GEOLOGICA BALCANICA. 26. 2, Sofia, Jun. 1996, p. 63-80

Tectonic Sites of Special Scientific Importance (TSSSI) in tbe Mid -Cretaceous Strouma Superunit, Southwest Bulgaria

Jl·an S. Zagorchev

Geologica/Institute, Bulgarian Academy of Sciences, Acad G.Bonche~ St. build. 24. 11/3 Sofw. Bulgaria

Ja~op'U!e- Te~emOHU'4eCICUe o6&eiC111bl cne&~UaAbHO ­ Abstract. The Mid-Cretaceous tectonic structure of ~ IUJY~Utozo 3Ha'4eHwr e cpedHeMeAoeou CmpyMciCou Southwest Bulgaria consists of the parautochthonous ~.JOzo-JanadHa.Ji E011zapwr. Cpe.llHeMenoaoe Te&­ Strouma Superunit and the allochthonous Morava ecaoe CTJ)OCHHe 10r0-3808,1lHOI Jio.nrapHH COCTO­ Superunit. Five sections represent excellent exposures of :U 10 napaaTOXTOHHol Crp)'Mcaoll e.llBRHilW H aJIJIOX- unique tectonic features. They should be protected by the A Mopaacaol e.llHHHUbl. IbTb p83peJoB BbiJIBnll- State, and conserved in a manner suitable for preservation 11:7 )'Blll:&nbHble TeKTORH'IeCa:He OC06tHHOCTH. 0HH as well as for educational and scientific purposes . .JOID"Hbl 6b1Tb DOCT&BneHbl DO.ll JllU.lHTOA rocy.llapcna, • cepsHpOBaHiol Taa:HM cnoco6oM 'ITOObl o6ecne'tHTb toXpaHeHlle .11M H8}"1HWX Hccne,nOBaHHA H ,lleMOHCT­ C yqe6Hol uenbiO. b:gorchev, I. - Tectonic Sites of Special Scientific Importance (TSSSI) in the Mid-Cretaceous uma Superunit, Southwest Bulgaria. - Geologica Bale., 26, 2; 63-80.

~· words: geological heritage; Southwest Bulgaria; tectonic sites

Introduction Geological setting present paper aims to draw the attention Strouma Superunit ds five geological sites that should be "dered as Sites of Special Scientific The Strouma Superunit (Strumicum; Trun­ portance (SSSI) and placed under the VIahina structural zone - Zagorchev, 1984, ection of the State. They have a complex 1990) is a parautochthonous element (Fig. I) of mostly tectonic character, and exhibit the Mid-Cretaceous ("Austrian") structure of rtant relations between different geological Bulgaria that has been included in the Late ·es being also (in some cases) stratotypes of Cretaceous Morava-Rhodope structural zone al lithostratigraphic units. These sites are (Boyanov et al., 1989). After the main Mid­ tg. 1): I. Road cut south of the village of Cretaceous folding, the formations of the .urvodol; 2. Road cut near the village of Superunit have been covered in Mid-Cretaceous Gurbino; 3. Road cut west of the village of time by the thrust sheets of the Morava yantsi; 4. Ravine near the village ofPoletintsi, Superunit, and furthermore, folded together in confluent of the river Poletinski-dol; 5. Road Late Cretaceous time, and covered (sealed) by near the village of Tsurvishte. Paleogene sedimentary and volcano-sedimen­ These sites should certainly be included in tary formations. · e Bulgarian Geological Heritage List (Bulg The pre-Permian basement of the Strouma (jlfl.) and the Balkan GHL. Some of them may Superunit is of Vlahina type. It is built up of considered as candidates for the European biotite and two-mica gneisses and migmatites GHL, and even for the World GHL. interlayered by amphibolites and quartzo-

63 i~- · ~- .1,...... -., j _l ,. ....- ·

Fig. 1. Sketch map for the position of the tectonic SSSI in the Strouma Superunit. 1 -Alpine plutons; 2- Hercynian granitoid plutons; 3- 5 - southern part of the Srednogorie Superunit: 3 - Melovete (MU) and Radomir (RU) units, 4 - Lyubash and Golo-Burdo units, 5 - Viskyar-Vitosha part; 6 - Louzhnitsa-Trun Unit of the Strouma Superunit; 7 - Osogovo-Vlahina Unit of the Strouma Superunit; 8 - diabase-phyllitoid complexes (mainly Frolosb Formation) of the pre-Alpine basement; 9- Rhodopian Supergroup from the Pirin Unit; 10 - Rhodopian Supergroup of the West-Rita Unit; 11- Ograzhdenian Supergroup from the ~, Kapatnik Unit; 12- Osogovo Formation of the Osogovo l£:3z Subunit, Osogovo-Vlahina Unit; 13 - 14 - Morava Superunit: 13-external thrust units with Paleozoic section ~3 [q:@~f), ~II of Kouchay type (SK- Strumolska klippe, VK- Vlashki­ ~' ~. ~12 ,,.:-, 15 kamak klippe, RN - Rizovtsi thrust sheet), 14- internal thrust units with high-grade metamorphic formations; 15 ~s !lmmg§3r3~r5 - Poletintsi-Skrino fold-thrust zone; 16 -thrusts (a) and ~6 ~.,E:J" ,TS 11 faults (b); 17- tectonic SSSI: SR- section Rayantsi, GT 0 5 1P 15 20km - Gurbino thrust, SP - Section Poletinski-dol, MA­ Murvodol anticlinaloid, TS - Tsurvishte thrust feldspathic gneisses. They are referred to the of the Petrohan Terrigenous Group. The next Precambrian Ograzhdenian Supergroup. This lskur Carbonate Group (Tronkov, 1983) covers amphibolite-facies basement is covered with a the interval from the Spathian (uppermost Lower primary depositional contact (primary uncon­ Triassic) to the Norian, and consists mainly of formity later reworked both tectonically and limestones and dolomites with local marly and metamorphically) by the so-called diabase­ shaly interbeds. The Moesian Group (Norian) phyllitoid complex (Frolosh Formation) built up is represented by marine red beds : shales with of metadiabases, green rocks, actinolite and infrequent limestone interbeds (with Norian chlorite schists, metakeratophyres, etc. that foraminifers) and irregular bodies of underwent a greenschist-facies metamorphism. conglomerates built up predominantly by The rocks of the Frolosh Formation are intruded pebbles of Triassic limestones and dolomites. by the rocks of the Strouma diorite formation, Jurassic formations occur only in the northern with a probable early Paleozoic age. parts (Louzhnitsa- Trun Unit) of the Strouma Permian red beds of the Skrino and Eroul Superunit, to the North of the Poletintsi - Formations (Zagorchev, 1980, 1995) cover with Skrino fold-thrust zone. The usual development unconformable depositional contact all pre­ (Sapunov et al., 1983, 1985; Dodekova et al., Permian rocks and formations listed. The basal 1984) consists of a continental Zhablyano conglomerates contain pebbles of the pre­ Formation (shales, oligomictic quartz sand­ Permian rocks. The thickness is irregular. In stones, conglomerates, with interbeds of black some parts of the superunit, the Permian coal) of Lower Pliensbachian age, followed by deposits are lacking most probably due to the marine Ozirovo Formation (sandy biodetrital primary causes (non-deposition), and the pre­ limestones and calcareous sandstones; Permian basement is covered directly by the Pliensbachian - Lower Toarcian), Gradets basal conglomerates of the Lower Triassic. The Formation (oligomictic quartz sandstones; Lower Triassic is represented mostly by red beds Upper Toarcian -Bajocian), Polaten Formation

