Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-014-1111-9

ORIGINAL PAPER

The Rhodope Zone as a primary sediment source of the southern Thrace basin (NE Greece and NW Turkey): evidence from detrital heavy minerals and implications for central-eastern Mediterranean palaeogeography

L. Caracciolo · S. Critelli · W. Cavazza · G. Meinhold · H. von Eynatten · P. Manetti

Received: 29 April 2014 / Accepted: 15 November 2014 © Springer-Verlag Berlin Heidelberg 2014

Abstract Detrital heavy mineral analysis coupled with a common origin of tectonic units exposed in NW Tur- a regional geological review provide key elements to re- key (Biga Peninsula) with those of NE Greece and SE evaluate the distribution of the Rhodope metamorphic Bulgaria (Rhodope region). The entire region displays zone (SE Europe) in the region and its role in determin- (1) common extensional signatures, consisting of com- ing the evolution of the Thrace basin. We focus on the parable granitoid intrusion ages, and a NE-SW sense of Eocene–Oligocene sedimentary successions exposed in shear (2) matching zircon age populations between the the southern Thrace basin margin to determine the dis- metapelitic and metamafic rocks of the Circum-Rhodope persal pathways of eroded crustal elements, of both Belt (NE Greece) and those of the Çamlica–Kemer com- oceanic and continental origins, as well as their differ- plex and Çetmi mélange exposed in NW Turkey. Detri- ent contributions through time. Lithological aspects and tal heavy mineral abundances from Eocene–Oligocene tectonic data coupled with geochemistry and geochronol- sandstones of the southern Thrace basin demonstrate ogy of metamorphic terranes exposed in the area point to the influence of two main sediment sources mostly of ultramafic/ophiolitic and low- to medium-grade meta- morphic lithologies, plus a third, volcanic source limited Electronic supplementary material The online version of this to the late Eocene–Oligocene. Detrital Cr-spinel chem- article (doi:10.1007/s00531-014-1111-9) contains supplementary istry is used to understand the origin of the ultramafic material, which is available to authorized users. material and to discriminate the numerous ultramafic L. Caracciolo (*) · S. Critelli sources exposed in the region. Compositional and strati- Dipartimento di Biologia, Ecologia e Scienze della Terra graphic data indicate a major influence of the metapelitic (DIBEST), Università della Calabria, via P. Bucci, cubo 4b, source in the eastern part (Gallipoli Peninsula) during the Rende (CS), Italy initial stages of sedimentation with increasing contribu- e-mail: [email protected] tions from metamafic sources through time. On the other L. Caracciolo hand, the western and more external part of the south- Chemostrat Ltd., Sandtrak Unit 1, Ravenscroft Court, ern Thrace margin (Gökçeada, Samothraki and Limnos) Buttington Enterprise Park, Welshpool, UK displays compositional signatures according to a mixed W. Cavazza provenance from the metapelitic and metamafic sources Dipartimento di Scienze Biologiche, Geologiche e Ambientali, of the Circum-Rhodope Belt (Çamlıca–Kemer complex Università di Bologna, Bologna, Italy and Çetmi mélange). Tectonic restoration and composi- tional signatures provide constraints on the Palaeogene G. Meinhold · H. von Eynatten Abteilung Sedimentologie/Umweltgeologie, palaeogeography of this sector of the central-eastern Geowissenschaftliches Zentrum der Georg-August-Universität Mediterranean region. Göttingen, Göttingen, Germany Keywords Sediment provenance · Thrace basin · P. Manetti Dipartimento di Scienze della Terra, Università degli Studi di Circum-Rhodope Belt · Biga Peninsula · Detrital heavy Firenze, Florence, Italy minerals · Cr-spinel geochemistry

