GEOLOGICA BALCANICA, 22.3, Sofia, Jun. 1992, 3-31,
Lithostra tigraphic features and structure of the Precam brian of the Rhodopian Supergroup in the lvaylovgrad and Krumovgraj area s, East Rhodope Mountains
Dimitar K ozhoukharov
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia
(Rec<: iued 22. 04. 1991 ; accepted 15. 11 . 1991) fl.. Ko:HCyxapoa - Jlumocmpamuzpai/Ju'ieCKUe oco6etmocmu u cmpoenue PoaonCKOU cynepzpynnbl ao Ke.M6pUJl a Jfaau/IOazpaacKo.M u Kpy,«oazpaactwAt pauonax, Bocmo'inble Poaonbl . Po~oncKaH cynep rpynna 11 V1saiL1os rpa~CKOM 11 KpyMosrpa~cKOM paiioHax npeJJ.crasJieHa nopoJJ.aMH Pyn'IOCCKOH rpynnbl, KOTOpb!e o6oco6.:rellbi B rpex cnwrax: 4eneJia pcrwif necrpoH crmre, 5oryrescrwlr nJiamorHelicosoJ:i cnw re 11 Bur'laHcKo!'i necrpoif cswre. 3TII TPH CBHTbi pa 3rpaHH•reH bi nnepnbre ]!.Jill 3TOH 1.1acrw Bocro'!ublx Poaon . fio.1ee oco6oe pa3BHTHe 3JJ.eCb HMeer 4eneJiapcKaH cswra, B Koropoii c 3ana~a Ha socroK, MC>KJJ.Y ceJiaMu Ila~a,1o 11 K aM II •lC KH-)loJI, s mnoJIOfH'IecKOM OTHOlliCHHH nocreneHHo o Abstract. The Rhodopian Supergrt?_up is represented in the l vaylovgrad and Krumovgrad areas by the rocks of the Rupcos Group: the Cepelare Varied Formation, Bogutevo Plagiogneiss formation, and Vaca Varied Formation. The three formations are distinguished for the first time in this part of the East Rhodope Mountains. The Cepelare Formation occurs here in a more specific manner. Three members are gradually outlined from the west to the east between the villages Padalo and Kamilski Dol. They have also a varied composition, but each of them is dominated by a particular rock variety: Yailadzik Member (mainly gneissose), Tumbata Mcmber(schists to gneiss-schists) and Kamilskido l Member (predominantly am phi bolitic). The members are introduced here for the first time. The rocks of the three members in- 3 tcdinger to the west and southwest of the village Popsko with the undivisiblc Cepelare Formation from the Avreil s yncline. The Bogutevo a nd Vii ca Formations (in incomplete sections) haye a compo sition and characteristi c fea tures similar to that in the type area, ar. d differ from the typical develop ment by the increased amount and dimensions of the ultrabasic bodies. The rocks of the Rhodopian Supergroup are pol ymetamorphi c prod uc!s which in their present shape are a result of multi phase s uperposition of metamor phic alterations (different in type and inten sity) during the Preca mbrian and the Phanerozoic stages of their deYelopment. With the exception of the low-temperature h yd rothermal meta morphi sm (serpentinization) ilnd the early hi gh-baric meta morphism proven for the meta ultrabcsics and eclogites , the metamorphic processes in all other rock varieties had the following sequence: Precambrian regional a mphibolite fa cies metamorphism; Pre cambrian (Riphean) regional migma tization; regional greenschi st facies diaphthoresis (at the Precam brian - Phanerozoic boundary); Early Alpine meta morphism (pregraniti c, pre-Upper Cretaceous); contact metamorphism rel ated to the Upper Cretaceous? graniti c intrusions; Late Alpine (Paleocene - Qua ternary) dynamomctamorphism. Introduction The Precambrian metamorphic rocks in the Ivaylovgrad and Krumovgrad areas of the East Rhodope Mts are di stinguished from the Paleozoic and Mesozoic low-grade to anchimetamorphic rocks by almost all geologists working in that part of the Rho dope Massif (5I p a 11 o B, 1960; YI BaH o B, 1961; Eo 51 HoB 11 .n.p., 1963,1969; Eo51HOB, JlHnMaH, 1973; Ko)Kyxapos, Ko)Kyxapoaa, 1984; Eo- 51 H o B, P y c e a a, 1984). The present paper deals with the metamorphic rocks of the Rhodopian Supergroup which are widespread within the scope of Kami !sk i do l syncline and along the northern periphery of the Bjala reka structure. The rocks of the Rhodopian Supergroup have been distinguished and mapped as a constituent of the so-called Proterozoic structural stage during the geological map ping on the scale 1:25 000 (Eo 5I HoB et al., 1963) in 1958 and 1960 without sub eli vision into smaller units. On the basis of the same mapping results, Yl B a 11 o B (1961) included these rocks into a formation designated as "upper varied formation M']" and showed its distribution on a geological map in 1:200 000. The boundaries of Rhoclopian Supergroup have been later corrected and defined more accurately during the compilation of a geological map of the East Rhodope Mts on the scale 1:50 000 (I. Boyanov, D. Kozhoukharov, A. Gora~ov, Z. Mazni kov, G . V a I eva, M. S pi r i dono v a, M. R use v a, Z . .S i 1 j a f o v a, unpub lished map, 1980). The present paper is based on a project (D. K o z h o u k h a r o v, E. K o z h o u k h a r ova, I. Boyan o v, I. Zag or c e v, unpublished re port, 1985) on the composition, structure and metamorphism of the Precambrian complexes of the East Rhodope block. The detailed subdivision of the Rupcos Group in the area studied was carried out by the present author within the scope of this project. Lithostratigraphic features of the Rupcos Group The Rhodopian Supergroup is represented in the East Rhodope Mts only by the rocks of the Rupcos Group (K o )K y x a p o B, 1986). Formerly, the same rocks have been referred to the so-called "lower metamorphic series - upper varied formation Mj" (Yl B a H o E, 196 1) , "Proterozoic structural stage" (Eo 51 H o B et a!., 1963), "Rho dope crystalline-schist series - upper varied stage R 4" (I van o v, 1965), "Protero zoic complex - lower varied formation Pt" (K o )K y x a p o a, 1968), "Upper Rhoda pian complex- varied suite Pt1" (K o z h o u k h a r o v et al., 1974), etc. Almost all researchers mentioned refer the metamorphic rocks from the Kami ! ski dol syncline to a single formation stating that the varied rock compos ition makes impossible a more detailed subdivision. This concept has not been changed also during later studi es when these rocks have been shown in the same sense and volume on the unpublished geological map of the East Rhodope Mts by I. Boyan o vet al. (1980). 4 A new geological map of the area on the scale 1:25 000 was made by the author in the period 1981-1988; the Precambrian metamorphic sequence was subdivided into forma tions, members and packets. These I ithostratigraphic units are the subject of the pre sent paper. The Rhodopian Supergroup and the Rupcos Group have been introduced by K o - )I{ y x a p o B (1984) with type region in the Central Rhodope Mts. The Rupcos Group consists in the type region of the C:epelare Varied Formation, Bogutevo Plagiogneiss Formation and Vaca Varied Formation; their presence in the Avren syncline (East Rhodope Mts) has been found later (K o )I{ y x a p o B, 1987). The investigated part of the Kamilski dol syncline and the northern periphery of the Bjala reka structure is a prolongation of the rocks of the Avren syncline towards east-northeast. All three forma tions have been distinguished for the first time also in that area between the villages Padalo and Huhta . Cepelare Varied Formation The C:epelare Formation is named by YI BaH o Bet a!. (1980) and defined with a more complete section by K o )I{ y x a p o B (1984). Both in the type region and in the other outcrops of the formation in the Rhodope Massif (K o z h o u k h a r o v, 1988), as well as in the Avren syncline (K o )I{ y x a p o B, 1987) the C:epelare Formation re- 0 , CJ2 ~3 § t. §s J0S 6~7 -8 ~· -·:jg E:SJ ,o Fig. I . Geological orientation map with ihe position of the section described 1 - Quaternary, and water-covered .areas; 2 - Pliocene sediments and Paleogene sedimentary and volcanic formations; 3 -- Upper Cretaceous(?) granitoids; 4-8 - Rhodopian Supergroup, Rupcos Group: 4 -- Vii ca \':1ried Fortn:~lion, 5 - Bogutevo Plagiogneiss Formation, 6-8 - Cepelare Formati on (6 - 1\amilskidol Mem ber, 7 - Tumbata .Member, 8 - Yailadzik Member); 9 - Pra rhodopian Supergroup; 10 - Pelevun thrust sheet; 11 - faults; 12 - section lines 5 presents an alternation of various gneisses, gneiss-schists and schists, marbles, amphi bolites, calcareous schists, aplitoid leptynites (quartzo-feldspathic gneisses), iron bearing quartzites, etc. In some regions, the gneisses predominate in the lower parts of the formation, gneiss-schists and schists occur in the middle parts, and the thicker amphibolite packets are concentrated in the upper parts. In the East Rhodope Mts east of the Avren syncline, three member:_s can be distin guished at the background of the generally varied composition of the Cepelare Forma tion, from the west to the east between the villages Padalo, Popsko and Kamilski dol. Although all three members have a varied composition each of them is dominated by a different rock. From the base towards the top these units are: Ya iladzi k ..Member (most! y gneissous), Tumbata Member (mostly built up of gneiss-schists and schists) and Kamil skidol Member (predominantly amphibolitic). These members are easily discernible in the field and are traced also laterally as continuous rock bodies. All three members are stabilized with type sections (fig. 1) and are introduced in the stratigraphic nomencla ture formally with the present paper. The holotypes of the members are parts of the com posite stratotype of the Cepelare Formation in this part of the Rhodope Massif. The pa ckets in the common sections of the formation and in the complementary sections bear (figs 2 and 3) the same numbering. Y a i 1 a d z i k M em b e r (5h1Jia)J.