64 (biodetrital and oolithic limestones; Aalenian - greenschtst-facies metamorphism; intruding pre­ Lower Bathonian), Yavorets Formation (micritic Permian basic and granitoid rocks; ii) Vlasina and biodetrital limestones with flint nodules; type: amphibolite-facies metamorphic rocks of Middle Callovian - Oxfordian), Gintsi the Dragoychintsi Formation covered by Formation (nodular limestones, often of the metapsammites, metapelites, marbles and "ammonitico rosso" type; Lower Oxfordian - metaphosphorites (Cheshlyantsi Formation) of Lower Kimmeridgian), Neshkovtsi Formation Ordovician age; and iii) Eleshnitsa type: (calcareous shales and marls with some Precambrian? amphibolite-facies metamorphic limestones and sandstones) and Kostel For­ rocks covered by metadiabases, metatuffs and mation (coarse flysch in transition to sandy metaterrigeneous rocks (Zhdrapanitsa Forma­ flysch). The section is ending with a calcareous tion) of Vendian - Early Paleozoic age, and post-flysch with Lower to Middle Berriasian age. graphite-bearing micaschists, quartzous schists, A specific development in a part of the superunit quartzites and limestones (Ruzhcha Formation) is represented by limestone breccia and with recently proven Silurian to Early Devonian conglomerate and micritic limestone (Lobosh age. Formation) in lateral interfingering with the The rocks of the Morava Superunit repre­ limestones of the Y avorets and Gintsi sented the basement of an Early Alpine (Triassic Formations. -Jurassic to Early Cretaceous?) sedimentation Another and very specific Jurassic section zone that possibly was a part of the continental (Treklyano Group) crops out only in the slope towards the Vardar ocean or a very deep westernmost parts of the Louzhnitsa-Trun Unit, gulf of that ocean (Zagorchev, 1986). It has been beneath the thrust sheets (Penkyovtsi and folded and thrusted to the north-east over the Poletintsi thrusts) of the Morava Superunit. The folded Strouma Superunit in Mid-Cretaceous Treklyano Group consists of polymictic time. conglomerates, olistostromes and sandstones (at the base) and interbedding of slates and Murvodol anticlinaloid (MA) radiolarites. Laterally they pass into a shaly formation with sandstone and limestone The Murvodol anticlinaloid (Figs. 2 - 7) is a interbeds. The beds of the Treklyano Group striking example of antiformal syncline cover with depositional contact and (anticlinaloid). It is situated South of the village unconformity the Norian red beds (Komshtitsa of Murvodol, the core cropping out in the stream Formation), and are covered by the flysch of and its eastern bank. The southern limb of the the Kostel Formation. structure is well exposed along the country-road The whole Mesozoic section of the Strouma towards the hamlet Vodenicharska-mahala of Superunit has been folded in Mid -Cretaceous the village of Pastouh, and is covered near that time, and different levels of the eroded section hamlet by the thrust sheet of the Skrino thrust built are covered by the thrust sheets of the Morava up of diorites of the Strouma diorite formation. Superunit. The structure is sealed by a The Murvodol anticlinaloid was discovered neoautochthone of Paleogene (Upper Eocene during the geological mapping on the scale -Lower Oligocene) age. 1:25 000 (Zagorchev, 1968). The deformations, total strain included, are studied in detail Morava Superunit (Zagorchev et al., 1976, 1979; Zagorchev, 1980, 1981). The normal section consists of the The Morava Superunit (Balkan Moravicum - following lithostratigraphic units (Zagorchev, Zagorchev, 1984) is built up (Fig. 1) exclusively 1980, 1995): (at least, on Bulgarian territory) by Paleozoic - Mogila Formation (more than 50 m): dark­ formations alien to the pre-Alpine basement of grey to brownish limestones, with abundant the Strouma Superunit. Three types of Paleozoic calcite veinlets; Spathian - Anisian sections (Zagorchev, 1990a) are exposed in the - Svidol Formation (5 - 8 m): interbedding different thrust sheets (tectonic units) of the of reddish and yellowish sandstones and marls superunit, and namely: i) Kuchay type: diabase­ with yellowish and greyish limestones; Spathian; phyllitoid complex (Buzovitsa Formation) of - Kalenitsa Member of the Murvodol Vendian? - Early Paleozoic age, covered by a Formation (exposed thickness 107 m, pre­ full marine sequence of Ordovician, Silurian deformational thickness of the order of 130 m): (graptolite-bearing shaly complex) and Devonian red polymictic siltstones and sandstones (Vrabcha, Zdravkovi and Staychovtsi For­ interbedded with layers (up to 9 m thick) of mations) rocks, ending with the Upper Devonian quartz oligomictic sandstones; Lower Triassic; - Lower Carboniferous flysch (Melna or - Boyna-chouka Member of the Murvodol Trunovdol Formation); very low-grade to Formation (about 100 m): oligomictic quartz

9 65 I l1 ~2 I. IJ ~~ llllllls~6 ,.-/ 7 ~~8 ~9

o._...... _....,1 _ _.. --*km

Fig. 2. Structural map of the eastern part of the Poletintsi-Skrino fold-thrust zone (after Zagorchev, 1981, Fig. 3).1- Paleogene; 2- Iskur Carbonate Group (Spathian -Upper Triassic), 3 -red beds (sandstones, siltstones, slates) of the Skrino Formation (Permian) and Kalenitsa Member of the Murvodol Formation (Lower Triassic); 4- Boyna-chouka Member (quartz oligomictic conglomerate and sandstone, Lower Triassic) of the Murvodol Formation; 5- pre-Alpine basement; 6- thrust; 7- faults (mainly Late Alpine); 8- slaty cleavage with position of the X axis of the principal strain; 9 -boundaries of intraformational detachment. Position of the Murvodol anticlinaloid (MV) and the Tsurvishte thrust (TS) sandstones with separate quartz and quartzite Vlashkidol Member, and pockets filled in by the pebbles, with oligomictic conglomerate (built up conglomerates of the Boyna -chouka Member of quartz and quartzite pebbles, with rare pebbles - Vlashkidol Member of the Skrino For­ from gneisses, lydites and red polymictic mation (exposed thickness about 30 - 35 m; sandstones) at the base; Lower Triassic; - pre-deformational thickness up to 50 m): light­ overturned depositional contact with a slight red polymictic sandstones; Upper? Permian angular unconformity (well visible in the side - Vodenicharski Member of the Skrino confluent of the river) and partial wash-out, with Formation (about 230 - 250 m; initial pre­ irregular surface of the washed rocks of the deformational thickness about 450 - 500 m): 66 Fig. 3. Geological map of the Murvodol anticlinaloid (after Zagorchev, 1980, Fig. 3) with position (AB) of the section (Fig. 4) and of the overturned contact between the Murvodol and Skrino fonnations (C). I-Paleogene cover, 2 - Islrur Carbonate Group; 3 - Svidol Formation (Spatbian); 4 - K.alenitsa Member; 5 - Boyna-chouka Member; 6- Vlasbki-dol Member; 7- Vodenicharska Member; 8- basement (Strouma diorites), 9-geological boundary (a - unconfonnable, b - normal depositional), 10- thrust (a), fault (b); II -overturned bedding

