GEOLOGICA BALCANICA, 30, 3-4, Sofia, Febr. 2001, p. 59-63

New fossil evidence for the Lower Paleogene ( Krumovgrad Group) in the East , SE

Ek. Dimitrova, A. Goranov, Iv. Boyanov

Geological Institute, BAS, 1113 Sofia; E-mail: [email protected] (Submitted 15.12.1999; accepted for publication 23. 06.2000)

EK. /{uMumposa, A. ropaH08, Hs. bO.RH08. HOBble na­ Abstract. Ek. Dimitrova, A. Goranov, Iv. Boyanov. New JieOHmOJIOZU'IeCKUe daHHble 0 paHHeM naAeozeHe (Kpy­ fossil evidence for the Lower Paleogene (Krumovgrad MOBZpadcKa.R zpynna) s Bocmo'IHblX Podonax. OpraHo­ Group) in the East Rhodope Mountains, SE Bulgaria. An reHHbte H3BeCTHJIKH cpe~H rpy6oTeppHreHHLIX OTROliCe­ Algal detritus which is the basic rock-forming material is HHH Kp}'MoBrpa~cKoH rpynn1.1 K10ry oT r. Huai{nourpa­ established in the organogeneous limestones among the lla no p. KocTHnKOBCKOH (MaH~PHUCKoe noHHliCeHHe) coarse-terrigenous deposits of the Krumovgrad Group of cnoliCeHbl npeHM}'lllecTBeHHO BO!lopacneBbiM ~eTpHry ­ the Mandritsa depression to the South of lvaylovgrad coM. B HHX ycTaHOBneHo IIJopaMHHHIIJepouoe coo6tQecT­ along the Kostilkovska river valley. A various foraminifer­ so, COCTOllnt.eeCJI rnaBHbiM 06pa30M H3 npe~CTaBHTeneH al assemblage is found in these rocks consisting mainly of ceMeHcTB Lagenidae, Discorbidae, Miliolidae, Textularii­ the representatives of the families of Lagenidae, Discor­ dae, Rotaliidae, Acervulinidae, Linderinidae. bidae, Miliolidae, Textulariidae, Rotaliidae, Acervulin­ 3Ta opraHHJMOBall accouHaUHll xapanepHa ~ll pH­ idae, Linderinidae. These bioassociations are typical of IIJouoii (MenKOBO~HoH) IIJaUHH. B HeH co~epliCaTcll 6onb­ the reef(marine shallow-depth) facies. They contain most WHHCTBO 6H03ReMeHTOB, npHHa~eliCamHX K C006tQeCT­ of the bioelements of the co-assemblages of the intraplat­ BaM BHYTpennaTIIJopMeHHOH IIJaUHH naneoueHOBLIX H form facies of the Paleocene and the Early up to Middle paHHe-cpe!lHe3oUeHOBLIX 6acceHHOB JOliCHoro TeTHca. Eocene basins of the South Tethys. Furthermore, they are KpoMe Toro oRa aHanorH'fHa accouHaUHRM, onHcaHHl>IM analogous to the assemblages described in the Upper Pa­ B uepxHenaneoueHOBLIX ocallO'IHl>IX nopo!lax 3anallHLIX leocene of the West Carpathians and the Middle and Up­ KapnaT H B uepxHeM naneoueHe ,nKHapH~. per Paleocene in the Dinarides. Following these compar­ Ha OCHOBaHHH 3THX KOppenliUHH pa3pe3bl rpy6oKnaC­ isons, the age of the coarse-clastic deposits along the Ko­ TH'IeCKHX nopo~ p. KocTHnKOBCKOH B MaH~PHUCKOM no­ stilkovo river valley could be referred to the span Upper HHliCeHHH OTHeCeHbl K ~HanaJOHY, KOTOpbiH OXBaTl>IBaeT Paleocene - Middle Eocene. Thus, the presence of marine sepxHHH naneoueH - cpe~HHH 30UeH. TaKHM o6pa3oM Lower Paleogene sediments is proven also in the West npHCYTCTBHe MOpCKOrO paHHero naneoreHa ~OKaJaHO H part of the East Thracian depression. !lnll Jana~HOH qacTH BocTO'IHoiiJpaKHHCKOH ~enpeccHH.