}KHWKH 4JieH) (new member) It is introduced here for the first time. Named after the peak Yailadzik, Ivaylovgrad region, where the holotype section and the most representative sections have been stu died. Historical notes. During all previous investigations, the rocks of the Yailadzik Member have not been distinguished as a separate lithostratigraphic unit being refer red to the varied formations (stages, suites) mentioned above. Composition. The Yailadzik Member is built up of a predominantly gneissous back ground of fine- to medium-grained two-mica gneisses locally passing into muscovite gneisses. A transition towards gneiss-schists in some thin layers is marked by the in crease of the mica content and decrease of plagioclase. Other rock varieties (two-mica and muscovite schists with or without garnet; biotite and two-mica garnet-bearing gneis ses; aplitoid muscovite leptynites; fine- and medium-grained massive and layered am phibolites in some layers with garnet and epidote) are present as separate layers with different thickness (from 0.2 to 8-10 m) or in a frequent alternation. Such a petrogra phic composition characterizes the member in its holotype section (fig. 2A) and south west of it towards the villages Baharsko and Konnici. More to the west, towards the villages Popsko and Belopolci, the relative quantity of amphibolites and gneiss-schists gradually increases. More to the south-southwest, in the direction of the Avren syn cline (K om y x a p o B, 1987) this tendency is even more pronounced, and the Yai ladzik Member is hardly discernible within the common alternation of the rock varJe ties in the Avren syncline. This gradual interfingering with rocks of the undivided Ce pelare Formation from the Avren syncline required a series of complementary sections to be studied (figs I, 3). Holostratotype (fig. 1, 1-I, and fig. 2A). It embraces the packets from 1 to 6 from the common section of theCepelare Formation which begins 500 m east of the peak Yailad zik and continues southeast of the peak along the road near the peaks Kyucukkale and Srebarnica, finishing 250 m southeast of the sheep-folds of the village Kamilski dol. Cover. The Yailadzik Member is covered by the first packet (packet 7 from the common section of the Cepelare Formation) of the Tumbata Member (medium- to fine-grained layered of massive amphi bolites with small boudin-like bodies of eclogites and metaserpentinites) with a sharp change of the lithology. Description of the section: Thickness, m 6. Biotite to two-mica gneisses, fine-grained, in some layers with garnet, and fine Augen structure...... 64.0 6 --~ Fig. 2. Complementary sections of the Ce pelare Formation (I-I ' II -I I and Ill-Ill from fi~. l) 5. Alternation of two-mica gneisses ri.ch in mica, with aplitoid muscov ite lcptynites, the layers being 0.3 to 3-4 m thick...... 48.0 4. Biotite or two-mica gneisses, medium-to fine-grained, locally with fine Augen struc- ture...... 20.5 3. Alternation of two-mica, biotite and muscovite gneisses and gneiss-schists, and thi n amphi boJite i nterlayers...... 28 .0 2. Amphibolites, fine- to medium-grained, massive or layered, in some layers with gar- net and epidote...... 62.0 I. Rich in mica (biotite and muscovite) gneisses to gneiss-schists, fine to medium-grai- ned...... 2G. O The total thickness of the Yailadzik Member in the section is 248.5 m. Sole. Arda Group, Belopole Formation: two-mica granitized gneisses and granite-gneis ses with interlayers of porphyroblas tic migmatites. Two complementary sections have been studied in the northern limb of the Kamil ski dol syncline for to characterize the member more completely. Complementary section I (fig. 1 II-II, and fig. 2, B). Consists of the packets 1 to 9 from the section of the Cepelare Formation which begins at the state border with Greece at 100m north of the height 545.5, and continues southeast along the ridge through the height 481.3 to the river Golemiya dol, and from there to the southeast along the road through the village Kamilski dol to the height 360.8. Cover. First packet of the Tumbata Member (packet 10 on fi g. 28) with a fa st lithologic transition: layered, locally massive amphibolites with rare small bodies and lenses of eclogites. Description of the section: Thickness , m 9. Fine-grained biotite gneisses interlayered with amphibolites, garnet micaschists and hornblende gneisses...... • . . . 22 .8 8. Medium-grained muscovite gneisses, locally with fine Augen structure...... 31.0 7. Fine-grained biotite gneisses, in some interlayers with muscovite and ga rnet . . . 32.0 6. Aplitoid muscovite leptynites with layer-parallel quartz veins...... 4.8 5. AI ternation of two-mica gneisses and gneiss-schi ts with a pi iloi c1 muscovite leptyni tes (layers 0.5 to 4-5 m thick)...... 43 .0 4. Biotite to two-mica gneisses, with fine Augen structure ...... 18 .0 3. Alternation of two-mica, biotite and muscovite gneisses and gneiss-schists with fine- l ayered amphibolites...... 37.0 2. Fine- to medium-grained amphibolites, massive or layered, in some layers with gar- net and epidote ...... _ ...... 41.0 I. Fine- to medium-grained, mainly two-mica or locally muscovi te gneisses and gneiss- schists...... 28.0 Total thickness of the section 256.8 m. Sole. Arda Group, Belopole Forma tion: medi um-grained two-mica banded granitized gneisses of granite-gneisses . Complementary section II (fig. 1, III-III; fig. 2C). Covers the packets 1 to 7 from the section of the Cepelare Formation which begins from the peak Papaztepe, follows south along the state border with Greece through the height 387. 6 to the right confluent of the river Cavdarlasko dere, and from there along the road south to the height 293.3. Cover. First packet of the Tumbata Member, with a sharp lithologic change: medium grained massive and layered amphibolites containing in some layers garnet and epidote (packet 8 from fi g. 2C) . Description of the section: Thickness, m 7. Medium-grained biotite to two-mica gnei sses, in some layers with ga rnet. 57.0 6. Alternation of two-mica, biotite and muscovite leptynites and two-mica schists (layers 0.2 to 8-10 m thick)...... 51 .0 5. Fine-grained bi otite to two-mica gneisses, in some layers ga rnet-bearing...... 15.5 4. Alternation of two-mica and muscovite gnei sses and gnei ss-schi sts with single layers of aplitoid muscovite leptynites and amphibolites 1 to 4-5 m thick...... 32.0 3. Two-mica (rich in mi ca) gnei sses and gneiss-schists with irregularly occurring garnet 16.0 2. Fine- to medium-grained amphibolites, massive or layered, locally with garnet and epi- 8 dole...... 86 .0 1. F i nc-g r ~ine d two- mica gneis ~ - sc hi s t s io gnei sses, fin ely layered, in some beds with ga rnet...... 30.0 The ic tal thi ckn ess of the section reaches 287.5 m. Sole. Arda Group, Belopolci Formation: hornblende io hornblende-biotite and biotite homeo blaslic granite-gneisses. The Yailadzik Member shows in its type area (with the three sections described) a lateral constancy in the sequence of the building packets and their composition, with a slight tendency towards increase of its thickness from west to east, and namely from 248 .5-256.8 to 287 .5 m in the easternmost outcrops. This constancy is preserved al so between the villages of Oresino and Gornoselci in the southern limb of the Kami !ski dol syncline (and northern periphery of the Bjala reka structure, respectively); to the west of this area the content of amphibolites in creases in the Yailadzik Member. This tendency is followed in three complementary sections as follows. Complementary section III (fig . I, IV-IV; fig. 3C). Covers the packets from I to 7 from the section of the Cepelare Formation which begins in the Aterenska River near the village of Gorno Kobilino, and follows along the road north to the peak Karakus, before the village Gornoselci. Cover. The Yailadzik Member is covered with a sharp lithologic boundary by the first packet of the Tumbata Member (packet 8 on fi g. 3C): fine-grained and fine-layered amphibolites interlayered with aplitoid leptynites. Description of th e section : Thickness, m 7. Fine-grained two-mica gneisses to gneiss-schists, ri ch in mica in some layers, with fine Augen structure...... 62 .0 6. Alternation between gneiss-schists, a mp hi halites and fine-grained two-mica gneisses (layers 2-3 m thick)...... 25.0 5. Fine-grained muscovite gneiss-schists and gneisses ri ch in mica ...... 54.0 4. Alternation of two-mica gneiss-schists, amphibolites and fine-grained two-mica gneis- ses (thickness of the layers from 0.10 to 2-3m)...... 40.0 3. Fine-grained muscovite to two-mica gneisses and gneiss-schi sts with interlayers of mus- covite gneisses with fine Augen structure...... 32.0 2. Fine-grained layered amphibolites, in some layers with garnet and epidote . . . . 25.0 I . Fine-grained muscovite or two-mica gneisses and gneiss-schists...... 25.0 Total thickness of the section 263 m. Sole. J\rda Group, Belopolci Formation: muscovite to two-mica banded granitized gneisses with large biotite flakes. The amount of am phi bolites increases in the packet 4 and 6 of the described sec tion; this tendency is stronger west towards the village of Popsko. Complementary section IV (fig . l, VIII-VIlle; fig. 3B). It contains the packets from 1 to 10 from the section of the Cepelare Formation which begins at 300m south of the farmyard of the village of Popsko and continues northwest along the road below the peak of Tepeto to the height 663 0 Cover. The first packet of the Tumbata Member (packet II of fig. 38): medium-grained, slightly migmatized amphibolites with small boudinaged bodies and lenses of metaserpentinites. Description of the section: Thickness, m !O o Two-mica gneisses to gneiss-schists, in some pl anes with coarse muscovite and garnet; thin interla yers of fine-grained poor in mica gneisses, and thin-layered amphibolites . . . . 20.0 9. Alternation of muscovite gneiss-s chi sts and fin e-grained muscovite and two-mi ca gneis- ses, and rarely a mphi halites .. 0 • • • • • • • • • • • • • • • • • • • • • • • • • • • • 15.0 8. Medium-grained, thinly layered amphiboliteso . 0 • • • • • • • • • • • • • • • • • • 12.0 9 7. Alternation of muscovite gneiss-schists, and line-grained muscovite and biotite gneis- ses, with unfrequent amphibolites...... 22.0 6. Fine-grained layered am phi boli tes...... · ...... 15.0 5. Finely layered muscoyite gneiss-schists to gneisses with thin (less than 2 rn) interlayers of arnphibolites...... 