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GEOWGICA BALCANICA, 26. 2, Soft&, Jun. 1996, p. 3-10 Geological Heritage of the Balkan Peninsula: Geological setting (an overview) Ivan S. Zagorchev Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Street, build. 24, 1113 Sofia Hs. 3azop'U!6 - reoAOZU'leCJCoe HaCAedcmso EaAKaHc Abstract. The Balkan Peninsula represents a region of KOzO n011yocmp06a: zeOAOZU'U!CKtlJf paMKa (0030p).lian particularly complex geological composition and structure IaHCKRI oonyOCTPOB xaparrepH3yeTCI ~pe3B~~alao that is situated within the boundary between the Eurasian cno:aHWMR reonOrH'IeCDIM COCTaBOM B CTPOeHBeM, ~TO and African plates where the Tethyan Ocean has been o6ycnoBneao ero nono:ateaaeM aa CThfl(e MeQy EBpa- consummed in Alpine times. The geological structure 3Bica:oii a A.Ppaa:aacJtoii DJlhlTaMH r.Ae B am.DBAca:oM represents the setting of many geosites of national, regional BpeMeHB 6w1 a:oacyMMHPoBaa TeTacltBA oa:eaa. Cno:at or world-wide importance. au reonorH~eca:u CTPYITYPa coCTaBnleT P&MitY MHO rex 3neMeHTOB reonora~eca:oro aacne.ACTBa aa~ao aan&soro, perHoaan&aoro H MBpOBoro 3Ha~eau. Zagorchev, I. 1996. Geological Heritage of the Balkan Peninsula: Geological setting (an overview). - Geologica Bale., 26, 2; 3-10. Key words: geological heritage; Balkan Peninsula; geological setting Introduction Heritage of Bulgaria: National Strategy and Sites of Special Scientific Importance" of the National The First Subregional Meeting "Conservation of Fund "Scientific Research" of Bulgaria. the Geological Heritage in South-East Europe" (6 - 12 May 1995; Bulgaria) outlined the Geological Heritage possibilities for establishment of a subregional Balkan Geological Heritage List, as an integral In the broadest sense, the Geological Heritage part of the European and World Geological of a natural or political region consists (Za Heritage Lists. Several contributions have been gorchev, Tzankov, 1996) of its whole geological dedicated to particular geosites or geological wealth, as: 1) mineral occurrences (mineralogical areas of the Balkan Peninsula that represent a features, mineral ore and non-metallic deposits); precious geological heritage of our countries. 2) water sources (mineral, karst, etc.); 3) rocks They are published in the present special issue (petrologic features); 4) fossils; 5) stratigraphic of Geologica Balcanica in accordance with the sections and other stratigraphic features; 6) decisions of the Editorial Board and of the First structural-geological features; 7) complex Subregional Meeting. geological sites; 8) old and/or abandoned The present paper aims to give some essential quarries and mines; 9) unique objects and sites; general information about the most typical 10) geomorphic features; 11) coal and hydro geological features of the Balkan Peninsula carbon deposits; 12) geological information. relevant to the evaluation of our geological According to the classification of the IUGS heritage. The author is indebted to Dr W. Global Geosite Working Group (Anon., 1995), Wimbledon who stimulated this paper as well the geosites that are elements of the World as to many colleagues who supplied precious Geological Heritage belong to the following information and advice. The paper is written Earth Science Categories: A. Palaeobiology; B. within the frame of the project "The Geological Geomorphic; C. Palaeoenvironmental; D. 3 Igneous, metamorphic & sedimentary; E. (north-vergent Carpatho-Balkanides and south Stratigraphic; F. Mineralogic; G. Structural; H. vergent Dinarides - Hellenides) divided Economic; I. Historic; J. Relationships: tectonic (according to different viewpoints exposed) by plates; K.. Astroblemes; L. Continental/Oceanic a central or median massif (Rhodope Mass, global scale features; M. Submarine. Geosites Thracian Massif, Rhodope Massif, etc.) or are also regarded as being important for the central (third) branch of the orogen. The characterization of: I. major stages of Earth structure that divided the two branches was history; II. ongoing geological processes; Ill. sought either in one of the massifs (Serbo geomorphic, physiographic features. The Macedonian, Rhodope, Thracian) or in a suture charact~ristics of the geological sites in respect (Vardar Zone, Maritsa suture, K.raishtid-Vardar to their interest for the specialists and the general Lineament). public favour a most convenient classification The modern tectonic concept is based upon that defines three large groups: geological sites the plate tectonics ideas about the evolution of of economic, commercial or utilitarian value the Tethyan Ocean and of several microplates (GSECV), geotopes (geosites) of special situated between the Eurasian and African scientific importance (GSSSI) and geotopes plates. Drastic changes