GEOLO[KI ANALI BALKANSKOGA POLUOSTRVA 67 19–33 BEOGRAD, decembar 2006 ANNALES GÉOLOGIQUES DE LA PÉNINSULE BALKANIQUE BELGRADE, December 2006 Tran-sborder (south-east Serbia/west Bulgaria) correlations of the Jurassic sediments: Infra-Getic Unit 1 2 PLATON TCHOUMATCHENCO , DRAGOMAN RABRENOVI] , 3 4 BARBARA RADULOVI] & VLADAN RADULOVI] Abstract. The Infra-Getic Unit is a palaeogeographic unit, predestined by palaeotectonics. From the point of view of geological heritage, it represents a geosites framework. For the purpose of the correlation, the Serbian sections of Lukanja, Bogorodica Monastery, Rosoma~ and Senokos, as well as the Bulgarian sections of Komshtitsa, Gintsi, and Stanyantsi were used. The Jurassic sediments of the Infra-Getic Unit crop out on the southern slops of the Stara Planina Mountain in east Serbia and west Bulgaria. The Lower Jurassic started with continental and continental-marine sediments (clays and sandstones) (Lukanja clastics and Lukanja coal beds in Serbia and the Tuden Formation in Bulgaria) and continue with Lukanja quartz sandstones (Serbia) and the Kostina Formation (Bulgaria). These sediments are covered by Lukanja brachiopod beds and Lukanja limestones (Serbia) and the Romanov Dol, Ravna and Dolni Loukovit Members of the Ozirovo Formation (Bulgaria) pre- dominantly consist of bioclastic limestones. The sedimentations follow with Lukanja belemnites-gryphaea beds (marls and clayey limestones), which in Bulgaria correspond to the Bukorovtsi Member (also marls and clayey limestones) of the Ozirovo Formation. The Middle Jurassic sedimentation started with black shales with Bossitra alpine. These sediments are individualized in Serbia as Senokos aleurolites and clays and in Bulgaria they are known as the Etropole Formation. In Serbia the section continues with sandstones called Vodeni~ki sandstones of Bajocian age, known in Bulgaria as the Dobrogled Member of the Polaten Formation. However, in Bulgaria, the age is Upper Bajocian–Lower Bathonian, and it cover the marls of the lower member (Gornobelotintsi Member) of the Bov Formation and is covered by the upper member – alternation of marls and clayey lime- stones – the Verenitsa Member of the Bov Formation. The Vodeni~ki sandstones–Dobrogled Member which ended their distribution in the section of Komshtitsa, to the east (in the Gintsi section), they are not represent- ed – build a body of sandstones, a prodelta coming from the west to the east. The Bov Formation corresponds to the Senokos ammonite beds in east Serbia. The upper boundary of the Senokos ammonite beds and of the Bov Formation is sharp. It is covered by grey limestones of the Yavorec Formation in Bulgaria and by the Kamenica limestones in eastern Serbia. They are covered by grey or red nodular/lithoclastic limestones (“ammo- nitico rosso” type) of the Gintsi Formation in Bulgaria and the Pokrovenik ammonitic (acanthicum) limestones in Serbia. The Jurassic section in the Infra-Getic ended with grey micritic and lithoclastic limestones, which belong to the Rosoma~ and Rsovci limestones in east Serbia and to the Glozhene Formation in Bulgaria. Key words: Jurassic, Infra-Getic, correlations, lithostratigraphic units, south-eastern Serbia, western Bulgaria. Apstrakt. Infragetska jedinica je paleotektonski uslovqena paleoeografska jedinica a sa stano- vi{ta geolo{kog nasle|a predstavqa podru~je geolo{kih objekata. U ciqu upore|ewa analizirani su profili Lukawe, Manastira Bogorodice, Rosoma~a i Senokosa u Srbiji i profili Kom{tice, Ginci i Stawanci u Bugarskoj. Jurski sedimenti Infragetske jedinice su otkriveni na ju`nim padinama Stare Planine u isto~noj Srbiji i zapadnoj Bugarskoj. Dowa jura po~iwe sa kontinentalnim i kontinentalno- marinskim sedimentima (glinci i pe{~ari) (Lukawski klastiti i lukawski slojevi ugqa u Srbiji 1 Geological Institute, Bulgarian Academy of Science, Acad. G. Bonchev str. Bl. 24, 1113 Sofia, Bulgaria. E-mail: [email protected]. 2 Department of Geology, Faculty of Mining and Geology, University of Belgrade, Kameni~ka 6, 11000 Belgrade, Serbia. 3 Natural History Museum, Njego{eva 51, 11000 Belgrade, Serbia. E-mail: [email protected]; [email protected] 4 Department of Palaeontology, Faculty of Mining and Geology, University of Belgrade, Kameni~ka 6, 11000 Belgrade, Serbia. E-mail: [email protected] 20 PLATON TCHOUMATCHENCO, DRAGOMAN RABRENOVI], BARBARA RADULOVI] & VLADAN RADULOVI] i Tuden formacija u Bugarskoj) i nastavqa se Lukawskim kvarcnim pe{~arima (Srbija) i Kostinom for- macijom (Bugarska). Ovi sedimenti su prekriveni Lukawskim brahiopodskim slojevima i Lukawskim kre~wacima (Srbija) i ~lanovima Romanov Dol, Ravna i Dolni Lukovit Ozirovske formacije (Bugarska) iygra|eni prete`no od bioklasti~nih kre~waka. Sedimentacija se nastavqa Lukawskim