Fig. 4. Detailed cross section through the Murvodol anticlinaloid (after Zagorchev, 1980, Fig. 4). I- Strouma diorites; 2 -conglomerate; 3 - sandstone; 4 - slate, 5 - siltstone and slate with cleavage traces; 6- limestone and dolomite interlayers; 7 - marls, limestones and shales; 8 ~1 ~2~J l!'_l ~/krz:Js [:),·y·;;: : l6 - limestones; 9 - strain ellipse with bedding S0 and slaty cleavage Sl 1:-:-:I?OJTh .>'tS"",.-1;'9~~1o .A-so 11

S k r i n o Forma iQn

NNE

~@ 900 '" 1000

interbedding of red to purple polymictic - Tsurnirid Sandstone Member (30 - 150 siltstones, shales and sandstones, with carbonate m): polymictic and arkosic sandstones with few concretions and numerous reduction spots; few conglomerate interbeds; Permian?; dolomitic interbeds; Upper? Permian - Tishanovo Conglomerate Member (5 - 30 - lower boundary: unexposed (thrust); m): polymictic conglomerate built up mostly of normally beneath the Vodenicharski Member metadiabase, phyllite, diorite, and granite the section consists of: pebbles, with few sandstone interbeds; Permian? 67 =~ "':._-_ -_ -_-- ~ ~-:..-----...... - - unconformable depositional contact over ------...... the weathering crust of gabbro-diorites, diorites, -- ...... ' ------...... , quartz-diorites, granodiorites and plagiogranites ~ ...... ,, ------~ ...... , --~, (Strouma diorite formation). c.• of -·- · ~' '', The tectonic structure of the area is s\l~\0. ..--\;c.lin•· -.<...... ~~~··~' , ' ,, ·o.' ~ o" ~~~~~'-\:: ' ,, dominated by the rigid block (Lisiya basement .o1-'.....-"':.ti"0 ,7 ·~ ' ,, _, .,.. / , -- \ \ fragment) in the core of the Belirid anticline /\"t>• 1 / 1/ ,;' "', I \1 I I / ' I I (trending NNW-SSE), and the Skrino anticline ssw ~, I I I ' NNE l'!' 100 _,. 1 I I MutYOdol tuO/ that has been formed to the North of the former, I \ I I t ~0 0 along the initial course of the Poletintsi-Skrino zone, in the oblique WNW-ESE trend (Fig. 1, 400 7 2). The first movements are referred to the Late ~~~z~JI:-7::..:j,~s§§e~7 ~ 1 Triassic times, and formed the south-vergent " Vlashkidol anticlines complicated by south­ " vergent imbrications. In Jurassic times, this zone probably represented a barrier that divided the marine basin within the future Luzhnitsa-Trun Unit to the North from the uplifted Osogovo­ Vlahina Unit to the South. The formation of the Skrino anticline within the area of the Poletintsi­ Skrino zone occurred most probably in Mid­ Cretaceous times, during the folding of the whole Strouma Superunit, and was followed by the Fig. 5. Structural cross section and stereograms for the Northeast-vergent thrusting of the Morava over Murvodol anticlinaloid (after Zagorchev, 1981, Fig. 8). 1 - Paleogene; 2 - lskur Carbonate Group; 3 - Svidol the Strouma Superunit. Within the Poletintsi­ Formation; 4, 5-Murvodol Formation (Lower Triassic): Skrino fold-thrust zone, this movement was 4- Kalenitsa Member, 5- Boyna-chouka Member, 6- expressed in the northeast-vergent overturning Skrino Formation (Permian); 7 - Strouma diorites; 8 - of the whole Skrino anticline in such a manner thrust surface. 0 - bedding, 70 measurements, 1-3-5- 1 (Figs. 3-5) that the core of the anticline formed - 8%, fold hinges (triangles). 0 2 slaty cleavage, 53 measurements, 1-2-4-8-12%, X-axes of the total strain the Murvodol Synclinaloid (synformal anticline) (crosses). Upper hemisphere, equal-area net to the North of the Murvodol Anticlinaloid (antiformal syncline). The core of the anticlinaloid is exposed (Figs. 3, 4) South of the village of Murvodol opposite the old graveyard and the ruins of the mediaeval church. It is built up of the beds of the Mogila Formation in antiformal structure, covered in overturned position (upside down) by the beds of the Svidol Formation, and (towards South, along the country road), by the Kalenitsa and Boyna-chouka Member of the Murvodol Formation, and by the Vlashkidol and Vodenicharski Member of the Skrino Formation. The latter is covered tectonically by the Strouma diorites along the Skrino thrust (Fig. 5). The strain analysis (Zagorchev et al., 1976, 1979; Zagorchev, 1980, 1981) based on the study of different strain indicators (mostly, reduction spots) shows (Fig. 6) that: i) the total strain ellipsoids in the periformal part of the anticlinaloid are of a slightly prolate type, and the X -axes (maximum elongation and stretching) plunge WNW, parallel to the hinge of the Skrino anticline and to the Poletintsi-Skrino fold-thrust zone that is probably related to the exchange of the principal strain axes during the progressive deformation; ii) the total strain ellipsoids within Fig. 6. Strain partitioning (total strain) in the eastern part of the Poletintsi- Skrino fold-thrust zone (after Zagorchev, the southern, overturned limb of the 1981, Fig. 15). Ornaments for the geological part as on anticlinaloid (and northern limb of the Skrino Fig. 2 anticline) are characterized by the same trend 68 5 1 2

l95-1so 1 3

0 1 2 3km

Fig. 7. Sketch for the late Early Alpine deformations in the eastern part of the Poletintsi-Skrino fold-thrust zone. 1 - X-axes of late deformations after fibrous quartz crystals in Alpine veins; 2-striae on slickensides; 3- temperatures of formation of quartz Alpine veins (after measurements of Margarita Krusteva) of the X -axes but the ellipsoids are of normal mahala hamlet of the village ofPastouh is a SSSI (plane strain) to strongly oblate type (and very due to several unique features for Bulgaria and high strains), with a considerable flattening the Balkan Peninsula, and namely: i) unique within the cleavage planes, and considerable exposure of a whole antiformal syncline thickness reduction; iii) the deformation (anticlinaloid), with clearly defined core and conditions reached the boundary between very southern limb (G according to the GGWG low metamorphism (anchimetamorphism) and classification); ii) well defmed stratigraphic units, greenschist-facies metamorphism, and occurred most of them dated, and well dated upper age most probably in Aptian times as witnessed by limit of the deformations; iii) stratotypes of the the K -Ar studies (Lilov, Zagorchev, 1993); iv) Murvodol Formation and its two members the late deformations, including during the (Boyna-chouka and Kalenitsa Member) and of formation of fibrous calcite and quartz veins, the Vodenicharski and Vlashkidol Member of point at the same orientation of the principal the Skrino Formation (GGWG classification - strain axes (Figs. 6, 7). E); iv) abundance of strain indicators (mainly, The whole structure is covered with a reduction spots), and perfect possibilities for depositional unconformable (angular and demonstration of different structural features, structural unconformity) contact by Paleogene as, e.g., bedding/cleavage relationships in an (Upper Eocene - Lower Oligocene) sandstones overturned limb, total strain ellipsoids, etc. and claystones. The structure and the covering (GGWG Classification - G); v) good exposure Paleogene sediments are intersected and of an Alpine thrust (Skrino thrust) with a very displaced by normal faults and NE-vergent contrasting contact between allochthone reverse faults (Zagorchev et al., 1979, Fig. 14). (greenish diorites) and autochthone (red and purple Permian slates and siltstones) (GGWG Conservation issues. The section between the classification - G). These features are the basis village of Murvodol and the Vodenicharska- for the proposal of inclusion of the site in the 69 I : : : 11 ,...... : ·. :-:.j ··...... ····· ··2 fS'&$13 ~~~~ 'ca~ ~6