52.0 4. Fine-grained layered arnphibolites, locally with sli ght migmalizalion ...... 42.0 3. Muscovite gneisses to gneiss-schi sts, with thin (less than 0.30 rn) The amount ofamphibolites increases in thi s seticon gradually reaching upto 30% of the volume of the Y ai Ia dzi k Member. Complementary section V (fig. I, IX-IX; fig. 3 A). It comprises the packets from I to 10 in the section of the Cepelare Formation which begins at the road between the villages of Popsko and Starinsko, continues along the river Cairdere, passes through the height 797.5, and from there towards northwest along the road to Bubino, through the village, and along the path to Kalpak mahnla. Cover . Sharp lithologic bo undary with the first packet of the Tumbata '"\ember (packet 11 from fig. 3A): medium-grained layered amphibolites with slight layer-parallel migmatization, with bo dies and lenses of metaserpentinites in the upper parts . Description of the section: Thickness, m 10. Thinly layered two-mica gneisses with interbe ds of line-grained biotite gneisses, amphi bolites and aplitoid muscovite leptynites...... 34.0 9 . Alternation between muscovite gneiss-schi sts and fine-grained biotite gneisses and amphibolites containing layer-parallel migmatic pegmatoid veins (thickness less than 0.8 m) 18.0 8 . Amphibolites, rnedium-grainerl, layered, with a slight la yer-parallel migmatization . 10.0 7. Alternati on of muscovite gneiss-schists with line-grained muscovite a nd biotite gneis- ses and fine-layered amphibolites ...... 25.0 6. Amphibolites, medium-gra ined, layered ...... 18.0 5. Muscovite gneisses and gneiss-schists with thin amphibolite layers (less than I m) . 50.0 4. Fine-grained layered amphibolites ...... 45.0 3. Muscovite thinly-layered gneiss-schists a nd gneisses, with thin amphibolite layers .. 30.0 2. Thinly layered fine-grained arnphibolites; in the ba sal parts of the packet they alternate with fine-grained hornblende and biotite gneisses and aplitoid muscovite leptynites .. 40 .0 1. Fine-grained two-mica or muscovite gneiss-schi sts and schists, garnet-bearing along some foliation s urfaces, with interlayers of aplitoid muscovite lcptynites...... 30.0 The total thickness of the section is 300 m . Sole. Arda Group, Belopolci Forma lion: two-mi ca or muscovite banded grani ti zed gneisses. The amount of the amphibolites in this section increases to about 44% of the to tal rock volume. Characteristic features of the Y ailadiik Member: - The Member is built up mainly of fine- to medium-grained biotite or two-mica, rarely muscovite and hornblende gneisses which define its general characteristics. - Against the general gneissose background, differently thick interbeds of two mica and muscovite gneiss-schi sts, aplitoid muscovite leptynites, and amphibolites occur; they are irregularly distributed.and give a varied appearance to the unit. - The rocks of the Yailadzik Member are slightl y migmatized parallelly to the foliation in different parts of the section; layer-parallel or cross-curring mig matic pegmatoid veins (0.10 to 2m thick) are comparatively rarely observed. 10 Popsho -St Yani """'='"'- ~ .. CO l UM!Io c ~ i ~ u .. • .! . .. ~ • : ~·i ~ ~ :> "'0 CD I -~ ~ I ,.1-:::'" ~ \ I " Pcp s lc :> - Tep~t .., ~ ~-== \ 0 I 0 \ ~...... - - --= \ \ .. ~--~ \ "' " ~ ~ =:-:;: \ \ ~--...::=: ,, >: '' 1--Z::-z: 2:: ~- ~ ' " 0: .. " " ~-:~~ ""' ~~~ ",, " -~-~ -~ ~ ~ "'- " o " "~-=~~ 2014 -~~ 0 Kob il ino - Gor r:oset ci ·-· _. - -_ 17 10 \ ~~ }~ ~=-- -~::r:::- \ <( 1S19 \ ~~~ .. _J ._l \ ~_i~.:.¥' , .,,,~-~ I :l. f I} } .. \ I It S1~_.·=-~ I-- '- -· - --j \ I ~ -=- - ~ _i -"+-'-' j.~...:-=-:..~=:.·--=-=.... - - - -- ~ ,, 1-= ~ - --= - ---~ "f--=:-===== , ;:=-"'----;;.~ " :-.: - .: - .=-::. Fi g. 3. Compl emen tary sections of the Ce p e l a re~For m a ti o n (IV-IV, V- V and VI-V I from fi g. 1) 11 - The Yailadiik Member begins in all outcrops with a normal lower boundary with a packet of fine-grained predominant! y two-mica gneiss-schists and gneisses which contain rarely and in few outcrops garnet and kyanite. The rocks of this pa cket cover different stratigraphic levels of the Belopolci Formation of the Arda Group (Prarhodopian Supergroups) thus marking a geographic discordance irrespectively of the angular concordance between the rocks of the two lithostratigraphic units in the outcrops themselves. -The Yailadiik Member shows in the northern limb of the Kamilski-Dol syn cline a vertical and lateral steadyness, without considerable changes in the composi tion and sequence of the packets. - This character is valid also for the southern limb of the structure between the villages Oresino and Gornoselci; from the last locality westwards, a gradual increase of the amount of amphibolites is observed, and the Member obtains a more varied cha racter. The amp hi bol ites gradually reach an amount of about 30%, and up to 44% in the westmost section (fig. 3A). - The total thickness of the Yailadiik Member in the area studied varies bet ween 248.5 and 300m in the westernmost outcrops. Occurrence and regional importance. The rocks of the Yailadzik Member have a 1imi ted occurrence in the type region, and its importance for the other outcrops of the Cepelare Formation in the Rhodope Massif wi 11 be elucidated after a com plete revision of all outcrops . T u m b at a Me m b e r (TyM6eHCKH lJJJeH) (new member) It is introduced here for the first time. Named after the s ummit Tumbata (Ivaylovgrad area) where the type section is located. Historic notes . Before the present study. the rocks of the Tumbata Member have been included in the general composition of the "suite (formation) M;"' (YI B a HoB, 1961), in the "Proterozoic structural stage" (B o H 11 o B et al., 1963) and in the Ce pelare Formation (K o >K y x a p o B et al., 1985) . Composition. The Tumbata Member is bui It up in its type area dominant! y of two-mica, and more rarely, muscovite schists and gneiss-schists with garnet. The lat ter in some layers attains up to 1 em. The Member begins in all outcrops with a packet of amphibolites, and ends with a gneiss packet (fig. 2 A. B, C). Against this back ground of schists and gneiss-schists, different inter layers occur. They are bui It up of fine-grained biotite gneisses, aplitoid muscovite leptynites, calcareous schists, white medium-grained marbles, iron- and graphite-bearing quartzites, and thinly-layered amphibolites, the thickness varying between 0.1 and 7-8 m. Single crystals or accu mulations of kyanite occur in some layer with undistinct boundaries within the schists. The Tumbata Member is gradually enriched in amphibolites in the southern limb of the Kami !ski Dol syncline west of the village Gornoselci where the amount of the gneisses increases too (fig. 3 C). Thi s tendency becomes stronger southwest of Bubino, and the Tumbata Member becomes hardly distinguishable and is intefingering with the general alternation of the Cepelare Formation from the Avren syncline. Several sec tions have been chosen amongst the many sections studied for to demonstrate the la teral changes. Holostratotype (fig. 1, 1-1; fig . 2 A) . It comprises the packets from 7 to 14 in the general section of the Cepelare Formation which begins 500 m east of the summit Yailadzik, continues southeast along the road near the summits Kyucukkale and Sre barnica, and ends 250m southeast from the sheep-folds of the village Kamilski-Dol. Covtr. The Tumbata Membrr is covered with a sharp lithologic;:! change by t he rocks of the Kamildol Member (packet 15) : fine- to medium-grained amphibolites, thinly, layered, with garnet and epidote. 12 Description of the section: Thickness, m 14. ,\\cdium- lo fin e-grained muscovite a nd two-mica gnei sses wilh unfrequent lhin am phibolite layers ...... 56.0 13. Two-mica gneiss-schists and schi sts, mi gmatized parallelly to the layers, with some gar- net and kyanite...... 58 .5 12. Two-mica or musco vite schi sts containing single thin layers (0.3 to 1.5 m) of two-mica gneisses a nd gneiss-schists, a mphi bol ites, and iron· bearing graphite quartzites...... 87.5 II . Fine-grained quartzites with garnet, gra phite and single grains of magnetite, haema- ti te and p yrrhoti ne ...... 1.2 10. Two-mica schists with garnet, and rarely along some foliation surfaces with kyanite 12.0 9. White, medium-grained mar bles with gra phite...... 5.5 8. Two -mi ca to muscoyite schi sts with garnet, with thin (less than I m) interlayers of two- mica gneisses...... 36.5 7. Amphibolites: medi um- to fi ne-grained, massive or layered, with boudinaged eclogite bodies...... 33.5 The total thi ckness of the Tum ba ta Member in the type section is 290.7 m. Sole. Cepel are For mation , Yail adzi k lV\ ember (pa cket 6): fine-grained bi otite or two- mica gneis· ses, in some layers with garnet, and with fine-A ugen structure. In the other secti ons (fig. I, II-II, III-III; fig . 2, B, C) in the northern limb of the Kamilski Dol syncline, the Tumbata Member occurs in a similar manner, and will not be described here. The southern limb of the structure do not present conside rable differences in the composition and sequence of the packets up to the area of the vil lage Gornoselci; from that locality westwards, the amount of am phi bol ites and gneis ses increases gradually at the expense of the schi sts. Therefore, three complementary parallel sections have been studied. Complementary section I (fig. I, IV-IV; fig . 3 C). It comprises the packets from 8 to 12 from the section of the Cepelare For mation which begins from the village Ko bilino, and continues along the road to the summit Karakus before the village Gor noselci. Couer . The whole thickness of the Tumba ta Member does not crop out in this section because the rocks of the Member are covered by Paleog en e sediments in the area of the summit Karakus. Description of the section: Thickness, m 12 . Muscovite schists and gneiss·schi sts with interlayers of amphibolites and thinly layered muscovite gneisses...... 