Dimitrova, Ek., Goranov, A., Boyanov, lv. 2000. New fossil evidence for the Lower Paleogene (Kru­ movgrad Group) in the East Rhodope Mountains, SE Bulgaria - Geologica Bale., 20, 3-4; 59-63 Key words: SE Bulgaria, East Rhodope Mountains, Krumovgrad Group, Lower Paleogene, fossil evidence.

Introduction anov and Goranov (1994) published a generali­ zation about the presence of the Late Paleo­ Finding of the Paleocene in Krumovgrad gene deposits in the East Rhodope Moun­ area, East Rhodope Mountains (Atanasov, tains and described for the first time the pres­ Goranov, 1984) led to intensive investigations ence of marine Paleocene - Eocene sediments which proved the presence of that system proven by pelagic microfauna in the Asen­ in many more places in the same region. Boy- ovgrad area.

59 Geological background rocks which are various in respect to composi­ and faunistic data tion and sizes. There are a sand-conglomerate bands into the Lower Paleogene depositions as The present paper reports new faunistic infor­ well as organogenous limestones lenses with mation about the sediments of the Kru­ thickness from 0,6 up to 7-8 m that contain a movgrad Group (Goranov, Atanasov, 1992). big amount of terrigeneous components. These They fill in the South margin of the Mandritsa biodetrital limestones are exposed in the Kos­ depression located to the South of tilkovo river valley and along the ridge near by along the Kostilkovska river valley and to the Petrova Mogila peak (fig. 1). North of Petrova Mogila peak in the areas of The limestones are composed mainly by algae, Kostilkovo, Oreshino, Mandritsa, Dolno Luk­ bryozoans, corales and microfossil detritus. A rel­ ovo and Meden Bukvillages (fig. 1). In respect atively diverse foraminiferal association of repre­ of geotectonics that depression builds up the sentatives of the families Lagenidae, Discorbidae, westernmost periphery of the wide East Thra­ Miliolidae, Textulariidae, Rotaliidae, Acervulin­ cian depression developed widely on the terri­ idae and Linderinidae was established. Sections of tory of and Turkey where a presence of Rotalia sp., Pyrgo sp., Eoanularia cf. eocenica a marine type of Paleocene is proven (Suemen­ Cole & Bermudez, Sphaerogypsina cf globulus gen, Terlemez, 1991). The Krumovgrad Group (Reuss), Eofabiania cf grahami Kueper, Planor­ is undifferentiated in the range of the Mandrit­ bulina sp. (Table I, II) were determined. The strati­ sa depression. It is mainly represented by boul­ graphic distribution of the last four species is con­ der-block, poligenic breccia consisting of olis­ sidered as Paleocene - Eocene up to Holocene tolites and olistoplacas of high-grade meta­ (Loeblich, Tappan, 1988). morphic and low-metamorphic Phanerozoic The main rock-forming organogenous com-

...... 0 - """ - "'" ...... ------0 0 - 0 0,5 1km

Fig. l . Geological map of the Paleogene, (Krumovgrad Group) in lvaylovgrad area, East Rhodope Mountains l - Mezozoic low-crystalline fundament; 2 - Paleocene- Middle Eocene, Krumovgrad Group; 3 - Upper Eocene, conglomerates, sandstones, limestones; 4 - Fault; 5 - transgresive boundary; 6 - Fauna sample number

60 ~ °Komouniga ,. ., ,... . ·- - . J / ITIJ1 Ds­ EEB2 G6 1,.....,-,7 I ( -3 / ~8 0 DZHEBEL -~ ' ' \ !~' (OSOFIA {