~7

' 0 I •t!. lo ., eO • 0 • j • • .;•o.ojP ~ / • •o• • I.o ·~·~ o I I-- f @/ • 8 0 9 ® 10 X 1'1 & 12 • 13

Fig. 8. Geological map of the area of the Gurbino thrust (after Zagorchev, 1984, Fig. 10). I - Iskur Carbonate Group (Middle- Upper Triassic); 2- red beds of the Petrohan Terrigenous Group (Lower Triassic); J- Strouma diorite formation and Frolosh Diabase-phyllitoid Formation; 4 - serpentinites; 5 - thrust with dip of thrust plane; 6 - cleavage and X-axis of total strain; 7- bedding; inset - structural stereogramme (upper hemisphere, equal-area net): 8 - bedding, 9- slaty cleavage, 10 - axial planes of minor folds, II - X-axis of total strain, I2- lineation and hinges of minor folds, JJ - thrust and fault surfaces

Bulg GHL and Balkan GHL. The manner of big quarry mined in the Middle Triassic conservation and exposure for educational and limestones and dolomites in the left bank of the scientific purpose should be discussed by the river Strouma, in the southern part of the Zemen professionals in the domain of geosite con­ Gorge of this river. servation. The normal section of the Triassic along the Zemen Gorge (from the top to the bottom) consists of the foJlowing formations (Budurov Gurbino thrust in the road cut towards et al., 1995): the quarry, village of Gurbino (GT) - Moesian Group, Komshtitsa Formation (more than 100m; Norian): red siltstones, shales The Gurbino thrust is situated in the base of the and polymictic sandstones, with interlayers of normal NNE limb of the Zemen monoclinorium oligomictic quartz sandstones, conglomerates North of the vilJage of Ruzhdavitsa (Figs. 1, 8). built up mostly of Triassic limestone pebbles, It is followed on a distance of about 2.5 km, and few limestone beds with Norian forami­ and is best exposed along the road towards the nifers; 70 - Iskur Carbonate Group: of at least 2.5 km (Figs. 8 - I 0). It belonged to Trun Formation (more than I 00 m; Carnian the basement of the Triassic section, and - Norian) - light-grey to whitish massive, represented a favourable medium (due to high aphanitic limestones with Algae; ductility and water saturation) for strain Radomir Formation (more than 200 m; Upper concentration and decollement (detachment) Anisian to lowermost Carnian) -dark-grey to during the Alpine deformations. The allo­ blackish nodular limestones with shaly interbeds, chthone is built up of the normal section of the shales and marls, with abundant macro- and north-eastern limb of the Skakavitsa anticline microfauna; as described here above cut at the level of the Bosnek Formation (varying between 200 and Svidol Formation (favourable rheological 700 m; Anisian) - light-grey to dark-grey features, namely-high ductility and rheological dolomites and dolomitic limestones; contrast between different rock varieties) and Mogila Formation (less than 5 m; lowermost the sandstone formation together with the Anisian)- dark-grey limestones; underlying ultramafics. The rocks of the pre­ Svidol Formation (5 - 15 m; Spathian) - Permian basement (Frolosh Formation, diorites) interbedding of yellowish marls, limestones, covered by the Lower Triassic sandstone light-red shales, some sandstones and dolomites; formation and Svidol Formation form the - Petrohan Terrigenous Group, sandstone autochthone. The rocks underwent a very low­ formation (15 - 30 m): whitish arkosic or grade (anchimetamorphism) to greenschist­ oligomictic quartz sandstones, red polymictic facies metamorphism during the thrusting. The sandstones and conglomerates, phyllitized red, age of deformation and metamorphism is not purple or whitish shales and siltstones; precisely determined. It is pre-Paleogene, and - base: metadiabases and actinolite and may be referred either to the Late Triassic ("Early chlorite-actinolite schists (Frolosh Formation) Cimmerian") movements coeval to the with bodies of ultramafics and gabbro, locally formation of the Vlashkidol anticlines and with diorites and granites. imbrications, or else to a Late Cretaceous south­ The Gurbino thrust (Zagorchev, 1984, 1985) vergent thrusting in "piggy-back" fashion, after is a southwest-verging structure in the northern the Mid-Cretaceous NE-vergent thrusting. normal limb of the Skakavitsa anticline. The uniqueness of the structure comes from the Conservation issues. The uniqueness of the presence of a 3 - 5 m thick plate-like lamella site as a SSSI comes from the almost perfect of serpentinized lherzolite that is exposed within exposure of a very rare or even unique structural the thrust plane, and is followed at a distance feature: the presence of a thin allochthonous

!100

250

0

0

Fig. 9. Cross sections through the northern limb of the Skakavitsa anticline and the Gurbino thrust; see points 1-4 on Fig. 8 (after Zagorchev, 1984, Fig. 11). I- Paleogene; 2- flysch (Kostel Formation, Tithonian- Berriasian); 3- red beds (Komshtitsa Formation, Norian); 4 - lskur Carbonate Group (Spathian - Norian); 5 - Petrohan Terrigenous Group (Lower Triassic); 6- Frolosh Formation, Strouma diorites (Paleozoic); 7- serpentinites; 8- slaty cleavage; 9 - thrusts and faults

71 approach has been gradually changed by Zagorchev, Sapund.zhiev (1982) and Dodekova et al. (1984), and resulted in the introduction of a Treklyano Group that represents a condensed section of almost the whole Jurassic formed within a special Treklyano sedimentation zone (Zagorchev, Tikhomirova, 1986; Zagorchev, 1986). The section crosses the eastern part of the Treklyano semi-klippe (Fig. 11, 12) of the Mid­ Cretaceous Penkyovtsi thrust sheet (Morava Superunit) and the underlying autochthone of the Luzhnitsa-Trun Unit of the Strouma Superunit. The Triassic and Jurassic section of the autochthone is intensely folded in isoclinal folds, and imbricated. The section is repeated several times with slight to substantial differences of the Jurassic part, and the transition from the argillite formation towards the normal Jurassic section of the Svetlya sedimentation zone is crossed by the borehole at Zemen (Zagorchev et al., 1990) and in the section Gorna Glogovitsa. The Strouma Superunit is built here by the Iskur Carbonate Group (Triassic), the following red beds of the Komshtitsa Formation (Norian), and the r r • 3 Treklyano Group and its lateral correlate - the r & 4 argillite formation. A brief description of the r r r e s Triassic part of the section along the Zemen Gorge ~------~--~~----~~ of the river Strouma is cited hereabove (Gurbino Fig. I 0. Field sketches and structural stereogramme (upper thrust). The Jurassic stratigraphy is described by hemisphere, equal-area net) for the outcrops of the Zagorchev, Tikhomirova (1986) and Zagorchev et Gurbino thrust (after Zagorcbev, 1984, Fig. 12). 1- lskur al. (1990). New data are obtained recently by Iliana Carbonate Group (Spathian - Norian); 2 - Petrohan Boncheva (radiolarians) and Kristalina Stoykova Terrigenous Group (Lower Triassic); 3 - serpentinites. On the stereogramme: 1 - bedding; 2 - slaty cleavage; 3 (calcareous nannoplankton). - thrust; 4 - lineation; 5 - 1t-axis The section Rayantsi is isoclinally folded, and consists (Figs. 11 - 13) of several sections of the Treklyano Group, some of them in normal; sheet of serpentinized ultramafics from the pre­ and others, in an overturned position. The type Permian basement inserted along the surface of section (stratotype designated Rayantsi-East) of an Alpine thrust. These features make the site a the Treklyano Group (Zagorchev, Tikhomirova, valuable candidate for inclusion in the Bulg Gill.. 1986) consists entirely of dark grey (with a and for the Balkan GHL. The manner of greenish shade) slates (argillites) and siltstones conservation and exhibition for educational and with thin (usually I - 15 em, only two of them, scientific purpose should be further discussed, correspondingly 1 and 1.1 m) interbeds of and practical steps undertaken by the National radiolarites built up exclusively of radiolarian Agency for Nature Protection. shells, and isolated thin (2- 5 em) sandstone interbeds. Only radiolarians have been found, Section Dobridolski-vodenitsi­ and in more than 30 samples studied (K. Rayantsi bridge (RA) Stoykova, oral communication, 1995) no calcareous nannoplankton has been observed. The section between the locality Dobridolski­ The total thickness of the Rayantsi Formation vodenitsi and the bridge at the former village of in the present highly deformed state (cleavage Rayantsi is the unique relict of a relatively deep practically parallel to bedding) is about 20 m, Jurassic marine environment preserved under and the basal conglomerates and sandstones of the thrust sheets of the Morava Superunit. These the underlying Dobridol Formation are about sediments have been described first by Nachev 3.5 m thick. The section is conventionally (1969) as formed in a local muddy environment subdivided (on the basis of radiolarian taxa of Middle Jurassic age within the shelf determined in thin sections) into the following calcareous sediments of the same age. The parts:

72 cover: Kostel Formation (Middle Tithonian -Middle Berriasian), flysch (not exposed in the stratotype but well exposed in other sections as Rayantsi-West, Oushtrintsi, etc.): fine- to me­ diuni-grained polymictic sandstones interbedded with greenish shales and siltstones, and near the base, with polymictic fine-pebble conglomerates with abundant limestone, sandstone, lydite etc. pebbles normal depositional contact (presumed parallel unconformity and short hiatus) Rayantsi Formation (upper parts of Lower Jurassic- Upper Jurassic): black and greenish slates interlayered with radiolarites and polymictic sandstones - beds IV (2 - 5 m) - Oxfordian - Kimmeridgian? age based on the radiolarian association (determined by L. Tikhomirova in thin sections) with Mirifusus guadalupensis Pessagno; -beds III (3.50 m) -Callovian - Oxfordian age based on a radiolarian association with -g Gongylothorax sakawaensis Matsuoka and "10 Guexella nudata (Kocher) determined by L. Tikhomirova in thin sections; -beds II (4.50 m) with Cyrtocapsa? kisoensis Yao, Dicolocapsa conoformis Matsuoka and Tricolocapsa plicarum Y ao (determinations of L. Tikhomirova in thin sections), referred to the Middle Jurassic (Aalenian -Lower Callovian?); - beds I (8.40 m) with a supposed Lower Jurassic age (determinations in thin sections by L. Tikhomirova of an assemblage with Bagotum modestum Pessagno & Whalen and Droltus hecatensis Pessagno & Whalen but with the presence of typical Middle Jurassic taxa of the Tricolocapsa plicarum Zone; in diluted samples, I. Boncheva confrrmed only the Middle Jurassic taxa. thus shifting the age interval to Aalenian - Bajocian (with possible presence of uppermost Lower Jurassic) Dobridol Formation (3.50 m; Lower? - Middle? Jurassic): conglomerates and sandstones with occasional slate interbeds base: Komshtitsa Formation (Norian): red or Fig. 11. Geological map of the area between the Rayantsi greenish slates and siltstones interlayered with bridge and the locality Dobridolski-vodenitsi (after quartz sandstones. Zagorchev, Tikhomirova, 1986, Fig. 2). 1 - Quaternary and Neogene; 2 - allochthonous Paleozoic (Treklyano In the section Rayantsi - West, mostly in semi-klippe of the Penkyovtsi thrust sheet, Morava overturned position (Zagorchev, 1984, Fig. 3), Superunit); 3 - flysch (Kostel Formation. Tithonian - the Dobridol Formation is thicker than in the Berriasian); 4-Treklyano Group (Jurassic); 5-red beds stratotype section at the village of Dobridol and (Komshtitsa Formation, Norian); 6 - Iskur Carbonate in the section Rayantsi - East, and exhibits a Group (Middle-Upper Triassic); 7-radiolarite samples; transition to an olistostrome character. The 8 - thrust; 9 - fault; 10 - bedding. The section Rayantsi relatively small (decimetric) fragments of limestones, shales and radiolarites contain Triassic microfossils (V. Ya. Vuks in Zagorchev, fragments). The Lower? (determinations of Tikhomirova, 1986), and their lithology and radiolarian assemblages in thin sections by L. microbiofacies is alien to all known Triassic Tikhomirova) Jurassic shales that form the exposures in that part of .the country (exotic matrix contain locally ichnofossils (Dodekova

10 73 sw , NE

Fig. 12. Generalized cross sections across the Treklyano semi-klippe. I - Paleogene, Neogene and Quaternary cover; 2- Paleozoic of the Treklyano semi-lclippe; 3-flysch Kostel Formation (Middle Tithonian -Middle Berriasian); 4- Treklyano Group (Jurassic); 5, 6 - Komshtitsa Formation, Norian: 5 -red beds, 6 - limestone interlayers with Norian foraminifers; 7 - Iskur Carbonate Group (Spathian - Norian); 8 - red beds of the Petrohan Terrigenous Group (Lower Triassic); 9 - thrust, fault; IO - slaty cleavage

~-~~1 2~J • R6 ~ _.;' s = 6

Fig. 13. Detailed section (stratotype of the Treklyano Group; drawn after series of field photographs) along the road between the Rayantsi bridge and the locality Dobridolski-vodenitsi (from Zagorchev, Tikhomirova, 1986, Fig. 4). I - slates and siltstones; 2 - radiolarites; 3-sandstones; 4- location and number of sample with radiolarians; 5-thrust; 6 - local scale (1 m)

74 Middle Alpine (Austrian) phases

Early Cretaceous (before Austrian phase)

Middle- Late Jurassic deep sea with clays and d i abase oc tlvi I y . . .. --­-"""' • • + • • • • • • + + + • • "' i• r"r•r•r• • trouma Superuni t + + •

VAROAR ZONE ~ li5:5:9 155!3 c:::::::::~ I:.... ,- ... ·-:J ~ ~ ,...... -, ~1 ~2 ~3 c=::::=J' liJJIJ 5 . · . ..· .. 6 ~7 ~8 L.!.__!l9