25.0 II . Fine-grained, thinly layered amphibolites...... 28.0 10. Thinly la yered two-mica schists and gneiss-schists, locally muscovitic and garnet bearing, with layer-parallel quartz and pegmatite veins; interlayers of amphibolites and quar- tzites in the upper parts of the packet...... 68 .0 8. Fine- to medium-grained amphibolites, layered, with interlayers of muscovite apli- toid leptynites...... 35.0 The total thickness of this incomplete section is 179 m. Sole. Yailadzik Member of the Cepelare Formation (packet 7) : fine-grained two-mica gneis ses, rich in mica, locally with fine Augen s tructure. Complementary section II (fig. I, IX-IX; fig. 3 A). It comprises the packets from 11 to 24 from the general section of the Cepelare Formation which be_gins on the road between the villages Popsko and Starinsko, follows along the river Cairdere through the height 797 .5, after that northwest along the road to the village Bubino, through the village and along the pathway to Kalpak Mahala . Description of th e section : Thickness, m 24. Fine-grained hornblende-biotite gneisses with thin amphibolite interlayers .. . _ 12.0 23. Fine-grained thinly-layered amphibolites...... 8.0 22. Fine- to medium-grained gneisses, hornblende-biotite to biotite, layer-parallelly migma tized, with layer-parall el or cross-cutting pegmatoid veins (up to I m thick). . 25.0 2 1. Fine-grained thinly-layered a mphibolites...... 18.0 20. Medi urn-grained hornblende gneisses...... _ ...... 6.0 13 19. Fine- to medium-grained, massive or layered amphibolites, with garnet and epidote 10.0 18 . .Medium-grained hornbl ende-bio tite to biotite gnei sses, with thin a mphibolite inter- layers ...... • ...... 18 . 0 17. Medi urn-grained I ayered a mp hi boli tes, a t the base of the packe t with massi\·e struc- ture...... 10.0 16. Fine- to medium-grained hornblende-biotite gneisses with interlayers (up to 2 m) of biotite gneisses and amphibolites, and two boudinaged interlayers (less than I m) of medium grained white marbles in the upper parts of the packet...... 26.0 15. Banded la yered amphibolites, in the upper parts of the packet in tr(lnsition to hornblen- de gneisses with garnet, with s li ght migmati zati on ...... 19.0 14. Two-mi ca or muscovite gneiss-schists to gneisses, in the upper parts of the packet with interlayers (2m) of amphibolites, hornblende gneisses, aplitoid leptynites a nd two-mica schists 52.0 13. Coarse-grained amphi bol i les with garnet...... 18 .0 12. Two-mica or muscovite gneiss-schi sts to schi sts, with thin a mphibolite interlayers 51.0 II. Layered amphibolites, with slight layer-parall el mi gma ti za ti on, and s mall (0 . 1 m) layer-parallel serpentinite bodies...... 28.0 The total thickness of the Tumba ta Member in the section is 301 m . Sole. Yailadzik 1\\ember of the Cepelare Forma ti on (packet 10): thi nly layered two-mi ca gneis ses to gneiss-schists with interlayers of fine-grai ned bi otite gneisses, a mphi bo lites and aplitoid mus covite leptynites. The gradually increasing amount of the amphibolites reaches in this section its maximum (about 40% of the total volume of the Tumbata Member) . Principal features of the Tumbata Member: - In its type area, the Tumbata Member is bui It up of typical two-mica, rarely muscovite schists to gneiss-schists, garnet-bearing, in some layers also kyanite-bearing. - Within the whole section, amongst the schists and gneiss-schists, thin inter layers are observed; they are built up of fine-grained biotite, two-mica and hornblende biotite gneisses, amphibolites, marbles , calcareous schists, rarely aplitoid muscovite gneisses and quartzites with magnetite and graphite. - The Tumbata Member begins in all exposures with a normal lower boundary of medium-grained massive or layered amphibolites which contain eclogite bodies , and ends with a gneiss packet which is built up in different sections of biotite, two-mica or hornblende-biotite gneisses. The rocks of the Tumbata Member are slightly layer-parallely migmatized in dif ferent areas; the migratization affects usually the gneisses and amphibolites, and un frequentl y the gneiss-schists. - Layer-parallel or cross-cutting migmatic pegmatoid veins or veins of milky white quartz occur in the rocks of the Member. - The Tumbata Member is steady and constant in vertical and lateral directions in the northern limb of the Kamilski Dol syncline, without substantial changes in the composition and sequence of the individual packets. This character is preserved also in the southern limb of the syncline up to the area of the village Gornoselci; from that locality westwards, the content of the different rock varieties gradually changes. -The amphibolite amount behJ.;een the villages Gornoselci and Bubino gradually increases at the expense of the schi sts and gneiss-schists, and reaches up to 40% of the total volume of the Member. The amount of the gneisses (hornblende or hornblende biotite) also increases in that area. - The total thickness of the Tumbata Member varies from 290 to 308 m. Distribution and regional importance. The rocks of the Tumbata Member are wide spread in their type area but its importance for the other outcrops of the Cepe! are For mation in the Rhodope Massif will be elucidated during the forthcoming revisions. K a m i I s k i d o I M e m b e r (KaMHJJ)I.OJICKH tJJieH) (new Member) It is introduced herewith for the first time. Named after the village of Kamilski dol, Ivaylovgrad area, where the holostratotype and the most representative exposures have been observed. 14 Historical notes. The rocks of the Kamilskidol Member have not been set apart as an independent lithostrati graphi c unit up to nov.·. They have been treated as a part of the "lower metamorphi c ser ies - suite (formati on) A\"]" (VI BaH o B, 1961), the ''Proterozoic structural stage" (E o H HoB et a! ., 1963), and the Cepelare Forma tion of the Rhodopian Supergroup (K o )!{ y x a p o B et a!., 1985). Composition . The Kamilskidol Member is built up of various medium- to fine grained, massive or layered amphibolites, with or without garnet and epidote. At this general background, interlayers or packets of different thickness are observed. They are built up of muscovite, two-mica and biotite gneisses, gneiss-schists and schists, white medium-grained marbles, calcar eous schists and calciphyres (regional-metamor phic skarns), aplitoid muscovite and biotite leptynites , hornblende gneisses , and iron bearing and graphite-bearing quartzites . The numerous sma ll bodies and lenses of me tamorphosed ultrabas ic rocks, and less fr equentl y, eclogites, are also an integral part of the Member. · This is the complete characteristics for the Member in the northern I imb of the Kamilski Dol syncline, where the cover of the Member is missing. In the topmost parts of the Member in the area between the villages Popsko and Bubino, interlayers of marbles occur parallelly with the increasing amount of packets enriched in gneiss schists and schists. Holostratotype (fig. 1, I-I; fig. 2 A). It comprises the packets from 15 to 25 from the general section of the Cepelare Formation which begins at 500 m east of the summit Yailadzik, continues through the summit to the southeast along the road near the summits Kyucukkale and Srebarnica, and ends at 250 m southeast of the sheep folds of the village Kami !ski Dol. Cover. Although represented by almos t lhe full secti on in the centricline of the Kamilski Dol syncline, here the cover of the Cepelare Formation, and of th e Kamilskidol Member, is mi ssing. Description of the section : Thickness, m 25. Alterna tion of layers with different thickness of a mphiboliles (predominant) with va- rious micaschists, aplitoid leptynites and hornbl ende gneisses, with bodies and lenses of metamor phosed ultrabasic rocks...... 48 .0 24. Two-mica schists and gneiss-schi sts, locally with ga rnet, with interl ayers of amphiboli - tes, muscovite aplitoid leptynites and iron -bearing quartzites...... 36. 5 23. Medium-grained layered or massive a mphiboli tes, locally with garnet, epidote and mag netite, with interlayers (0 .5 to 7-8 m) of muscovite aplitoid leptynites, two-mi ca a nd musco vite schists and gneiss-schi s ts, iron- bearing quartzites, and di fferen t in size bodies and lenses of metamorphosed ultra basic rocks a nd actinolite-chlorite rocks...... 182.0 22. Two-mica gneiss-schi sts with garnet, kyanite and hornblende. . . 40.0 21. Thinly layered muscovite gneiss-schi sts ...... 5.0 20. Medi urn-grained white marbl es...... 1.0 19. Medi urn- to fine-grained amp hi bol ites with garnet...... 15.0 18. Medium-grained while marbles...... 1.5 17. Medium-grained thickly-layered a mphibolites . . . _ ...... 30.5 16. Medium-grained white marbles with garnet, phlogopite and pyrite...... 25.0 15. Thinly-layered amphibolites, along some foliation surfaces with garnet and epidote 10.5 Total thickness of the Member in the holotype (without exposed cover) 395 m. Sole. Tumbata Member (p acket 14) : medium- to fine-grained muscovite and two-mica gneisses with amphibolite interlayers. The Kami !ski dol Member is represented in the northern I imb of the Kami !ski Dol syncline with an almost complete section. However, some differencies are obser ved in the sequence of the packets, and some changes in their thickness occur late rally from west to east. Two complementary sections are described for a more complete characteristics. Complementary section I (fig . I, II-II; fig. 2 B) . It comprises the packets from 20 to 32 from the section of the Cepelare Formation which begins at the state border 15 with Greece, passes through the height 545:5, continues southeast through the height 481.3 to the river Golemiya Dol, and from there southeast along the road through the village Kami !ski Dol to the height 360.8. Cover. Missing in the centricline of the Karnilski Dol syncline. Description of the sect ion: Thickness, rn 32. Layered or massive arnphibolites, locally with epidote garnet and magnetite, and numerous layer-parallel or cross-cutting pegrnatoid veins with muscovite, two-mica hornblende and biotite gneisses (2-8m thick), and iron-bearing quartzites (0.2-1.5 m thick); the amphibo lites contain bodies and lenses of different size built up of rnetarnorphised ultrabasic rocks, ac- tinolite and chlorite schists...... 