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GEOLOGICA BALCANICA, 46 (1), Sofia, July 2017, pp. 109–113.

In memoriam

Professor Nikola Angelov Jolkichev, DSc(July 16, 1925 – August 8, 2017)

One of the greatest Bulgarian palaeontologists and stratigraphers, and a long-time teacher of geology, Professor Nikola Jolkichev, DSc, passed away on Au-gust 8, 2017, at the age of 92. His colleagues, collabo-rators, and students will retain the memory of a tire-less researcher with profound knowledge of the Up-per Cretaceous geology of Bulgaria. During the entire time of his professional career, Prof. Jolkichev proved to be a precise worker, but also a correct and respon-sive man who was always ready for cooperation and constructive dialogue and who never hesitated to offer help and advice to his younger colleagues.

Professor Nikola Jolkichev was born on July 16, 1925, in the mountain village of Chuprene (Belograd-chik area, Vidin District, NW Bulgaria), into a modest peasant family. He completed his primary education in his native village. At the age of 14, he worked as an assistant to his uncle in Sofia, where he graduated from high school. Following his first passion, music, in 1951 he successfully applied and was enrolled in the Bulgarian State Conservatoire with opera sing-ing (bass-baritone). However, one year later, on the advice of his relatives, Nikola Jolkichev applied and was admitted to Sofia University (Faculty of Biology, Geology and Geography), from where he graduated in 1957 as a geologist. In the same year, he became an Assistant Professor at the Department of Dynamic and Historical Geology of Sofia University, where he was successfully promoted and continued working until his retirement in 1991. Following the advice of Acad. Ekim Bonchev, he began studying stratigraphy and fossils of the Upper Cretaceous sediments in Bulgaria. Along with that, Nikola Jolkichev guided students’ practical classes of Introduction to Geology, Histori-cal Geology, and Geology of Bulgaria, as well as the basic course of Stratigraphy of Bulgaria. His PhD the-sis “Stratigraphy of the Coniacian–Maastrichtian sed-iments of the central parts of the Fore-Balkan and the Moesian Platform” was defended in 1972. Soon after that, Nikola Jolkichev went for three years to Cuba, where he took part of the Bulgarian geological expe-dition in the province of Las Villas. Upon his return from Cuba, he continued his research and teaching ac-

tivities at Sofia University and defended his DSc the-sis entitled “Stratigraphy of the North European type Upper Cretaceous in the area of the Balkanides and the Moesian Platform, to the east of the Ogosta River” on May 15, 1985. In March 1973, Nikola Jolkichev became an Associate Professor at the Department of Dynamic and Historical Geology, and then he was promoted to full Professor at the same department, in February 1987. In his work and collaborations, he used freely several languages: Russian, English, Ger-man, and Spanish.

Professor Jolkichev left a valuable scientific leg-acy, having authored a monograph and authored (co-authored) about 50 research articles over a 50-year period. Professor Jolkichev’s thematic focus was mainly on the stratigraphic distribution of the Upper Cretaceous fossils (e.g., inoceramid bivalves, ammo-nites, belemnites, and echinoids), of which he col-lected spectacular collections and recognized several new species that have been recorded in many localities

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around Europe ever since. He made his first steps by studying the Lower Cretaceous strata of Urgonian fa-cies in the area of the Cherepish Monastery (West Bul-garia), but his main contributions are entirely devoted to the stratigraphy of the Upper Cretaceous rocks in Bulgaria. Professor Jolkichev began his career with systematical studies of the epicontinental Upper Cre-taceous deposits of the Western Srednogorie, where he recognized and described the Turonian, Santonian, Campanian, and Maastrichtian within several offi-cially introduced lithostratigraphic units. In the Upper Cretaceous outcrops of the Kondel Hill, near the town of Dragoman, he discovered, in collaboration with his graduate students, the presence of Coniacian–Santo-nian sediments, which lie unconformably upon the rocks of the Barremian. Professor Jolkichev specified the age of the upper Santonian sediments in the West-ern and Central Fore-Balkan (in Mezdra area and the area south of the town of Pleven) that had previously been assigned to the Maastrichtian and also proved

