas), an igneous suite (160 to 150 Ma) that ranges from gab-bro to plagiogranite, and a metasedimentary complex (greenschist-facies m...

The geomorphological zonation of Bulgaria derived from the morphotec-tonic zonation was first introduced by Cviji. Although the morphotectonic zonation remained in the basis of the geomorphological and neotectonic maps, during their evolution they included numerous elements typical of the mor-phostructures and morphosculptures (for the geomorpholog...

The geomorphological zonation of Bulgaria derived from the morphotec-tonic zonation was first introduced by Cvijic ́. Although the morphotectonic zonation remained in the basis of the geomorphological and neotectonic maps, during their evolution they included numerous elements typical of the mor-phostructures and morphosculptures (for the geomorpho...

The evolution of the ideas about the basement complexes on the Balkan Peninsula has developed from the initial attribution to a single and uniform Precambrian complex towards differentiation, and recognition of different protoliths that underwent polymetamorphic and multi-deformational histories. Correlation between metamorphic complexes distinguis...

A Gilbert-type fan delta has been evidenced in the Pliocene sediments southward Skopje at Dračevo. As such sedimentary constructions result from the effects of the Messinian Salinity Crisis, it is demonstrated that the Messinian Salinity Crisis impacted the region of Skopje as it did for the northern Aegean region (Thessaloniki) and Western Dacic B...

The Upper Cretaceous sediments in Krayshte area are reported to have a wider distribution than previously considered. They are dated using calcareous nannofossils, proving the presence of different parts of the Campanian Stage. Four new formal lithostratigraphic units are introduced and characterized. The Gorna Koznitsa Formation consists of coarse...

Polymetamorphic amphibolite-facies complexes are exposed in the eastern and central parts of the Balkan Peninsula in different Alpine tectonic zones and under different Cadomian to Alpine collisional and exhumation histories and regimes. All complexes consist mostly of biotite and two-mica gneisses and schists, and amphibolites. Strong Cadomian ove...

The Strouma and Mesta are two of the largest rivers that drain across SW Bulgaria and northern Greece into the northern Aegean Sea. Their modern valleys, flanked by Quaternary river terraces, are incised into a diverse landscape, which records the region's complex tectonic history. A network of lacustrine basins existed in the region in the Late Ol...

The Moesian Group consists of terrigenous and carbonate red beds of different lithology. Conglomerate and sandstone of various pebble and grain size are interbedded with siltstone, shale and marl. Limestone or dolomite interbeds are also observed as well as lenses and concretions of anhydrite, and halite bodies. The formations of the group are refe...

A presentation on the occasion of 100 years since the birth (1907) of the remarkable Bulgarian regional geologist and tectonician, Acad. Prof. Dr Ekim Bončev. In Bulgarian. It is published now on ResearchGate on the occasion of the 110 years’ jubilee, and 70 years since the foundation of the Geological Institute of the Bulgarian Academy of Sciences...

The notion of Kraishtides underwent considerable transformations during 70 years since its introduction in the tectonic nomenclature of the Balkan Peninsula. Initially it was introduced for the allegedly youngest (Early Miocene) fold and thrust (orogenic) zone (Krajštiden) situated obliquely to Balkanides and South Carpathians. This notion evolved...