180.0 31. Medium-grained muscovite and two-mica schists and gneiss-schists, locally with gar· net and kyanite...... 28.0 30. Layered am phi bol ites with epidote...... 8.6 29. Medi urn-grained white marbles...... 4.2 28. Layered medi urn-grained amp hi bol i tes...... 4.4 27. Muscovite gneiss-schists to schists with layer-parallel migrnatic pegrnatoid veins . 16.0 26. Alternation between arnphibolites, and two-mica schists to gneiss-schists...... 62.0 25. Medium-grained white marbles with hornblende and magnetite along the foliation sur- faces...... 42.0 24. Alternation between two-mica gneiss-schists and gray-white marbles 3-5 ern thick . . 3.4 23. Medi urn-grained muscovite gneisses with a single amp hi boli te I ayer (5 ern). . . 6.4 22. Layered medi urn-grained amp hi bol ites...... 3.8 21. Medi urn-grained muscovite gneisses...... 8.3 20. Layered medi urn-grained am phi bolites...... 28.0 The total thickness of the Karnilskidol Member in this section is 395.1 rn. Sole. Turnbata Member (packet 19): medium-grained hornblende gneisses . Complementary section II (fig. I, III-III; fig . 2 B). It comprises the packets from 13 to 16 from the section of the Cepelare Formation which begins at the summit of Papaztepe, continues south along the state border with Greece through the height 387.6 to the right confluent of the river Cavdarlasko Dere, and from there along the road southwards to the height 293.3 . Cover. Missing in the centricline of the Karnilski Dol syncline. Description of the section: Thickness, rn 16. Massive or layered arnphibolites, in some layers with garnet, epidote, and single mag netite grains. Within the whole section, they contain irregularly distributed interlayers of mus covite, two-rni ca and biotite gneisses and gneiss-schists, muscovite apli toi d leptyni tes (0.5 to 6-7 rn), and different in size layer-parallel bodies and lenses of metamorphosed ultra basic rocks, actinolite and talc-chlorite rocks...... 250.0 15. Alternation of arnphibolites, muscovite and two-mica gneisses, gneiss-schists and schists, and two interlayers of calcareous schists (less than 0.5 rn), with predominance of am phi bolites . 59.0 14. Medium-grained white marbles with graphite and muscovite, in some layers with phlo- gopi te...... 83.5 13. Layered medium-grained arnphibolites interlayered at different levels with musco- vite gneisses, hornblende gneisses and aplitoid muscovite leptynites (to 4 rn)...... 48.0 Thickness of the Member in this section 440.5 rn. Sole. Tumbata Member (packet 12): fine-grained thinly-layered two-mica gneisses with thin interlayers of arnphibolites and muscovite schists. The rocks of the Kami !ski dol Member are represented in a similar manner also in the southern limb of the Kamilski Dol syncline up to the area of the village Gorno selci. In the area of Cuculigovo they are disrupted by the granite intrusion. North of Popsko and west of Bubino, although with a strongly faulted lower boundary, the Member has a normal upper boundary observed in the next two complementary sec tions. Complementary section III (fig. I, VIII-VIlle; fig. 3 B). It comprises the packets 16 rom 13 to 25 from the section of the Cepelare Formation which begins at 300m south of the farmyard of the village Popsko , and continues northwest along the road beneath the height Tepeto to the height 663. Cover. The Ka milskidol Member is covered with a normal concordant boundary by the first pa· cket of the Bogutevo Formation: medium-grained biotite gneisses, layer-parallelly migma ti zed, with interlayers of porphyroblastic migmatites. Description of th e section: Thickness, m 25. Fine-grained hornbl ende, hornblende-biotite and biotite gneisses .. . .. 20.0 24. Medium-g rained \\:hite marbles ...... 10.0 23 . Medium-grained layer-parallel mi gmati zed and dioritized amphibolites ...... 40.0 22. Medium-g rained white marbles ...... 3.5 21. Alternation of layer-parallelly migmatized biotite gneisses a nd amp hibolites with metaultrabasic bodies...... 21.0 20. Medium-grained layered a m phibol ites with bodies of metaultrabasic rocks and actino- 1 itic roc ks ...... _ ...... 18.0 19. Schistified s potty serpentinites, a mphi bolized al ong fra ctures...... 10.0 18. AI ternation of layer-parallely migmati zed bioti te gneisses and a mp hi bol ites with s mall ultra basic bodies...... • ...... 40.0 17. Banded medium-grained and l ayer-parallelly migmatized amphi bolites with ultraba- sic bodies...... 31.0 16. AI ternati on of fine- and medi urn-g rained biotite and hornblende-biotite gneisses and am- phi bol ites, layer-parallel! y mi g rn a ti zed, with layer-parallel mig rna tic peg rn a toi d veins • . . 38.0 15. Banded or massive amphibolites with s mall boudinaged bodies of metaultrabasic rocks 31.0 14 . Fine-grained muscovite to two-mica gneisses, locally mi gmatized parallelly to the fo liation, with layer-parallel or cross-cutting migmalic pegmatoid veins...... 42.0 13. Fine-grained layered amphibolites with interlayers of fine-grained hornblende-bio- tite gnei sses...... 28.0 The thi c kness of the exposed part of the Kamilskidol Member in thi s section reaches 332.5 m. Sole. Not exposed: tectonic boundary (fault) with the rocks of the Tumba ta Member. Complementary section IV (fig_. l, IX-IX; fig. 3 A) . It embraces the packets from 25 to 27 from the section of the Cepelare Formation which begins on the road between the vi llages Popsko and Starinsko, follows the river Cairdere, passes through the height 797.5, and from there to northwest along the road through the village Bubino, and con tinues along the pathway to Kalpak Mahala. Cover. Bogutevo Formation: medium-grained biotite layer-parallel migmatized gneisses. Description of the section : Thickness, m 29. Massive or layered medium-grained amphibolites with or without garnet and epidote, predominant in the pa ~.: ket but containing interlayers in a frequent alterna ti on, of mi caschi sts, muscovite aplitoid leptyniles, iron-bearing quartzites, and one mar ble interlayer 2.4 m thick, with bod ies (different in size) of mela ultrabasic rocks...... 86.0 28. Medium-grained massive or layered a mphi boliles with unfrequent interlayers of garnet micaschists, one marble interlayer 1. 8 m thick, and s ignl e bodies and lenses of meta ultrabasic and actina I ite-chlor ite rocks...... 90.0 27. Medi urn- to fine-grained layered a m phi bolites with unfrequen t interlayers of muscovite aplitoid lep tynites, garnet micaschists and quartzi tes with magnetite and gra phi te...... 52 .0 26. Alterna tion of amphibolites and micasc hi sts to gneiss-schi sts (l ayer thickness from 0.5-1 to 8-10 m) ...... • ...... 25.0 Tectonic con tact (f a ult) with packet 25. 25. Medium-grained layered amphibolities with thin interlayers of sli ghtly mi gma tized biotite a nd horn blende gneisses...... 22.0 Total thickness of the incomplete section: 275 m . Sole. Tumba ta Member (p acket 24) : hornblende-biotite medium- to fine-grained gneisses with amphibolite interlayers. In the southern part of the area studied, outside the Kamilski Dol syncline, the rocks of the Kami lskidol Member are in an allochthonous position as a part of the Pelevun 2 Geologica Balcani ca, 22.3 17 thrust sheet. The first packets of the Member, including the marbles thick up to 80 m, participate in this thrust shee.t. Characterisitc features of the Kamilskidol Member - In its type area, the Kamilskidol Member is built up of various medium to fine-grained, massive or layered amphibolites, in some layers with garnet and epi dote. - Against this general amp hi bol ite background, inter layers of packets occur which are built up of various micaschists, gneiss-schists and gneisses (muscovite, bio tite, two-mica, hornblende etc.), aplitoid muscovite and biotite leptynites, marbles, calcareous schists, calciphyres, iron- and graphite-bearing quartzites. - All levels of the Kami !ski dol Member contain different in size bodies and len ses from metamorphosed ultrabasic rocks, actinolite and actinolite-chlorite rocks and eclogites. The dimensions of the bodies, as well as their relative amount are increasing in the middle and upper parts of the Member. - Amphibolites, gneisses, and locally the gneiss-schists are slightly migmatized parallelly to the layers, and obtain the structural features of fine stromatitic migmati tes. - All rocks of the Kami !ski dol Member contain I ayer-parallel or cross-cutting migmatic pegmatoid veins up to several metres thick. In the centricline of the Ka milski syncline they form pegmatite fields which have been mined for muscovite. - The interlayering rock varieties increase in amount amongst the am phi boli tes in the upper parts of the Member from east to west; thus the upper parts of the Mem ber obtain a varied character. -The total thickness of the Kamilskidol Member reaches 440 min its type area. The complete characteristics of the Cepelare Formation in the Ivaylovgrad and Krumovgrad areas is given by the description of the constituent members. It differs from the other outcrops in the Rhodope Massif by the considerably greater partici pation of metamorphosed ultrabasics, the clear distinction between the three members, and the increased thickness which reaches up to 1000 m . Bogutevo Plagiogneiss Formation It was formally introduced in the nomenclature by K o )!