. ~ · , \.- ·- ., . . . . ,. .... '

· \..· 0 4 8 12km

Fig. 2. Scheme of the Lower Paleogene depositions distribution in the East part of the Rhodope Mountains area Pre-Paleogene fundament: l - Rhodope super unit; 2 - Sredna Gora super unit. Paleocene - Middle Eocene (Krumovgrad Group); 3 - Continental fresh water depositions; 4 - Marine depositions; 5 - Paleogene - Neogene sediment cover; 6 - Geological boundary; 7 - Faults; 8 - Reverse-slip faults and overthrusts 0\ PLATE I

1. Nummulites sp., sample 2255, Topolovo Formation, Paleocene ; x60. 2. Eofabiania cf. grahami Kueper, sample 94/21", Kostilkovska River, Paleocene - Middle Eocene; x60. 3. Planorbulina sp., sample 94/65, Kostilkovska River, Upper Paleocene - Eocene; x70. 4. Miliolidae, ?Peneroplidae, Rotaliidae (Rotalia sp.), Algae, sample 94/65, Kostilkovska River, Paleocene; x60. 5. Miliolidae, Linderinidae (part), sample 94/65a, Kostilkovska River, Paleocene - Eocene; x60. 6. Miliolidae, (Pyrgo sp.), Algae, sample 94/65a, Kostlkovska River, Paleocene- Eocene; x60.

PLATE II

Mandritsa Regoin, Krumovgrad Group

1,2. Eoanularia sp. (in the association on the fig. 2: Lagenidae and Anomalinidae), sample 94/67, NW Petrova Mogila Pike, Eocene; x80. 3. Sphaerogipsina cf. globulus (Reuss), sample 94/67, NW Petrova Mogila Pike, Eocene; xSO. 4, 4a.Remanellina cf. eocenica Tappan & Loeblich, sample 94/67, NW Petrova Mogila Pike, Eocene, XSO; fig. 4ax120. 5. Eoanularia sp. , sample 94/64, N Petrova Mogila Pike, Eocene;x60. 6. Algae (Distichoplax cf. biserialis Dietrich), sample 94/64, N Petrova Mogila Pike, Eocene;x80.

PLATE Ill

Topolovo Formation l. Heterohelicidae (Chiloguembelina), Globigerinidae, ? Bolivina sp., sample 2255, Paleocene; x80. 2. Globigerinidae, sample 2255, Paleocene; XSO. 3. Globoconusa daubjergensis (Bronnimann), sample 2254, Paleocene; x80. 4. Globigerinidae (Globigerina gr. triloculinoides Plummer), sample 2257, Paleocene; x80. 5. Globigerinidae, sample 2259; x80. 6. Globigerinidae, ?Globigerinella sp., sample 2257, Paleocene; x80.