the presence of lower and upper Campanian strata in this region. Based on the combined study of macro- and microfossils, he determined the boundaries and the extent of the Coniacian and the Santonian of the Nikopol area and proved the presence of upper Cam-panian sediments in the Upper Cretaceous sequences in front of the Stara Planina Thrust in the Central Bal-kan Mts. He also dated as late Campanian the rocks of the northern limb of the Gabrovo syncline (Central Bulgaria) and recognized the Campanian amongst the sequences of the eastern part of the Dobrudza Basin (NE Bulgaria) that had previously been thought to be of Santonian age. Summarizing the observation of his numerous field trips and subsequent analyses, Nikola Jolkichev gradually established 21 formal lithostrati-graphic units (formations), which are now an integral part of the formal lithostratigraphic scheme for the Upper Cretaceous in Bulgaria. Especially significant is Prof. Jolkichev’s contribution to the palaeogeogra-phy of the land of present-day North Bulgaria during

Field pictures of some Upper Cretaceous lithostratigraphic units of Mezdra area (West Bulgaria), established and studied by Jol-kichev (1986) (1–4): 1) The boundary between the Darmantsi and Kunino formations near Darmantsi Village; 2) The stratotype section of the Kunino Formation at Kunino Village; 3) Detail from the stratotype section of the Rumyantsevo Formation south of Rumyantsevo Village; 4) Discussion at the section near Moravitsa Village with Jaume Gallemi (Museu de ciències naturals de Barcelona) (photo: Neda Motchurova-Dekova).

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the Late Cretaceous (Nikolov, 2015). For instance, he recognized that the Cenomanian marine transgression took place from the east to the west in NE Bulgaria, via flooding the downgraded sectors of the Lower Cre-taceous relief. Additionally, he confirmed the data of previous authors, according to whom the Cenomanian basin in the central parts of the Moesian Platform suc-ceeded the Albian basin. Professor Jolkichev found that the transgression of the Late Cretaceous Epicon-tinental Sea continuously expanded to the south, from the late Turonian to the Maastrichtian, having a maxi-mum at the late Maastrichtian, but then followed by a prominent tectonic rise that reduced the marine sedi-mentation to the areas of the Lom Depression and the Dobrudza Plateau. He recognized many regional gaps in the Upper Cretaceous sequences, associated with hard grounds, which have been proved to be important markers and palaeogeographic indicators.

We had the chance to meet Prof. Jolkichev in the late 1990s, when he had already retired but still con-tinued to come to his office in Sofia University to fol-low his rich scientific correspondence with foreign geologists and palaeontologist and to pursue the work on some of his last papers up to his late eighties. In the last several years, he encouraged us to work on the Campanian–Maastrichtian fossil assemblages of the Mezdra area. Professor Jolkichev always impressed us

with his wide knowledge and interests. We are forever indebted to him for his unstinted guidance, friendship, and help. Furthermore, during his career, he main-tained close relationships and generously shared his knowledge with several foreign colleagues and stu-dents. On numerous occasions, he warmly welcomed them and volunteered to serve as an experienced guide during field trips in Bulgaria.

Nikola Jolkichev had, above all, an extremely mod-est, honest, earnest, and very humane personality as a geologist, prominent scientist, colleague, and teacher. We feel that he will always be alive in the memory of many of us, and we will preserve our admiration for him as both a personality and geologist. The society of the Bulgarian geologists extends their deepest con-dolences and sympathies to the family of Prof. Nikola Jolkichev. He will be greatly missed. Prof. Jolkichev will remain in the history of Bulgarian geology and in the hearts of everyone who has the privilege to have known him.

REFERENCES

Nikolov, T. 2015. Prof. Nikola Jolkichev, DSc, at the age of 90 – an uneven but dignified way of life. Review of the Bul-garian Geological Society 76 (1), 157–159 (in Bulgarian).

Lubomir Metodiev, Docho Dochev

CONTRIBUTIONS OF PROF. NIKOLA JOLKICHEV

Jolkičev, N. 1959. Bemerkungen über das Alter der Kalk-steine von der Umgebung des Klosters Čerepič. Annuaire de l’Université de Sofia, Faculté de Biologie, Géologie et Géographie 53 (2), 273–277 (in Bulgarian, with German abstract).

Jolkičev, N. 1962. Inoceramen aus dem Maastricht Bulgariens. Travaux sur la géologie de Bulgarie, Série Paléontologie 4, 133–169 (in Bulgarian, with German abstract).

Jolkičev, N.A. 1962. Inoceramids from the Santonian sediments of the Melovete Hill, Dimitrovgrad District (People’s Re-public of Bulgaria). Vestnik Moskovskogo Universiteta 5, 30–33 (in Russian).