{ y x a p o s (1984) with a type area in theCentral RhodopeMountains where the holotype was described. In the pre sent region, the Bogutevo Formation is distinguished for the first time with this study, and its occurrence is shown on a geological map. These outcrops are loca lized in the northwestern part of the map (fig. 5) between the villages Bubino, Cer ni cino and Kozoukharci. They continue to the south as separate blocks covered by the Paleogene sediments, through Kazaltepe and the village Cala, and southwest of the vil lage Bagrilci join the rocks of the Bogutevo Formation of the Avren sync! ine (K o )!{ y - xapos, 1987). The Bogutevo Formation is built up mainly of medium-grained biotite, and less frequently hornblende, hornblende-biotite or two-mica plagioclase gneisses. In some packets they contain garnet. Against the general gneiss background of the Formation, thin interlayers are observed: medium-grained white marbles with graphite and phlo gopite, thinly layered fine-grained amphibolites, medium-grained massive amphibo lites and often preserved in boudinage structures, and two-mica gneiss-schists to schists. All rocks of the Formation are irregularly affected by migmatization being changed in separate outcrops or packets into layer-parallel banded, banded-porphyroblastic or porphyroblastic migmatites. In the less atteined by migmatization gneisses often layer parallel or cross-cutting migmatic pegmatoid veins are observed. The sequence of the rocks in the Formation and the constituent packets is followed in two reference sec tions. 18 Reference section I (fig. 1, VIIJe-VJIIb; fig. 4). It contains the packets l to 7 from the joint section of the Bogutevo and Vaca Formations which begins at 600 m from the summit Tepeto (2 km NNW of the village Popsko), continues along the same ridge through the height 663 .0 to the watermill in the Kulidzikska River, and from there northwards along the pathway to the ridge of Karaburak. Cot•a. V al:a Formation (packet 8): concordantly sit uated fine-grained biotite gneisses to gnei ss schists. Description of the section: Thi ckness, m 7 . .M edium-grai ned biotite gneisses, locally with hornblende, irregul arly migmatized parallel! y to the foliation ...... 70.0 6. Medium-grained wl(ite marbles with graphite and phlogopite ...... 18.0 5. Alternation of medium- to fine-grained biotite gnei sses and thinly-layered fine-grained amphibolites...... 36.5 4 ..Medi urn- to fine-grained biotite hornblende-bearing gneisses in con tact with amp hi bo- 1 ites (up to 1 m) ...... 45.0 3. Medium-grained layered amphi bolites with s li ght layer-parallel migmatization. . . . 8.0 2. Biotite gneisses, loca lly with hornblende, migmati zed parallelly to the layers, with in terlayers and boudinaged bodi es of amphibolites and metaultrabasics (0.3 to 5-6 m thick), and packets from medi urn- to coarse-porphyroblastic migmatites (8- 10 m thi ck)...... The boundary between the packets 1 and 2 is a vertical normal fault with hydrotherma l altera tions; the width of the cataclastic zone is about 10m. I. Medium-grained biotite gneisses, with slight layer-parallel mi gmatization, cross-cut by migmatic pegmatoid veins...... 78.0 The total (but incomplete) thickness of the Formation in this section is 272 m. Sole. Cepelare F ormation, Kamilskidol Member (p acket 25): fine-grained hornblende-biotite, hornblende and biotite gneisses. Reference section II (fig. I, VII-VIle; fig. 4). It contains the packets from 1 to 9 in the common section of the Bogutevo and Vaca Formations which begins on the road to the village Cernicino at 200 m before the sharp curve at the height 630.8, continues through the village, and ends at 350m north of the latter. Cover. Vaca Formation (packet 10 of the same section): two-mica garnet-bearing gneiss-schists, with normal concordant position of the layers. Description of the section: Thickness, m 9. Medi urn-grained biotite gneisses, in some packets with slight I ayer-paral lel rni gmati - zation...... 55.0 8. Fine-grained biotite gneisses...... 12.0 7. Medium-grained white marbles with graphite...... 24.5 6 . .Medium-grai ned biotite garnet- bearing gneisses i ntersecled by pegma toi d veins related to the Cucul igovo granites...... 16.0 5. Thinly-layered, medium- to fine-grained amphibolites...... 4.0 4. Medium-grained biotite gneisses, rich in mica, with a slight l ayer-parallel migmati- zation...... 24.0 3. Medium-grained thickly-layered amphibolites with a slight layer-parallel mi gma ti- zation...... 28.0 2. Medium-grained biotite gneisses with slight layer-parallel mi gmatization, and with am phibolite interlayers...... • ...... 52.0 1. Medium-grained biotite garnet-bearing gneisses, with a slight layer-parallel mi g matization...... 16.0 The incomplete thickness of the Formation in the section reaches 23 1 m. Sole. Missing in the section . The boundary with the Cuculigovo granites is a \Vide cataclstic zone related to a fault with slight hydrothermal alteration. The characteristic features of the Formation to the west of the reference sections described (in the vicinity of the village Padalo and so uth of it) do not deviate con siderably from the characteristics made (K o iK y x a p o s, 1984) for the Formation in the type area. The relative amount of the amp hi bol ites is here smaller than in the out- 19 ~ 0 ~:-.:~" ·-, · . ·) ?" ~ ~ · o Sofia ,J C1 L.....:...... :Jz L_2:__]J rLl-5 ~~6 Haskovo "'-.,. 0 ("·"""·J-oi·J •H· ~~· ~ ~ r/A ~ ~~~ ~~7 ~8 b:~9 ~~ o ~''L~I2 1---:;71 IJ5=I 2 I 0 I 2 )km f _,_-<>-_,JlJ Fll ,~. ~ 15 L..:::::._j /6 crops within the A vren syncline (K om y x a p o B, 1987), and corresponds to that in the type area. The total thickness of the Bogutevo Formation outside the reference sections rea ches up to 500 m (almost all sections are discontinuous). Vaca Varied Formation ThisFormation is introduced by Ko:il Cover. Mi ssing in the section: tectonic contact with Paleogene sediments and volcanics along the steeply dipping to the north Cernicino fault. Description of the section: Thickness, m 17. Medium-grained biotite gneisses with thin (less than 0.5 m) interlayers of amphibo lites and two-mi ca schists containing layer-parallel or cross-culling mi gmali c pegmatoid veins 158.0 IG. Fine-grained biotite g neisses with thin interlayers of two-mica gneiss-schists with gar net and kyani te...... 12.5 14 . Metaultrabasic rocks (serpentinites), schistified and intersected by chrysotile-asbes- tous veins (2-5 em)...... 180.0 14. Medi urn-grained layered a mphi bol ites. . . . 28.0 13 . Medi urn-grained gray calcareous schi sts. . . . . 2.8 12. Medi um-gr.:i ned white marbles with gra phite .... . 15.0 II. Metaullrabasics (serpenitinites), schistified ...... 128.0 I 0 . Two- mica gneiss-schi sis to gneisses wi lh game!. ... . 32.0 Fig . 4. Geological map of the lvaylovgrad part of the East Rhodope Mts 1 - Quaternary, and wa ter-covered areas; 2 - Pliocene sediments, Paleogene sediments and vol canics; 3 - Upper Cretaceous (?) granitoids (Rozino and Cuculigovo): 4-11 - Rhodopian Super group: 4 - metamorphosed ullrabasics. 5 - amphibolite packets with strati graphic significance, 6 - marbles in al l formations. 7 - Vaca Varied Formation, 8 - Bog utevo Plagiogneiss Formation; 9-11 - - Cepe/are Fcrn:ation: 9 - Kamilskidol Meml>er. 10 - Tumbata Member, 11 - Yailad zik Member; 12-13 ·-- Prarhodopian Supergroup: 12 - Belopolct Forma tion (of granitized gneisses and granite-gneisses), 13 - Tintja\'3 Granite-g11eiss Form ~ ticn; 14 - Pelcv un Thrust; 15 - faults ; 16 - s trike and dip of the foli a tion 21 The incompl ete thickness of the Formati on within th e section together with the thick met Reference section II (fig. 1, VJII b·VIIIc; fig . 4) . It comprises the packets fr om 8 to 12 from the common section of the Bogutevo and Vaca Formations w·hich begins at 600 m northwest from the summit Tepeto, continues along the same ridge through the height 663.0 near to the watermill in the Kulidzikska River, and from there along the pathway northwards to the ridge of Karadurak. Cover. Not exposed : intrusive contact of fine-grained leucocra ti c gra nites of the Cuc uli goyo type . Description of the section: Thickness, m 12. Fine- to medium-grained biotite gneisses with thin inlerl ayers of a mphi bo \iles and two- mica schi sts, and one interlayer (0 .8 m) of garnet-kyanite schists...... 87.0 II. Medi urn-grained thick\ y la yered am phi bot ites, locall y enriched in garnet along some foliati on s urfaces...... 37.0 10. Medium-grained gray ca lcareous schists rich in mi ca...... 8 .0 9. Medi urn-g rained white marbles with graphite...... 22 .0 8 . Fine-grained bi otite and two- mica gneiss-schists to gneisses, in some layers garnet- bearing...... 38.0 The thi ckn ess of the Vaca Forma ti on in this incomplete section reaches 192 m. Sole. Bogutevo Formation (packet 7): medium-grained biotite gneisses, migmatized parallclly to the foliati on , locally hornbl ende-bearing. The absence of a complete section of the Vaca Formation in the area studied is hampering a full comparison with its sections in the type area and in the Avren syn cline. The thickness of the incomplete sections reaches up to 600 m. and the exposed parts of the sequence have the same features as the sections of the V aca Formation in the areas mentioned. Characteristics of the Rupcos Group Lithostratigraphic features In the Ivaylovgrad and Krumovgrad parts of the East Rhodope Mountains the Rupcos Grou_p is represented by all its three formations known from the type area, and namely : the Cepelare Varied Formation, Bogutevo Plagiogneiss Formation, and Vaca Varied Formation. The Bogutevo and Vaca Formations have incomplete sections in the area studied. However, their composition and general features fully coincide with the holotype sec tions; the only difference is the increased amount of the metaultrabasic bodies, as well as their bigger dimensions. The Cepelare Formation is subdivided. at the background of the generally varied composition , in three clearly di stinguishable members: Yailadzik Member (predomi nantly gneissic), Tumbata .Member (mainly schistose), and Kamilslddol .Member (main ly amphibolitic). The three members are gradually enriched in amphibolites from the east to the west and southwest , and gradually interfinger with the common alternation of the rock varieties of the Cepel are Formation from the Avren syncline. All rocks of the Rupcos Group underwent a slight migmatization which develo ped parallelly to the foliation in the Cepelare and Bogutevo Formations, with forma tion of thinly-banded, banded, and locally porphyroblastic migmatites. In the middle and upper parts of the group, layer-parallel and cross-cutting migmatic pegmatoid veins occur, sometimes densely situated, which form "pegmatitic fields" mined for muscovite in the past. The total thickness of the Rupcos Group reaches 2100 m even with the incomplete sections of the Bogutevo and Vaca Formations. 