Fig. 14. Tentative reconstruction for the Vardar Zone, Morava and Strouma superunits, in Jurassic and Early Cretaceous times (after Zagorchev, 1986, Fig. 6). Inset: columnar sections for Treldyano (Tr), Svetlya (Sv) and Lyubasha (Ly) sedimentation zones: I, 2- Upper Jurassic- Lower Cretaceous: I- flysch (Kastel Formation), 2- Neshkovtsi Formation (Kimmeridgian), mainly marls; 3 - carbonate development, pelagic to littoral; 4- terrigenous Lower - Middle Jurassic (Gradets Formation); 5-deep-sea slates with radiolarites; 6- continental Lower Jurassic (Zhablyano Formation); 7 -basic volcanics of Vardar Zone; 8- ophiolitic basement of Vardar Zone; (T) -Triassic formations as pre-Jurassic basement. Cartoon sections: I , 2 - Tithonian - Berriasian: I - flysch, 2- carbonate formations; 3 , 4 - Middle - Late Jurassic: 3 - terrigenous and carbonate, 4 -deep-sea clays with radiolarites; terrigenous, marine (Early- Middle Jurassic); 5- Triassic carbonate and terrigenous formations; 6 -Permian formations; 7- oceanic basement of Vardar Zone (ophiolites); 8- continental basement of Kouchay type (Precambrian and Paleozoic); 9 - continental basement of Vlahina type (Precambrian and Vendian-Cambrian) et al., 1984) of the genus Chondrites Sternberg - alternation of shales and siltstones with (known also from the section Oushtrintsi where sandstones, and rarely, oolithic and biodetritic isolated and very deformed belemnites and a limestones (14m) with the foraminifers Bolivina single Punctaptychus sp. have been found). liassica (Terquem), Protopeneroplis cf. striata The overturned section East of the section Weinschenk, Discorbis scutiliformis (E. & I. designated as Rayantsi-East, in close proximity Seibold), Lenticulina cf. quenstedti (Guembel); to the Rayantsi Bridge, exhibits an argillite­ possible age - Pliensbachian - Bathonian . .K. siltstone formation ·with sandstone and (rarely) Stoykova (oral communication, 1995) found in limestone interbeds. The section is as follows three of the samples calcareous nannoplankton (Zagorchev et al., 1990): fossils ranging from the Toarcian to the Kostel Formation (Middle Tithonian - Valanginian, and known as the taxa most Middle Berriasian): polymictic conglomerates resistant to dilution at deeper sea levels; (exposed next to the bridge) built up of pebbles base: Komshtitsa Formation (Norian): red of quartz, Triassic and Jurassic limestones, and greenish slates and siltstones interbedded sandstones, etc., interbedded with polymictic with red sandstones. sandstones, and in the lower part, with siltstones The total length of the section is about 600 argillite-siltstone formation (uppermost m, and in the westernmost parts it is overthrusted Lower? Jurassic or Middle Jurassic -Upper by the Paleozoic of the Penkyovtsi thrust sheet Jurassic): that belongs to the Morava Superunit. Numerous - alternation of polymictic sandstones, imbrications are exposed by the section. siltstones and shales (30 m); single finding of The palaeogeodynamic importance of the Watznaueria barnesae (study by K.. Stoykova, section between the Rayantsi bridge and the lo­ 1995, oral communication) cality Dobridolski-vodenitsi comes from its

75 uniqueness within the southern margin of the identical to the Strouma diorite formation but Triassic Moesian "platform". It can be inteipre­ subject of strong superimposed deformations. ted (Zagorchev, 1986) either as a fossilized tran­ The lowest Dragovishtitsa thrust sheet is built sition from the shallow sea of this margin towards up of Middle to Upper Triassic dolomites and the continental slope to the Jurassic Vardar Ocean limestones, the Norian red beds of the (Fig. 14) or as a fossilized deep Jurassic gulf Komshtitsa Formation, and the blackish shales similar to the present-day Gulf of California. (with siliceous and phosphatic concretions) and radiolarites of the Treklyano Group. Very high Conservation issues. The value of the sections strains as well as several phases of deformation studied as a SSSI is based upon: i) it is the are recorded (Zagorchev, Sapundzhiev, 1982). stratotype of the Treklyano Group and its Folds at the base of the Dragovishtitsa thrust Rayantsi Formation, and contains abundant (beneath the clear-cut slickenside) point at a radiolarian and rare calcareous nannoplankton southern vergence. The next thrust sheet and foraminifers (E, A); ii) presence of (Poletintsi thrust) is an element of the Mid­ condensed deep marine facies of the Jurassic Cretaceous northeast-vergent Penkyovtsi Unit unknown in other places in Bulgaria as well as of the Morava Superunit. It is built up of of transition facies (C); iii) tectonic Ordovician? phyllites and metadiabases, rapprochement by folding, imbrication and Silurian? and Devonian slates, and Devonian thrusting of different facies of Jurassic rocks, limestones and polymictic metaconglomerates with considerable palaeogeodynamic impor­ and metasandstones all intruded by Hercynian tance (G, J); iv) exposure of important thrusts diorites to plagiogranites. Intense deformations and imbrications {G). The uniqueness of the site and very high strains are related partially to the for Bulgaria, and in some aspects, for the Balkan Late Hercynian deformations, and partially, to Peninsula, is the reason to be proposed for the the Mid-Cretaceous thrusting. At its northern Bulgarian and the Balkan GHL. The border, the Poletintsi thrust sheet (in fact, a semi­ conservation should take into account the klippen) is thrusted over the Triassic section of ongoing works for the dam and artificial lake the Zemen monoclinorium. A third thrust sheet Kalotintsi, and the fact that the presently existing (Manchov thrust) covers with a clear-cut asphalted road will be cut and closed exactly in slickenside the Paleozoic rocks of the Poletintsi its most interesting sector: this part should be sheet. It is built up mostly of the Carnian - conserved as an open-air museum. Norian limestones of the Trun Formation, and according to the scarce data, is of an eastern vergence. The whole pile of thrust sheets (Ouyno Section along the river Poletinski-dol allochthone) is sealed by Paleogene (Upper (P1) Eocene- Oligocene) conglomerates, sandstones and shales, locally with huge olistostromes built The section has been discussed by Zagorchev up of Triassic (Trun Formation) limestones. (1968) on the basis of former mapping by Another opinion (Bakalov et al., 1983) considers Sapundzhiev et al. {1964, unpublished map and the Manchov thrust sheet as huge olistoliths report). Moskovski (1972) made a good within the sealing Paleogene olistostrome. Other description of the Dragovishtitsa thrust. L. B. pending problems concern the sequence of the Tikhomirova {1981; conclusions of microscopic deformation events, and namely, of the thrusting. studies on specimens of Zagorchev) determined The south-vergent thrusting (Dragovishtitsa for the first time a Jurassic age for shales thrust) is regarded as the first thrusting event previously referred to the Paleozoic of the followed by the northeast-vergent thrusting Poletintsi thrust. These new facts became, (Poletintsi thrust) of the Penkyovtsi Unit, and together with a detailed structural mapping, the the last thrusting {Manchov thrust) may be even crucial evidence for a totally new understanding a Paleogene gravity event coeval with the of the section {Zagorchev, Sapundzhiev, 1982). olistostrome formation. On the other hand, the The structure of the area {Figs. 1, 15, 16) south-vergent thrusting of the Dragovishtitsa consists of a relative autochthone and a pile of thrust might be (entirely of partially) younger thrust sheets formed as a result of Mid-Creta­ (Late Cretaceous) than the Poletintsi thrust, and ceous and Late Cretaceous thrusting events; the the Poletintsi thrust sheet might be in such a whole structure is sealed by Paleogene (Upper case transported southwards in a piggy-back Eocene - Oligocene) sedimentary formations. fashion. The relative autochthone is built up of the Lisets diorites, - an igneous formation consisting of gabbros, gabbrodiorites, diorites, quartz-diorites, Conservation issues. The importance of the granodiorites and plagiogranites, similar or even site as a SSSI is mainly related to the structural