within this evolution (geosites) of aesthetic value (GAY). The present occurred during several important compressive paper is not concerned with the first category phases in Late Triassic, Late Jurassic, Mid because it is the subject of metallogenetic, Cretaceous, Late Cretaceous, Mid-Eocene, latest economic, hydrogeological and other research. Eocene and earliest Miocene times. Relics of The geological heritage in the narrower sense is Paleozoic and pre-Paleozoic rocks, structures concerned with geological sites remarkable with and terranes are reworked and incorporated into their aesthetic, educational and scientific value. the Alpine structures, and tectonic llnits from Their evaluation is based upon aesthetic value, the older orogens are welded into the younger rarity or uniqueness, access for scientific and ones as an intricate jigsaw puzzle. The picture educational purpose. The geological setting of is even more complicated in Neogene and the Balkan Peninsula is considered here in Quaternary times when prevailing vertical respect of such features of the geological movements in conditions of generalized exten heritage. sion led to block rotations and formation of a The geological sciences study the present 3D neotectonic block pattern. Controversial recon structure of the Earth's crust as a result of the structions are often based more on fashionable long evolution through geologic time. Although ideas than on real evidence. Therefore, key each geological site is in some sense a unique sections and outcrops may be of paramount natural feature, many sites contain common or importance for confirming or rejecting some of comparable features or elements of similarity. the hypotheses, thus representing most valuable Only few of the geosites may be considered as geological heritage. being of outstanding value as the finest The superposition of Alpine orogenic (fold specimens that demonstrate the typical features and thrust) structures issued from different, of their kind. Few others are unique phenomena mostly continental and epicontinental marine that have no similar sites all over the world. This basins resulted in a complicated pattern further paper aims to outline mostly such geological exhumed and modelled by neotectonic move features of the Balkan Peninsula that bear the ments and erosion. Rock complexes of different marks of rarity or uniqueness, and to look for age occur in the Alpine tectonic units, covering geosites that can be regarded as the finest almost the full range from the Precambrian examples of such features. (Middle Riphean or even older) and Paleozoic to the Quaternary. Several different pre-Alpine section types clearly belong to different pre Alpine (Alpidic) structure Hercynian and Hercynian environments, and are covered with unconformable depositional The classical concept about the Alpine structure contact by different Hercynian molasse deposits of the Balkan Peninsula was conceived within of Carboniferous or Permian age, and/or directly the classical frame of the geosynclinal theory in by Alpine sedimentary and volcanic complexes. the nineteenth century by E. Suess, J. Cvijic and The most important pre-Alpine complexes are: other scientists, and further elaborated in the (i) Precambrian amphibolite-facies metamorphic first half of the twentieth century by L. Kober, complexes (Ograzhdenian and Rhodopian F. Kossmat, V. Petkovic, S. Boncev, E. Boncev, Supergroups in Bulgaria, and their equivalents J. Brunn up to the "Geosynclines" of J. Aubouin. in the other Balkan countries - e.g., Ko It recognized the existence (e.g., Mabel' ed., zhoukharov, 1986; Mountrakis, 1986; Zoubek, 1974) of two branches of the Alpine orogen ed., 1988; Papanikolaou, 1989); (ii) Vendian - 4 Cambrian greenschist-facies metamorphic rocks 1982; Papanikolaou, 1983, 1984; Arsovski, tb.at primarily belonged either to ocean Dumurdzhanov, 1984; JacoBshagen, 1986; environments or to island-arc associations with Mountrakis et al., 1987; Boyanov et al., 1989). abundant diabases (e.g., Haydoutov, 1989); (iii) These tectonic regions are (from the North low-grade to greenschist-facies terrigenous to the South): (i) Moesian region (platform); (ii) formations (with some carbonates and silicites) Carpathian mountain range; (iii) Balkan (Stara of Ordovician to Late Devonian age (e.g., Yanev, Planina) Mountain range; (iv) Srednogorie 1994). All three types of pre-Alpine complexes region (including the Maritsa valley); (v) are intruded by Hercynian (and in some cases, Macedonian - Rhodope (Morava-Rhodope) even older) granitoid plutons. region with the Rhodope, Strouma, and Morava The geological structure of the Balkan (=Serbo-Macedonian) subregions; (vi) Vardar Peninsula may be considered within several main region (zone); (vii) Dinaride-Albanide-Hellenide