22 The Rup cos Group overlies here too the rocks of the Prarhodopian Supergroup represented by the Arda Group (Belopole Formation). The Cepelare Formation with its first (Yailadzik) Member covers consecutively different stratigraphic levels of the Belopole Formation, thus outlining a clear geographic discordance between the Rho· dopian and Prarhodopian Supergroups in the peripheral parts of the Danailovo and Ze lezino dome-anticlines, and in the Konnik syncline. The Sitovo Group which covers the Rupcos Group in the type area, is absent in the East Rhodope Mountains, a fact already commented at (K o .>K y x a p o B, 1987). Metamorphism of the Rupcros Group The rocks of the Rupcos Group represent now a pol ymetamorphic product. It is are sult of multiphase superposition of different in t ype and intensity metamorphic events related with the Precambrian and the Phanerozoic megacycles. It should be emphasi zed, however, that the Precambrian metamorphic processes had formed the rocks with their most characteristic features, and all subsequent processes had a limited impor tance, and had not sub stantially di srupt the Precambrian metamorphic consolidation of the rocks and the related str.uctures. With the exception of the low-temperature hydrothermal metamorphism (serpen tinization) and of the early high-baric metamorphism proven for the metabasic rocks and the eclogites (K o .>K y x a p o B, 1984), all other rocks of the Rupcos Group under went different in time and intensity metamorphic changes in the following order: 1. Regional Precambrian metamorphism in amphibolite facies (Upper Riphean - Vendian), or principal regional metamorphism (after K o .>K y x a p o B a, 1984). The pre-metamorphic stage was characterized by the deposition of the primary sedi ments and manifestations of basic to ultrabasic igneous activity. The problem whether the rocks of the Rupcos Group underwent an earlyregional greenschist facies metamor phism (before the regional metamorphism in am phi boJite facies) which could cause the serpentinization of the ultrabasic rocks (K o .>K y x a p o B a , 1987) or these (together with the eclogites) were the two initial episodes of the general path of the regional me tamorphism. remains unsolved up to now. The rocks of the Rupcos Group are referred to the intermediate-baric series of mo derate pressure (type Barrow) and the amp hi bol itic fa cial group (Zwart et a!., 1967). The t ypical mineral associations for the different rock varieties are as follows : In the quartz-feldspar rocks : - plagioclase (ol igoclase) + quartz+ biotite±microcline ±garnet ±graphite; - plagioclase (oligoclase to oligoclase-andesine) + quartz+ hornblende±biotite garnet; - plagioclase (o 1igocl ase) + quartz+ muscovite± biotite; - plagioclase (oligoclase to albite-oligoclase)+ quartz±microcline + muscovite± biotite±garn et (in the leptynites); - plagioclase (oligoclase) + quartz+ biotite; In pelitic rocks : - plagioclase (oligoclase) + quartz+ biotite+ muscovite+ garnet; plagioclase (ol igoclase)+ quartz+ biotite+ graphi te; - plagioclase (oligoclase) + quartz+ muscovite±garnet; - plagioclase (ol igocl as e) + quartz+ muscov ite+ biotite+ kyani te+ garnet + gr a- phite; - quartz+ biotite+ muscovite±garnet ± graphite. In the silicic rocks (iron- and graphite-bearing quartzites): - quartz+ magneti te± haematite± pyrrhotine±chalcopyrite±pyr ite; - quartz+magnetite±h aematite±garnet; 23 - quartz+graphite±garnet; - quartz±magnetite±graphite+ garnet. In the basic rocks: - plagioclase (andesine to andesine-labradorite) -+- hornblende±garnet ; - plagioclase (andesine) + hornblende±quartz; - plagioclase (andesine) + hornblende+ epidote±pyroxene; - plagioclase (andesine) + hornblende ±biotite± quartz. These mineral associations are present in th e layered amphibolites which have derived from volcano-sedimentary protoliths; the typical orthoamphibolites formed after basic and ultrabasic igneous rocks, and the eclogites, have been throughly stu died by K o .>K y x a p o a a (1984 , 1985) who has described their metamorphic alte rations. In carbona tic rocks: - calcite+ hornblende+ graphi te; - calcite±plagioclase±quartz±phlogopite±grap hi te ; - calcite+diopside+quartz±graphi te. 2. Regional Precambrian migmatization (Upper Riphean - Vendian). This mi g matization affects on I y the rocks of the Rupcos Group and is a result of an in ternal redistribution of the salic components inside the Group. The migmatization in the lower parts (Cepelare and Bogutevo Formations) occurs as a layer-parallel mobi lization of the salic components which results in structural features of finely-banded, banded-Augen of porphyroblastic layer-parallel migmatites. In the upper parts of the Group (Vaca Formation) the layer-parallel migmatiza tion is slight or absent but the salic mobilizates from tbe lower levels have pene trated as cross-cutting and layer-parall el migmatic pegmatoid veins with a thickness of 0.2 to 2-3 m, locally containing coarse muscovite. Recrystallization of the regional-metamorphic minerals occurred in the different rock varieties during the migmatization, and was expressed in eli fferent manner, and namely: -in the quartzo-feldspathic rocks: as layer-parallel migmatization and graniti zation of the gneisses with formation of a second plagioclase generation (albite-oligo clase to oligoclase), microcline, and formation of a coarser mica including red-brown biotite; - in the basic rocks- layered and bed-like amphibolites, - the hornblende and epidote recrystallized in coarser grains, and during a regular dioritization, quartz felspathic segregations formed into the amphibolites with development of a spotty leopard structure, alterati on of rutile (if present) into titanite; the magnetite grains became coarser and form ed nest-! ike aggregates; the potassium metasomatosis related to the migmatization led to the formation of biotite after hornblende; - in the iron-bearing quartzites: second generations of quartz, magnetite and gar net have developed, and the graphite is increasing its dimensions; - in the carbonatic rocks: depending on the intensity of the migmatization pro cesses, regional-metamorphic skarns - calciphyres, developed, with a slight to mode rate or complete replacement of the marbles; sometimes as a resul t of this process, mono mineral garnet (granatite), epidote (epidotite) and diopside (diopsidite) rocks were formed; the typical mineral associations for the calci phyres are: calci te + pl agiocl ase+q uartz+ hornblen de + epi dote ± graphite; calci te+ quartz+ garnet + diopside+skapol ite; calci te+ garnet + specular ite; cal cite+diopside+garnet + magnetite. 3. Regional diaphthoresis - greenschist fa cies (Precambrian - Phanerozoic). The rocks of the Rupcos Group underwent diaphthoresis in the greenschist faci es in the di rect contact with the rocks of the diabase-phylliioid complex ( 13 o H H o a et al., 1969) 24 later described for the ar ea studied as Kulidzik Supergroup (Bryagovec Diabase-phyl litoid Formation) (K o )!< y x a p o s, K o )!{ y x a p o B a, 1984) . The progressive r egional metamorphism (greenschist facies) of the Bryagovec Diabase-phyllitoid For mati on overprinted retrcgrade changes into the rocks of primary amphibolite faci es . These alterations are the strongest near the direct contacts, and gradually decrease with the di stance from the latter. Such contacts have been observed along the prolongation of the Avren fault zone to the north along the valley of the Kulidzikska River (6 o H HoB et a!. , 1969) but the effects of such diaphthoresis are observed also in the area studied. This is the case of the outcrops of the Bog utevo and Vaca Formations in the northern and northwestern parts of the area (fig . 5) between the valleys of the rivers Marisnica and Kulidzikska (upper part) which before the studies of K aHa 3 H p c I< H (1967) have been referr ed to a "low-grade metamorphic Paleozoic series" (VI. B a HoB, 1961) or to a "Paleozoic diabase-phyllitoicl formation" (6 o 51 H o s et al., 1963). Mineral associations typical of the greenschist facies have been overprinted over the rocks of the Bogutevo and Vaca Formations as a result of the diapthoritic altera tions, and n amely: - quartz + chlorite + epi dote+ al bi te ± sericite; - quartz+ chlorite+ blue-green amphibole to actinolite-f- albite; - blue-green amphibole to actinolite+ albite+ chlorite± quartz; - blue-green amphibole to actinolite+chlorite+ epidote; - calcite+ epidote+ chlorite+ quartz. Relics from the minerals or rock sectors corresponding to the primary amphibo lite facies are preserved amongst the minerals of the new mineral associations. With the di s tar:~ce from the direct contact with the diabase- phyllitoid Bryagovec Formation, the intensity of the s uperimposed greenschist facies metamorphism is gradually dec reasing. It is expressed into chloritization of biotite and hornblende, sericitization, albitization , epidotization and carbonatization of the plagioclases, pelitization of the K-feldspar , and a partial recrystallization of quartz. The regional greenschist facies di aphthoresis related to the metamorphism of the Bryagovec Diabase-phyllitoid Formation of the Kulidzik Supergroup is being often confounded with the clynamometamorphic alterations into the same facies due to tec tonic movements along the big fault zones into the rocks of the Rupcos Group. This may happen when the general carbonatization of the rocks typical for the first case, and the cataclasis and m ylonitizati on typical of the second one, have not been consi dered, as well the degree of alteration in respect to the primary rocks. The dynamometamorphic alterations in the range of the Paleozoic fault zones can be hardl y eli fferentiated in the area studied by the similar alterations due to later (Alpine) movements. 