76 I ·-1, C] c=J1 ~3 ~' 5 ~6 ~ 7 1-...+1, illill g ~10 ~, 13 ---- 12 ~ _,.,. " 0 100 200 300 400 500m ------

SECTION 1-2 SECTION 3-4 aoo SW NE

Fig. 15. Geological map and cross sections of the area of the Poletintsi and Dragovishtitsa thrusts near the village Poletintsi (after Zagorcbev, Sapoundzhiev, 1982, Fig. 5). 1 - Quaternary; 2 - Paleogene; 3 - Treklyano Group (Jurassic); 4. 5- Komshtitsa Formation (Upper Triassic): 4- oligomictic sandstones, 5- red siltstones; 6 - Islrur Carbonate Group (Middle - Upper Triassic); 7 - Lower Triassic; 8 - schistose Hercynian granites; 9 - Paleozoic epimetamorphic rocks; 10 - dioritic blastomylonites; 11 - thrust, 12- fault; 13 - schistosity and lineation; 14- schistosity in red beds with X-axis of the total strain features (G according to the GGWG classi­ with the beautiful and contrasting exposure of fication), and several sectors can be chosen for the Dragovishtitsa thrust sheet, the foot particular conservation as, e.g., the side ravine slickenside of the Dragovishtitsa thrust with the 77 schistified diorites practically transformed into green schists (phyllonites), that contain several small lenses (1 - 5 m thick) built up of strongly brecciated brownish marmorized limestones. The degree of deformation is the strongest at the boundaries of these lenticular bodies, and they are interpreted as sitliated within the surface of a south-vergent thrust (Tsurvishte thrust) that occurred in greenschist-facies conditions. Although samples from the limestones have been studied in thin sections and processed for conodont and foraminifer studies, no micro­ fossils or their debris have been found. However, on the prolongation of the thrust surface along the Tsurvishka river above the road, two thin (0.5 m) lenses of highly deformed and metamorphosed (very low grade to greenschist facies) red sandstones have been found that could belong either to the Skrino Formation (Permian) or to the Murvodol Formation (Lower Triassic). This finding points at a most probable Triassic age for the limestone lenses. Thus, the outcrop of the Tsurvishte thrust represents a SSSI similar to that of the Gurbino thrust but of a slightly different nature: insertion of lenses of Fig. 16. Field sketches for the Dragovishtitsa thrust (after younger rocks within a thrust surface affecting Zagorchev, Sapoundzhiev, Fig. 13). 1 - thrusting of mainly rocks of their basement. A similar case Triassic carbonate rocks of the Dragovishtitsa thrust sheet (I) over folded dioritic blastomylonites (2) in the river has been described in the Osogovo Mountains Poletinski-dol north of the bridge; 2 - left ravine - (Zagorchev, Ruseva, 1982) where dolomites with confluent of the river Poletinsld-dol: Paleozoic schists and relics of Anisian foraminifers are preserved as granites of the Poletintsi thrust sheet (1); Dragovishtitsa thin lenses within the surface of the Eleshnitsa thrust sheet: whitish oligomictic sandstones (2) and red thrust. polymictic sandstones and slates (.() of the Komshtitsa Formation (Norian), Jurassic Treklyano Group (3), Triassic lskur Carbonate Group (5); relative autochthone Conservation issues. The interest towards the - schistous folded dioritic blastomylonites (6) Tsurvishte thrust comes from the excellent exposure of a thrust formed at moderate depth and marked by lenses of the cover formations thrust-bound south-vergent folds in the Lisets inserted within the thrust surface . This is not a diorites, etc. The site is nominated for the unique or very rare structural feature but the Bulgarian GHL. good exposure makes this road cut a good candidate for the Bulg GHL, as well as a possible Tsurvishte thrust in the road cut near candidate for the Balkan GHL. the village of Tsurvishte (TS) Conclusions The road cut from the village of Dragodan towards the village of Tsurvishte (Figs. 1, 2, 7) Five geotopes are proposed for inclusion in the exhibits a unique structural feature, and namely, Bulgarian Geological Heritage List, and three the Tsurvishte thrust (Zagorchev, 1981 ). The of them (Murvodol Anticlinaloid, Gurbino road is traced across the rocks of the Strouma Thrust, Rayantsi Section), the Balkan GHL, and diorite formation: gabbrodiorites, diorites and to be conserved by the National Agency for quartz-diorites, granodiorites and plagiogranites, Nature Protection in a manner that would permit the latter being metasomatically transformed (K their preservation and exhibition for educational and Si metasomatosis) into normal granites, and and scientific purposes. The geotopes have a intersected by pegmatite veins. They are cross­ complex character, the main features charac­ cut by numerous dykes built up of dolerites, terizing them as SSSI (in brackets - according microdiorites and lamprophyres. to the GGWG classification) being: The road cut at the sharp curve opposite the - stratotypes of formal lithostratigraphic village of Tsurvishte exposes highly strained units (E): parts of Skrino Formation and Mur-