Jolkičev, N.A., Karagiuleva, Y. 1962. Stratigraphy of the Up-per Cretaceous along the “Melovete” elevation near the town of Breznik. Travaux sur la géologie de Bulgarie, Sé-rie Stratigraphie et Tectonique 4, 117–132 (in Bulgarian, with English abstract).

Jolkičev, N.A. 1964. Über die Anwesenheit Campanischer Ablagerungen im Gebiet von Pleven. Bulletin of the Geo-logical Institute 13, 169–179 (in Bulgarian, with German abstract).

Belmoustakov, E., Jolkičev, N. 1965. La stratigraphie du Maëstrichtien et du Thanetien dans le synclinal de Gabrovo (Bulgarie du nord). Travaux sur la géologie de Bulgarie, Série Stratigraphie et Tectonique 6, 177–194 (in Bulgarian, with French abstract).

Jolkičev, N.A. 1967. Über die Anwesenheit der Santonis-chen Stufe im Vorbalkan zwischen den Flüssen Skăt und Černelka (Nordbulgarien). Bulletin of the Geological In-stitute, Series Geotectonics, stratigraphy and lithology 16, 187–197 (in Bulgarian, with German abstract).

Jolkičev, N.A., Ninov, P., Penčev, P. 1968. Über die Anwesen-heit von Coniac- und Santonablagerungen im Kreis Drago-man. Review of the Bulgarian Geological Society 29 (3), 325–329 (in Bulgarian, with German abstract).

Jolkitschev, N., Vaptzarova, J. 1969. Über die Anwesenheit der Campanichen Stufe im Vorbalkan zwischen dem Skăt und Katunetzka Fluss. Annuaire de l’Université de Sofia, Fac-ulté de Géologie et Géographie 61 (1), 81–104 (in Bulgar-ian, with German abstract).

Jolkičev, N. 1970. Coniac–Santonischen Sedimente und ihre Echinidenfauna Nördlich vom Dorf Novačene, Bezirk Pleven. Annuaire de l’Université de Sofia, Faculté de Géologie et Géographie 62 (1), 73–84 (in Bulgarian, with German abstract).

Jolkičev, N. 1971. Neue Angaben über die Stratigraphie und den Umfang der Kampan–Stufe des Schumen–Plateaus. Annuaire de l’Université de Sofia, Faculté de Géologie et Géographie 63 (1), 61–66 (in Bulgarian, with German ab-stract).

Jolkičev, N. 1971. On the presence of Upper Campanian sedi-ments at Beloslav Village, Varna District. Review of the

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Bulgarian Geological Society 32 (2), 248–250 (in Bulgar-ian, with English abstract).

Jolkičev, N.A. 1971. Stratigraphy of the Coniacian–Maast-richtian sediments in the central part of the Fore-Balkan and the Moesian Platform. PhD thesis, Sofia University “St Kliment Ohridski”, 291 pp. (in Bulgarian, unpub-lished).

Jolkičev, N. 1978. Bohrmuschel in den Campanischen und Maastrichtischen Ablagerungen zwischen den Dörfern Debovo und Musselievo, Kreis Pleven. Annuaire de l’Université de Sofia, Faculté de Géologie et Géographie 70 (1), 87–92 (in Bulgarian, with German abstract).

Jolkičev, N. 1978. Jurassic and Cretaceous inoceramid species in Bulgaria. In: Pergament, M.A. (Ed.), Jurassic and Creta-ceous inocerams and their stratigraphic importance. (Ma-terials of the IIIrd and IVth All–Union Colloquium). Acad-emy of Sciences of the USSR, Order of the Red Banner of Labor, Geological Institute, 69–76 (in Russian).

Jolkičev, N.A. 1980. Stratigraphie der Coniac–Maastricht–Ab-lagerungen in den Zentralteilen des Vorbalkans und der Mösischen Platte. Annuaire de l’Université de Sofia, Fac-ulté de Géologie et Géographie 72 (1), 5–78 (in Bulgarian, with German abstract).

Jolkičev, N. 1980. Upper Cretaceous. In: Atanasov, A. (Ed.), Hydrocarbon potential of the Fore-Balkan. Tehnika, Sofia, 18–19 (in Bulgarian).