4. Early A lpine dynam.ometamorphism (pre-granitic- Late Cretaceous?). The Early Alpine metamorphism is documented along the big fault zones, and the thrusting re lated to them. Its upper limit is dated with the granites which cross-cut its products, and with the Paleogene breccia-conglomerates which cover them and contain their frag ments. Dynamometamorphic alterations of this stage are observed in the Precambrian me tamorphics within the Avren and Kamilski Dol fault zones , as well as in the Pele vun thrus t sheet where they ar e widespread both in the rocks of the allochthone and the autochthone. The intensity of the dynamometamorphic greenschist faci es mineral alterations in the area full y coincides with the results of the model study by K o )!{ y x a p o B a, VI. q e B (1989) . The effects over different rock types are expressed in cataclasis, mylo nitization, formation of t ectonic breccias, kakirites etc., as well as in brittle and duc tile deformations of the minerals, granulation of quartz, intracrystalline translations, and formation of minerals typical of the greenschi st facies (chlorite, sericite, actinolite, 25 CtrniCino lithostratlgr phic units z Tepe!o-l w ' > "r=-~~=1--_ .-_-=--: _ _-==- \\ \ \ ~- \\ 111~¥T~. 1-:------_-~======\\\\ ~.":-..:..-:- ..::::: ~ \ IC J1 ~=-:::::::--=-:: 2 :6S ~---=-=-- -=- - 'l--+-+-1~~=-=-~~· · - --=-~--- 0 9--8 67 ~ ===-=~~-= ~=~ > r-_-_--:= _-_ r---- r-_ -- - -: """"!:: ~----_- 0 1:--::---_ - __ - . 1 ·a: 0 l Sl _ - ---- "' Fig. 5. Reference sections of the Rupcos Group (VII and VIII from fig. I) 26 albite, quartz de.). The myloni tization of marbles is most t ypical. They obtain a "por celain-like habit" 27 Age of the protolith of the Rupcos Group No studies aimed at the determination of the age of the Rupcos Group in the East Rhodope Mt s have been carried out up to now. The present author sampled for microphytofossil analysis graphite-rich rocks of the Cepelare and Vaca Formations but the results should be expected in the following yea rs. However , the Precambrian age of these rocks is proven by the presenc e of Vendian microphytofossils (K o zhoukharo v, 1988 ; Ko.»< yxa p o a, 1991) in the covering BryagovecDiabase-phyl- 1itoid Formation. As described hereabove, the prograde greenschi st facies metamor phism of Bryagoyec Formation was overprinted as a greenschist facies di aphthoresis over the amphibolite facies metamorphics of the Rup cos Group. The rocks of the Rupcos Group from th ei r type area in the Central Rhodope Mts contain microphytofossils which correspond to an Early Proterozoic age (T 11M o - 4> e e B , 1982 ; K o .»< y x a p o B, 1984 ; K o .»< y x a p o B, T H M o 4> e e B, I 989) . The corresponding taxa are: Protosphaeridium sp. ; Protosphaeridium tuberculiferum Tim.; Tremotosplweridium sp.; Trematosphoeridium holtedohlii Tim.; Leiosphaeridia bituminosa Tim.; Glceocapscmorpha sp.; Pterospermopsimorpha sp. The same (Ear ly Proterozoic) age is assummed also for the Rup cos Group in the East Rhodope Mts . Conclus!o11 The geologic evolution of the Precambrian metarnorphics from the East Rhodope Moun tains consists of two big stages: Precambrian and Phanerozoic. The Precambrian rocks sufferred different in type, time and intensity geologic processes . Precambrian megastage. It consists of three stages corresponding to the deposi tion time of the protoli ths of the Prarhodopi <> n , Rhodopian and Kulidzik supergroups . Our interest is focused mainly on the formation and development of the rocks of the Rho dopian Supergroup. The Rhodopian Supergroup is represented in the area studie d by the Rupcos Group which have been deposited over the Arda Group of the Prarhodopi an Supergroup after the amphibolite facies metamorphism and migmatization of the latter, and after its folding. These processes have been followed by the intrusion of the Bjala Reka grani tes (gneiss-grcmites - K o .»< y x a p o B a et a!., 1988). Th e lower boundary of the Rupcos Group is usual Jy norrRa I end subconcordant in the single outcrops but in a regional aspect ha s the features of a geographic di scordance marked by the consecutive covering of different levels of the Belopole Formation of the Arda Group by the first packet of the Cepelare Formation - the Yai ladzi k Member. The cover of the Rupcos Group known from the type area of the Rhodopian Supergroup in its normal section (K o )K y x a p o B, 1984) as Sitovo <~nd Ase novgrad Groups is missing in the East Rhodope Mts. (K o .»< y x a p o B, 1987). The rocks of the three Formations are covered in different parts of the area by the Bryagovec Di abase-phyllitoid Formation (Vendian - L. Camb rian). by the Strazec anchimetamorphic Formation (Jurassic- L. Cretaceous) or directly by different Paleogene and Neogene sediments. The rocks of the Cepelare Formation (Rhodopian Supergroup) embrace the d_ome structures formed in the Prarhodopi an Supergroup: Danai lovo dome-antic! ine, Zele zino dom-anticline, and the situated between them Konnik syncline (fig. 6, I. II , III), as well as the Tintjava syncline and the Kartalbunar brachyanticline south of the area studied. These structures characterize the Prarhodopian structural pl an. and fully cor respond in style to the dome-like and basin-like structur E's in other parts of the Rho dope Massif (K o .»< y x a p o B, 1965. 1971) . During the previous studies they have not beE'n distinguished (kl BaH o B, 196 1; Eo H HoB et al .. 1963, etc.) and hc!Ve been described toget her with the structurC's defining the Rh odopian ~ t r udu r Fig. 6. Geo logical sketch for the f2ult and fold structures 1 ~ Q uaternary and water·covered areas; 2 - Plioce ne sediments ~ nd Paleogene sedi me nts and vol cani cs; 3 - Upper Cretaceous (?) granitoicls; 4 - Rhcdcpi ;:n S upe rgroup; 5 - Prarh odopi an Supergroup; 6; - Pele\·un thrust; 7- f a ul t ~ ~nd faul t zon es (wit h number); 8 - fold structures (with number). Fa ult struct ur es: 1 - Kamilski Dol faul t, 2 - Pok rovan fault, :J- Kaleta fa ul t, 4 - Glumovs ki fa ul t, 5 - Planinec faul t, 6 - Huhl a faul t. 7 - Bruse w i fault . 8 - · Ce rni cino fault, 9 - Kohcas fa ult, 10- Bui.Ji no fault, 1/ - Ores inn fa ult zone, 12 - Rozi no fa ult , 13 - Bjala Reka fa ult zone, 14 - l\ vrrn fault zen e. Fold strurt ur l S: I - Dan11i lovo dome-anticline, I I - Zele zino dome·anti cl ine, III - Pcndalophos anticline, I V - Kami lski Dol syncline, V - Pazla k anti cline, V I - Pokrovan syndinc, V II -· Bjala Rcha do me, V III - eastern pericline of the Av ren syn· cl ine Kami Is ki Dol sync! ine, and Pendalophos ;m ticl ine (on) y with its eastern per icl ine on Bulgarian t erritory). These structures are complicat ed by smaller 2nd order anticli nes and synclines as the P azl ak anticl ine, Pokrovan syncline (f ig . 6, V and VI) etc. The detailed char acter istics of the t~ o str uctural pl ans (Prarhodopian and Rho dopian) is not the aim of the present paper . Therefor e, it should be only mentioned that they have formed in a pre-Vendi an time, most pro bably in the Late Riphean for the Rho dopian structural pl an. as far as the rocks of the Bryagovec diabase-phyllitoid Forma ti.on cover transgressively and discordantl y an al ready di sintegrated in blocks Rhodo ptan structural plan . Phanerozoic megastage. The regional greenschi st faci es metamorphism of the rocks of the Kulidzik Supergroup, and the di a phthor esis in the same faci es superimposed over the rocks of the Rup cos Group should be r elat ed to the Precambrian - Phanerozoic boundary . Since that time, a more intense influence of tectonic movement of different time and s ignificance was performed over the consolidat ed Precambrian basement which led to the contemporar y fault-block, and locally , t hrust t ectonic features . The sequence of these movements and their dynamometamorphi c influence over the rocks of the Rup- 29 cos Group have been followed in the chapter dealing with the metamorphic alterations in the Phanerozoic. The thrusts (Pelevun thrust - l1 BaH o B, 1961; 5o 5I HoB et al., 1963; I v a nov, 1965; East-Rhodope complex thrust - 5o 5I HoB, P y c e B a, 1984) are a significant element of the Phanerozoic development of the Precambrian rocks. Toge ther with the Kul idzik thrust, they are related to the big fault zones (Avren, Bjal a R eka, Oresinovo), and represent decollement structures, or epidermal structures in the sense of 5I p a HoB (1960) . Here, as well as in the other parts of the Rhodope Massif, there exist no data about large-amplitude thrusts: all such structures represent block struc tures with an "allochthone" always consisting of younger rocks, a fact di scussed in de tails by l1 BaH o B (1961) for the area studied. Reference s At an as o v, G., Go ran o v, A. 1984. On the Paleogeography of the Eastern Rhodopes. - Comptcs rendus de l'Academie bulgare des Sciences. 37, G; 783· 784. Go ran o v, A., At an as o Y, G. 19b9. Lithos trati graphic subdivision of the Ea st Rhodope and Upper T~racian Paleogene. - Gcolcgica Rhcdopico, 1; 14-21. Ivanov, R . 1965. Ober Grundgebirgsba u und seinen EinfluB a ut Petrochemic und Verleilung des J ungvulkanismus in Zmtrai massiv der Rh odcpen. - Frcib . Fsh. , c 190 ; 7-48. K o z h o u k h a r o v, D., K o z h o u k h a r ova, E., Zag or c e v, I. 1978. The Precam· brian in Bulgaria. Materials to the IGCP Project 22; 65 p. 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