belemnitsko- grifejskim slojevima (laporci i glinoviti pe{~ari) kojima u Bugarskoj odgovara Bukurova~ki ~lan (tako|e laporci i glinoviti pe{~ari) Ozirovske formacije. Sredwojurska sedimentacija po~iwe crnim glincima sa Bossitra alpina, sedimentima koji su u Srbiji poznati kao Senokoski alevroliti i gline, a u Bugarskoj kao Etropolska formacija. U Srbiji se profil nastavqa Vodeni~kim pe{~arima bajeske starosti, koji su u Bugarskoj poznati kao Dobrogledski ~lan Polatenske formacije gde su gorwo- bajeske–dowobatske starosti. Ovi pe{~ari prekrivaju laporce ~lana Bov formacije (Gorwobelotina~ki ~lan), a preko wih le`i gorwi ~lan iste formacije (Vereni~ki ~lan) izgra|en od smene laporaca i gli- novitih kre~waka. Vodeni~ki pe{~ari, odnosno Dobrogledski ~lan, zavr{ava se u profilu Kom{tice, daqe prema istoku (u profilu Ginci) oni nisu razvijeni. Bovska formacija odgovara Senokosnim amonit- skim slojevima u isto~noj Srbiji. Gorwa granica Senokosnih amonitskih slojeva i Bovske formacije je o{tra; prekrivena je sivim kre~wacima Javore~ke formacije u Bugarskoj, odnosno Kameni~kim kre~waci- ma u isto~noj Srbiji. Preko wih le`e sivi i crveni kvrgavi ili litoklasti~ni kre~waci (tipa ammoniti- co rosso) Ginci formacije u Bugarskoj i Pokroveni~ki akanti~ki kre~waci u isto~noj Srbiji. Jurski pro- fil u Infra-genetikumu zavr{ava se sivim mikritskim i litoklasti~nim kre~wacima Rosoma~a i Rsovaca u isto~noj Srbiji i Glo`enskoj formaciji u Bugarskoj. Kqu~ne re~i: Jura, Infra-getik, upore|ewe, litostratigrafske jedinice, jugoisto~na Srbija, zapad- na Bugarska. Introduction mid conditions. In Bulgaria, the Komshtitsa Formation, after TRONKOV (1993, p. 170) is connected by a progres- In this paper we expose our essay to make correla- sive lithologic passage with the Carnian Russinovdol tions accross the Serbian/Bulgarian state border of the Formation and for that reason it is considered as existing in the published literature Jurassic formal litho- Carnian–Norian. stratigraphic units in the framework of the Infra-Getic In the section of Velika Lukanja, the Jurassic sub- paleotectonic and paleogeographic unit (Fig. 1). This stratum is represented by 2 m of thick red breccia lime- unit is known in the Serbian literature presumably as stones – the Jelovica limestones (Pl. 1, Fig. 1), of Late the Staroplaninska–Pore~ka units (ANDJELKOVI] et al., Raetian age (ANDJELKOVI] et al., 1996, p. 78). 1996) and as the Izdremets Jurassic paleograben (SAPU- In the out crops near the villages Stanyantsi, NOV et al., 1986, etc.). Berende Izvor, Tuden, etc. in Bulgaria, the Jurassic substratum is built up of grey Middle Triassic lime- stones of the Iskar Carbonate Group. Substratum The substratum of the Jurassic sediments in the stud- Lower Jurassic (Figs. 2, 3) ied area of the Infra (Sub)-Getic consists of Triassic rocks. In the Serbian Bogorodica, Rosoma~ and Senokos In the vicinities of the villages of Velika Lukanja sections, the substratum consists of redish aleurolites, (Serbia) and Stanyantsi (Bulgaria), the Lower Jurassic marls to argillites with concretions of sphaero-siderites, sedimentation started by a continental sedimentation (Fig. inter-bedded by sandstones, from 5 up to 100 m thick. 2). These sediments are called, in Serbia, the Lukanja They are called the Senokos red series (ANDJELKOVI], clastics and Lukanja coal beds (ANDJELKOVI], 1996, p. 1996, p. 78) (Pl. 1, Fig. 2). These sediments cross the 84–86) and, in Bulgaria, the Tuden Formation (SAPUNOV state border near the village Komshtitsa and continue to et al., 1990). They are covered by marine sandstones. the east up to the Gintsi village. They are the Bulgaria The Lukanja clastics, (2–120 m thick), (known also Komshtitsa Formation in the Bulgaria (TRONKOV, 1969). as „podinski nivo”, ANDJELKOVI], 1958, pp. 13–14) lie The problem of the age is controversial because of the with discordance on different Triassic rocks. The lack of characteristic fossils: in Serbia two opinions Lukanja clastics are built up of conglomerates and exist: (1) that of ANDJELKOVI] et al. (1996, p. 78, etc.), sandstones. The conglomerates are with quartz pebbles after which the Senokos red series is with the Late and cement of silica, rarely of clay. The sandstones Triassic age; (2) this of URO[EVI] & RADULOVI] (1990), predominantly consist of quartz and silica or clayey after which they are Rhaeto–Liassic. ANDJELKOVI] (1996, cement. (Pl. 1, Fig. 4). p. 78) considered the Senokos Formation as Upper Rhae- The Lukanja coal beds (8–150 m thick) started with tian because they were formed under a dry and hot cli- fine grained quartz sandstones are gradually intercalated by mate, while Jurassic sediments were formed under hu- clay and clayey sandstones with coal beds (Pl. 1, Fig. 3). Trans-border (south-east Serbia/west