Jolkičev, N. 1981. Stratigraphy of the Upper Cretaceous in Stara Planina granite thrust fault area (Central Stara Plan-ina Mountain). In: Stoyanov, S., Pironkov, P. (Eds), Fold-thrust composition of the central part of the Stara Planina Mountain. Bulgarian Academy of Sciences. IX Problem-atic International Commission of Soviet Union Academy of Sciences “Geosyncline process and the Erath core struc-ture”, Sofia, 57–72 (in Russian).

Jolkičev, N., Pironkov, P. 1981. Lithostratigraphical notes of Paleogene in Kalofer part of Stara Planina Mountain. In: Stoyanov, S., Pironkov, P. (Eds), Fold-thrust composi-tion of Central part of Stara Planina Mountain. Bulgarian Academy of Sciences. IX Problematic International Com-mission of Soviet Union Academy of Sciences “Geosyn-cline process and the Erath core structure”, Sofia, 73–78 (in Russian).

Dimitrova, E.N., Ganeva, N.T., Jolkičev, N.A., Milanova, J.N., Nachev, I.K. 1981. Upper Cretaceous stratigraphy in West-ern Srednogorie. Geologica Balcanica 11 (1), 51–66.

Jolkichev, N. 1982. Upper Cretaceous Stratigraphy in the Area of Stara Planina Granite Nappe (Central Stara Planina). Re-view of the Bulgarian Geological Society 43 (1), 25–40 (in Bulgarian, with English abstract).

Jolkičev, N. 1983. Upper Cretaceous. In: Atanasov, A., Bokov, P. (Eds), Geology, oil and gas perspectives of the Moesian Platform in Central North Bulgaria. Tehnika, Sofia, 38–44 (in Bulgarian).

Jolkichev, N., Dimitrova, E. 1983. Campanian sediments in Varna Plateau. Review of the Bulgarian Geological Society 34 (1), 1–7 (in Bulgarian, with English abstract).

Jolkičev, N.A. 1984. Stratigraphy of the North European type Upper Cretaceous in the area of the Balkanides and the Moesian Platform to the east of the Ogosta River. Part I, 179 pp.; Part II, 536 pp. DSc thesis, Sofia University “St Kliment Ohridski” (in Bulgarian, unpublished).

Yolkichev, N., Moskovski, S. 1985. Olistostromes of Upper Cretaceous limestones in the Lower and Middle Eocene in Provadiya Plateau. Annuaire de l’Université de Sofia “St Kliment Ohridski”, Faculté de Géologie et Géographie 79 (1), 3–13 (in Bulgarian, with English abstract).

Jolkičev, N.A. 1986. Lithostratigraphic units related to the Up-per Cretaceous in the West and Central Fore-Balkan. Re-

view of the Bulgarian Geological Society 47 (3), 49–61 (in Bulgarian, with English abstract).

Yolkichev, N., Stoyanova-Vergilova, M. 1986. Stratigraphic ad-herence of the Upper Cretaceous Belemnitellidae in North Bulgaria. Annual of the Higher Institute of Mining and geo-logy 32 (2), 25–36 (in Bulgarian, with English abstract).

Jolkičev, N.A.1987. Lithostratigraphic units, related to the Up-per Cretaceous Series in the central part of the Moesian Platform. Review of the Bulgarian Geological Society 43 (1), 102–112 (in Bulgarian, with English abstract).

Jolkičev, N. 1987. Cretaceous System – Upper Cretaceous Se-ries. In: Bokov, P., Chemberski, H. (Eds), Geological con-ditions for hydrocarbon potential of Northeast Bulgaria. Tehnika, Sofia, 91–98 (in Bulgarian).

Moskovski, S., Yolkichev, N. 1987. Gravity-nappe struc-ture of Lozen Mountain and Vakarel ridge. Annuaire de l’Université de Sofia, Faculté de Géologie et Géographie, 81 (1), 11–30.

Jolkičev, N.A. 1988. Lithostratigraphic units related to the Up-per Cretaceous Series in the eastern parts of the Moesian Platform. Review of the Bulgarian Geological Society 49 (1), 11–25 (in Bulgarian, with English abstract).

Jolkičev, N.A., Jovcheva, P., Dimitrova, E., Stojanova-Vergilo-va, M. 1988. Stratigraphy of the Cenomanian Stage north of Pleven and new microfaunistic data on its basement. Re-view of the Bulgarian Geological Society 49 (2), 24–36 (in Bulgarian, with English abstract).