78 vodol Formation (Murvodol Anticlinaloid), Dodekova, L., Sapunov, 1., Tchoumatchenco, P. 1984. Rayantsi Formation (Rayantsi Section); (.l{o,AeiOBa, Jl., CaJJYBOB, H., q)'Ma'leHI:O, n. 1984. CTJ)aTHrpa$HJI aaneacux, 6aloccna a 6aTcna OT­ - palaeobiological features, palaeoenviron­ no:aead s '18CTH 10ro-3ana.ABOA lionrapRB). - ment (A, C): Rayantsi Formation (Rayantsi Geologica Balcanica, 14, 2; 3-55. section); Lilov, P., Zagorcev, I. 1993. K-Ar data for the deformations - excellent exposure of important structural and low-grade metamorphism in Permian and Triassic features (G), as relations between cleavage and red beds in SW Bulgaria. - Geologica Balcanica, 23, S; 46. bedding, folds, thrusts and imbrications, strain Moskovsld, S. 1972. (MOCI:OBCDI, C. 1972. 0CTaUR OT indicators, etc. (all five sites); H8Bn81: B DO,An0:ai:8T8 Ra llonCTHHCUJI poB).- FoO. - excellent exposure of unique structural and COI/J. y-mem. re011. -zeozp. tjjaK., lal. 1 - ze011. (Ann. complex geological features (G): Murvodol Univers. Sofia, Faculty of Geol. & Geogr., No 1 - Anticlinaloid, Gurbino Thrust, Treklyano Semi­ Geology), 64; 97-105. Klippe and underlying intensely folded and Nachev, I. 1969. (Ha'leB, H. 1969. Jhnononu aa xeT8Jfl(­ I:HMepa,A:acoTe ceAHMeHTH B Kpaim.eTo). - H36. imbricated section; reoJJ. UHCm., cep. Cmpamuzp. u .llUmOJJ. (Bull. Geol. - preservation of a unique geodynamic Inst. Sofia, ser. Stratigr. & Lithol.), 18; 127-154. feature (J, L): the condensed deep-sea Jurassic Sapunov, 1., Chemyavska, S., Tchoumatchenco, P., section of the Treklyano Group, and its Shopov, V. 1983. (Canyaos, H., t{epHOcJ:a, C., q)'Ma­ 'lea.:o, n .. monos, B. 1983. CTJ)8THrp8~HJI HB:aHeJOp­ transitions through the argillite formation to the CDIX OTno:aeaaA s o6naCTa KpaHIDTe (10ro-3ana.n­ '"normal" Jurassic section of the Svetlya aulionrapD). - Geologica Balcanica, 13, 4; 3-29. sedimentation zone of the shelf sea. Sapunov,I., Tchoumatcbenco, P., Dodekova, L., Bakalova, Acknowledgements. The preparation of the D. 1985. (Canyuos, H., li)'M8'1eB.J:o, n .. ,l{o,AeJ:OB8, Jl., present paper has been partially helped liuanosa, .l{. 1985. CTJ)aTarpa$HJI xennoseAcmx a BepXHeJOpCJ:BX OTnO:a:eaBA J0ro-3ana,AHOI lionra­ (additional field work and sampling) by the pHR).- Geologica Balcanica, 15, 2; 3-61. ational Fund "Scientific Research" under the Tronkov, D. 1983. (Tpoa.:oB, .l{. 1983. CTJ)aTBrpa$B'Iec­ contract 204/92 on the project "Geologic evo­ ne npo6neMhl Hcx~:~~pc~:oA np6oaaTaoA rpynn~:~~ lution and palaeogeodynamics of Bulgaria in the (Tpaac), 10ro-3ana.AHU lionrapHJI). - Geologica Mesozoic and Tertiary". The help under the Balcanica, 13, 5; 91 -100. Zagorchev, I. 1968. (3arop'leB, HB. 1968. 0 AOnaneore­ same project made possible the study of radi­ HOBOM p83BBTBH floneTBBCIOA p83nOMROi 30Bhl). - olarians (Iliana Boncheva, paper in preparation) C.-R . .Acad. bulg. Sci. • 21, 10; 1089-1091. and calcareous nannofossils (Kristalina Stoyk­ Zagorchev, I. 1980. (3arop'leB, Hs. 1980. PaaaeanLnHilc­ ova, paper in preparation). I. Boncheva and ue .Ae$opM&URH B xpaCHOQBeTHhiX OTnOlll:eBHJIX flo­ K. Stoykova are thanked for the kind permis­ neTBHCI:O-CxpRHCJ:OA p83JJOMHOA 30Bhl. 1. J1HTOCT­ paTB-rpa$11'1eCDle OC06eHHOCTH BCBeTe CTpyrt)'J)HhiX sion to cite partially their unpublished results. sccne,Aosaad). - Geologica Balcanica, 10, 2; 37-60. This paper is a contribution to the newly-ap­ Zagorchev, I. 1981. (3arop'leB, HB. 1981. PauaeanLnRAc­ proved project 601/96 "The Geological Heritage ue .Ae$opM8UHH B xpaCHOUBeTHhiX OTnOlll:eBRJIX llo­ of Bulgaria: National Strategy and Sites of Spe­ neTHHCJ:o-CxpHHCIOil p83noMRoi 30ilbl. 2. CTJ)oeaae cial Scientific Importance" of the National Fund H Ae$opM8IUIR cesepaoA '18CTH BnaxRBcioro 6non). -Geologica Balcanica, 11, 1; 101-126. "Scientific Research". Zagorchev, I. 1984. (3arop'leB, H. 1984. Ponb H&.ABRTOB B am.naAc.:oM CTpoeBBH KpaHIDTH.A). - Geologica Balcanica, 14, 4; 37-64. References Zagorchev,l. 1985. (3arop'leB,If. 1985. P8HHOaJJDHiCJ:H Ae$OpM8UHR B 06XB8T8 Ha lloneTHHCJ:O-CxpHHCJC8T8 Anon. (lUGS Global Geosite Working Group). 1995./UGS p83nOMHa 30Ha. 4. Wano'laacn aHTHinHBana). - GEOSITES. Database on Geological Sites. Database CnucaHue Ha b'&JJzapcKomo zeOJJozu&recKo dpyxec­ form. mso (Review Bulg. geol. soc.), 46, 3; 287-298. Bakalov, P., Zhelev, V., Tronkov, D. 1983. (liuanos, ll., Zagorchev, I. 1986. Jurassic paleogeography of a part of }I(CJJeB, B., TpoHIOB, .l{. 1983. GrpaTHrpa$cu noJH­ South-West Bulgaria in the light of new stratigraphic JUIJI H p83npoCTpaHeHHe Ha TJ)HaCXJITC D'bCTJ)OUBeT­ data. - Geologica Balcanica, 16, 5; 3-20. HH 38JlpyrH s KoHocxaTa a 3eMeacxan ruJaHHHa). - Zagorchev,l. 1990. (3arop'leB, H. 1990. KoppCJIJIUHJI Melll:­ I1aJJeoHmoJJOZUJI, cmpamuzpatjjUJI u JJumoJJozUJI -AY TeUOHR'ICCJ:RMH e,AHHBQ8MR B 3088MB B norpa­ (Palaeont., Stratigr. & Lithology, Sofia), 18; 83-88. HH'IHhiX paAoaax 10ro-3ana.AHoA lionrapBH H lOroc­ Boyanov, 1., Dabovski, C., Gocev, P., Harkovska, A., nuRR). - C.-R . .Acad. bulg. Sci., 43, 7; 55-58. Kostadinov, V., Tzankov, Tz., Zagorcev, I. 1989. A Zagorchev, 1., Sapundzhiev, K.. 1982. (3arop'leB, HB., K. new view of the Alpine tectonic evolution of Bulgaria. CanyR.A::a:Hes. 1982. Paaaoanndcu Ae$opMaURH s -Geologica Rhodopica, 1; 107-121. 06XB8T8 HB lloneTBHCJ:O-CxpHHCJ:8T8 p83nOMR8 3088. Budurov, K.., Zagorcev, 1., Trifonova, E. 1993. The Triassic 3. Ybeacu anoxToB).- FeomeKm., meKmoHOI/Ju3. in Southwest Bulgaria. Upper Triassic red beds u zeoiJUHaM. (Geotect., Tectonophys. & Geodynamics, (Moesian Group) in the Golo-bardo Unit.-Geologica Sofia), 14; 3-29. Balcanica. 23, 5; 35-45. Zagorchev, I., Tikhomirova, L. 1986. (3arop'leB, H., Ta­ Budurov, K.., Trifonova, E., Zagorcev, I. 1995. The Triassic XOMHposa, Jl. 1986. CTpaTarpa~HJI JOpct:oATpein.IIH­ in Southwest Bulgaria. Correlation of key sections. - ct:oA rpynllhl (10ro-38D&.llBUlionrapHJ1)- Geologica Geologica Balcanica, 25, I; 27-60. Balcanica, 16, 3; 23-44.

79 Zagorcbev, 1., Tzankov, Tz. 1996. Geological sites of aea.m.mdcne Jlcc)opM&D;IDI B 3&JI&,IUIOI 'I&CTB Cq)BH­ special scientific importance (SSSI): an approach to aOIIUITIWIBBIUIII). -reomeKmOHUICil, meKmOHQ¢u- Bulgarian and Balkan geotopes. ·-Geologica Balcanica, 3UICil u zeoouHaMuJCa (Geotect., Tectonopbys. & 26, 1 (in press). Geodynamics, Sofia), 10; 31-61. Zagorchev,l., Tzankov, Tz., Sapundzbiev, K. 1976. Strain Zagorcbev, I., Trifonova, E., Toabev, A 1990. (3arop'leB, variation in a part of the Skrino anticline, District of H., E. Tpa4M>aoaa, A. Tomea. 1990. CoB.llam.T npa Kyustendil, determined from deformed reduction spots. leMea,IO~aa li'L1II'8pu- reono.KDI pelyJITil­ - C.-R. .Acad. bulg. Sci., 29, 9; 1333-1336. TB B TCri'OBCDI B3BOJlB). - FeomeJCmOHUICil, meJCmO­ Zagorchev, I., Tzankov, Tz., Sapundzbiev, K.. 1979. (3a­ Ho-t}U3UICil u zeOOUHaMUICil (Geotect., Tectonopbys. rop'leB, HB., Uauoa, ~.• CallyaAa:Bea, K. 1979. Pu- & Geodynamics, Sofia), 21; 43-70.

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