62 PLATE I

Ek. Dimitrova, A. Goranov, Iv. Boyanov, Geologica Balcanica, 3-4/2000 PLATE II PLATE III ponents are the algae and some of them are de­ Conclusions termined as Distichop/ax biserialis Dietrich and Peyssonella antiqua Johnson (pl. I, fig. 6; pll. The comparisons performed in this paper allow fig. 6). They are widely represented in the Pa­ the coarse-clastic depositions of the area along leogene biofacies (AGIP, Atlas, 1988; Samuel the Kostilkovska river valley, Mandritsa subsid­ et al., 1972). A section of calpionelides was ence, to be referred in respect of their age to the found, tappanstoeblich and determined as - age span Late Eocene- Middle Eocene. In that Remanel/ina cf. eocenica (pl. II, fig. 4, 4a). way for the first time a marine Lower Paleogene The available fossil material is badly pre­ presence is proven in the western part of the served and is often strongly recrystallized. The East Thracian depression. non-characteristic foraminiferal sections do not allow a more exact species determination. Most of the cited taxa appear in the Late Pale­ References ocene and attain a wide occurrence during the Middle Eocene. The associations determined in AGIP. 1988. Southern Tethys Biofacies.- San Donato Milanesae, 235 the region are characteristic for marine shal­ Atanasov, G., Goranov, A. 1984. On the paleogeography of low-depth (reef) facies and as a whole are anal­ the Eastern Rhodopes.- C. R. A cad bulg. Sci, 37, 6; 783-784. ogous to that ones described for the Upper Pa­ Eames, F., Banner, F., Blow, W., Clarce, W., Smout. A. 1962. leocene of the West Carpathians (Samuel et al., Morphology taxonomy and stratigraphic occurrence of 1972) and for the Middle and Upper Paleocene the Lepidocyclinidae. - Micropaleontology, 8, 3, 289- 322. Goranov, A., Atanasov, G . 1992. Lithostratigraphy and of the Dinarides (Radoicic, 1960). Those asso­ formation conditions of Maastrichtian - Paleocene in ciations consist most of the typical bioelements Krumovgrad District. -Geologica Bale., 22, 3; 71 - 82. of the intraplatform facies assemblages if the Kalantari, A. 1995. The Paleocene - Lower Eocene Paleocene and Early-Middle Eocene basins of boundary in the type sections of the K.huzestan and the South Tethys. (AGIP - Atlas, 1988; Salay, Lurastan areas (SW Iran).-Neues Jb. Geol. Paleont. Abh., 198, 3; 375-387. Maamouri, 1988). Loeblich, A. Jr., Tappan, H. 1988. Foraminiferal Genera For a difference of the limestones in the inves­ and their Classification. New York Van Nostrand tigated area the limestones of the Northern mar­ Company; 970 p. gin of the East Rhodope Mountains depressions Radoicic, R. 1960. Microfacies du Cretace et du Paleo­ (the area of the village of Topolovo) associating gene des Dinarides externes de Jugoslavie. lnst. Rech. with Early Paleogene coarse-terrigenous sedi­ Geol. de P. R. Cerna Gora. Paleont. des Dinarides Jugosl., A, Micro- pal., 4,1; 172 p. ments have a pelagic character (Boyanov, Gora­ Salaj, J., Maamouri, Annie-Louise. 1998. Atlas of Tuni­ nov, 1994). A foraminiferal planctonic associa­ sian Microbiofacies and its Relation to some Circum tion was found in them: Globigerinidae, Globoco­ Tethydian Types, part IV. Zemny Plyn a Nafta, 43,4. nusa daubjergensis (Bronnimann), G/obigerina gr. Samuel, 0 ., Borza, K., Koehler, E. 1972. Microfauna and Lithostratigraphy of the Paleogene of the Middle Van triloculinoides Ftummer, G/obigerinella sp. Valley (West Carpathians) Geol. Ustav. Dionyza Stura, Heterohelicidae (Chiloguembelina sp.). It indi­ Bratislava; 246 p . cates also a Paleocene - Middle Eocene age, and Suemengen, M ., Terlemez, I. 1991. Stratigraphy of a relatively deeper marine conditions of sedimen­ eocene sediments in the South-West . Mineral tation. Rez. Exsp. Bull., 113; 15-29. DOJIHOB, H., ropaHOB, A. 1994. lla.neonen-eoneHCICH ce­ The Lower Paleogene deposition distribution ,nHMeHTH oT ceaepnan nepncllepHR na l>opoBHWJCaTa in the east part of the Rhodope Mountains area .nenpecHR H Kopenanuua HM c no.no6HH ce.nnMeHTH B is shown in fig. 2 where the marine and conti­ H3TO'fHOpo.noncKOTO naneorencxo noHH)J(eHHe. - Cn. nental sediments are separated. EMz. zeoA. iJ-eo, 55, 1; 83-102.

63