Jolkičev, N.A. 1989. Stratigraphy of the epicontinental type Upper Cretaceous in Bulgaria. “Kliment Ohridski” Uni-versity Press, Sofia, 184 pp. (in Bulgarian, with Russian and English abstracts).

Jolkičev, N. 1990. On “zonal” subdivision of the Upper Creta-ceous Series in Northeastern Bulgaria. Review of the Bul-garian Geological Society 51 (3), 105–108.

Jolkičev, N. 1993. Asparuhovo Limestone Formation; Ven-chan Limestone Formation; Dobrin Dol Glauconite-sandy-limestone Formation; Dobrina Sandy-limestone Formation; Darmantsi Glauconite-sandy-limestone Formation; Kay-laka Limestone Formation; Kalena Bioclastic-limestone Formation; Kunino Limestone Formation; Madara Sandy-limestone Formation; Mezdra Flint-limy Formation; Mog-ilena Flint-limestone Formation; Murna Limestone Forma-tion; Nikopol Bioclastic-limestone Formation; Novachene Marly-limestone Formation; Rumyantsevo Limestone For-mation; Sanadinovo Marl Formation; Byalo Bardo Glauc-onite-sandy-limestone Formation; Shumen Formation. In: Tenchov, Y. (Ed.), Glossary of the formal lithostratigraph-ic units in Bulgaria (1882–1992). BAS Publishing House, Sofia, 397 pp. (in Bulgarian, with English abstract).

Stoyanova-Vergilova, M., Jolkičev, N. 1993. Representatives of the genus Belemnitella of Bulgaria (Upper Cretaceous). Geologica Balcanica 23 (4), 25–53.

Jolkichev, N. 1998. Critical remarks on the paper Mileva-Ilieva, T. Gacheva, R. 1993. Additional regular echinids from the Upper Cretaceous – representatives from genus Porosoma. Annual of the University of Mining and Geol-ogy, vol. 39, part I, Geology, Sofia; 7–10. Geologica Bal-canica 28 (1–2), 71–72.

Jolkichev, N.A., Naidin, D.R. 1998. The Upper Cretaceous of North Bulgaria, Crimea and Mangyshlak. Article 1. Upper Cretaceous stratigraphy of North Bulgaria. Bulletin of Mos-cow Society of Naturalists, Geological Series 73 (1), 17–28 (in Russian, with English abstract).

Jolkichev, N.A., Naidin, D.P. 1999. The Upper Cretaceous of North Bulgaria, Crimea and Mangyshlak. Article 2. Cre-taceous stratigraphy of South-Western Mountain Crimea. Bulletin of Moscow Society of Naturalists, Geological Se-ries 74 (5), 48–59 (in Russian, with English abstract).

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Jolkichev, N.A., Naidin, D.P. 2000. The Upper Cretaceous of North Bulgaria, Crimea and Mangyshlak. Article 3. Upper Cretaceous stratigraphy of the western part of Mountain Mangyshlak. Bulletin of Moscow Society of Naturalists, Geological Series 75 (6), 62–75 (in Russian, with English abstract).

Jolkichev, N.A. 1999. New data about the age of the Byalo bar-do Formation in its type section. Review of the Bulgarian Geological Society 60 (1–3), 99–101 (in Bulgarian, with English abstract).

Kennedy, W.J., Jolkičev, N. 2004. Middle Cenomanian am-monites from type section of the Sanadinovo Formation of northern Bulgaria. Acta Geologica Polonica 54 (3), 369–380.

Jolkičev, N.A. 2006. The Cretaceous/Paleogene (K/Pg) bound-ary in the Mezdra and Lyutidol syncline, Vratza District (West-Fore Balkan, Bulgaria). Annales Géologique de la Péninsule Balkanique 67, 41–49.

Jolkičev, N.A. 2007. The Cretaceous/Paleogene boundary in the Eastern Fore-Balkan (Luda Kamchia Defile – locality of Chudnite Steni). Review of the Bulgarian Geological So-ciety 68 (1–3), 41–45.

Jolkičev, N.A. 2009. Discussion on the lithological composi-tion and age of the rocks from the core and limbs of the Lyutidol syncline, Western Fore-Balkan. Review of the Bul-garian Geological Society 70 (1–3), 151–164 (in Bulgarian, with English abstract).