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Introduction sub-depocentres of the Thrace basin (e.g. Meinhold and BouDagher-Fadel 2010; Caracciolo et al. 2011, 2012, 2013; The Thrace basin is a complex system of depocentres d’Atri et al. 2012; Maravelis et al. 2007; Maravelis and Zeli- located between the Rhodope–Strandja massifs to the lidis 2010, 2013; Cavazza et al. 2014). Three main sources north and west and the Biga Peninsula to the south. The are generally identified as the main contributors to the infill south-eastern margin of the basin is now covered by the of the Thrace basin: (1) the Rhodope–Strandja massifs Marmara Sea and deformed by the North Anatolian Fault (mostly for W and NW Thrace and the main depocentre), Zone (NAFZ). The Thrace basin is the largest and thick- (2) the Circum-Rhodope Belt (CRB; W and (?)SW Thrace) est Tertiary sedimentary basin of the eastern Balkan region and (3) the Biga (?intra-Pontide) and ˙Izmir–Ankara suture and constitutes an important hydrocarbon province (Turgut zones (S Thrace). Furthermore, an extensive volcanic source et al. 1991; Turgut and Eseller 2000; Siyako and Huvaz was also active, delivering huge quantities of volcaniclastic 2007). Most of the Thrace basin-fill deposits range from debris throughout the Thrace basin between the late Eocene the Early Eocene (Ypresian) to the Late Oligocene; maxi- and the Miocene. Detrital ophiolitic material has been docu- mum total thickness, including the Neogene-Quaternary mented almost exclusively along the southern margin of the succession, reaches 9,000 m (Yıldız et al. 1997; Turgut and basin (Limnos/Lemnos, Samothraki, Gökçeada and Gal- Eseller 2000; Siyako and Huvaz 2007). The older part of lipoli Peninsula; Fig. 1). Its origin has been recently debated the basin fills crops out extensively along the basin mar- (cf. Maravelis and Zelilidis 2013; Caracciolo et al. 2012). gins, but it is covered by Plio-Quaternary deposits in the There are different possible sources for these types of basin centre. Volumetrically, most of the Eocene–Oligocene grains: (1) the meta-ophiolitic complex of the Circum-Rho- sedimentary succession is made of basin-plain turbidites dope Belt, (2) the ophiolitic material exposed in the Biga (Aksoy 1987; Turgut et al. 1991). Sedimentation along the Peninsula of NW Turkey, (3) the peridotite bodies of the basin margins was characterised by carbonate deposits with ˙Izmir–Ankara–Erzincan (IAESZ) or intra-Pontides suture nummulitids during the Eocene and by deltaic bodies pro- zones and (4) the Lesvos “ophiolite”. Mainly based on pal- grading towards the basin centre in the Oligocene (Sümen- aeocurrents and compositional data, Maravelis and Zelilidis gen et al. 1987; Sümengen and Terlemez 1991). The west- (2010, 2013) suggested that the ophiolite source for the ern margin of the basin was characterised already in the turbidite succession exposed in the island of Limnos was Eocene by a series of coarse-grained fan-deltas prograding a southern outer arc ridge identified in the island of Les- eastward and feeding the basin-plain turbidites. The south- vos. From petrographic evidences, Caracciolo et al. (2011, ern basin margin features abundant ophiolitic and carbon- 2012) proposed that Limnos and the western Thrace basin ate olistostromes emplaced during the Eocene–Oligocene. (Evros sub-basin, NE Greece) were supplied by a common The Thrace basin was long interpreted as a forearc basin source, the CRB, delivering low-grade metamorphic mate- which developed in a context of northward subduction (Görür rial to the western sector and meta-ophiolitic detritus to the and Okay 1996). This interpretation was challenged by more southern sector (Limnos). d’Atri et al. (2012) stated that recent data emphasising the lack of both a coeval magmatic the ˙Izmir–Ankara and/or Biga (?intra-Pontide) suture zones arc and a subduction complex associated with the basin. All were the likely source for detrital Cr-spinel and ophiolite these elements—along with the correspondence between debris of the sediments exposed in the Gallipoli Peninsula subsidence pulses in the basin and lithospheric stretching in of NW Turkey. The problem is tackled in the present study the metamorphic core complexes of southern Bulgaria and through a thorough characterisation of the geology of NW the northern Aegean region—indicate instead that the Thrace Turkey coupled with information obtained from the analy- basin was likely the result of (1) post-orogenic collapse after sis of detrital heavy minerals. The chemistry of Cr-spinels the continental collision related to the closure of the Vardar of the Thrace basin constrains both the source for this type Ocean and/or (2) upper-plate extension related to slab retreat of sediments and Palaeogene palaeogeographic/geodynamic of the Pindos remnant ocean (see Cavazza et al. 2014, for a reconstructions of the SE European margin. Addressing review). An increasing number of studies, combining kine- the questions to be answered correctly is fundamental and matic framework, regional geochronological and stratigraphic only possible by considering the Thrace basin and the Biga data, refine the definition of the Thrace depocentres as a Peninsula according to geological boundaries rather than to hanging-wall supradetachment basin evolving into a strike- political borders. slip basin from the late Miocene to the present (e.g. Dinter et al. 1995; Beccaletto et al. 2007; Kilias et al. 2013). Largely on the basis of compositional data, different Geological background authors determined the main provenance signatures and sediment dispersal pathways for the western (NE Greece), The integration of surface and subsurface data shows that north-western (SE Bulgaria) and southern (NW Turkey) the sedimentary fill of the northern, western and central

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Fig. 1 a Schematic geological map of the Aegean and surrounding Thrace basin sedimentary cover of the Biga Peninsula (NW Turkey) regions showing the main geotectonic units. b Geological map show- and Rhodopian region (NE Greece, SW Bulgaria) (after Cavazza ing Palaeozoic–Mesozoic basement rocks (undifferentiated) and the et al. 2014) portions of the Thrace basin disconformably overlies the 2010). Due to the effects of extensive strike-slip tectonism, basement complexes of the Rhodope–Strandja massifs. The the southern boundary (and basement) of the Thrace basin contact between Rhodopian basement and the base of the is less well defined. Nonetheless, progressively thinner Thrace basin sedimentary fill is traceable southward in out- Eocene sedimentary rocks extend from the Gallipoli Pen- crop to the northern shores of the Gulf of Saros (Okay et al. insula into the northern part of the Biga Peninsula (Siyako

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Fig. 2 Geological maps of the study areas. a Western and southern (after Akartuna 1950). c Samothraki Island (after Heimann et al. Thrace basin (modified after d’Atri et al. 2012). The North Anatolian 1972). d Limnos Island (after Innocenti et al. 2009). The colour ver- Fault (NAF) defines the limit between samples from “South Ganos” sion of this figure is available in the web version of this article and “North Ganos” (see text for description). b Gökçeada Island et al. 1989) where—before pinching out—they overlie maximum metamorphic conditions reached prior to exhu- again metamorphic rocks attributed to the Rhodopian mation. The Kemer mica schists display medium-grade domain by Okay and Satir (2000a), Beccaletto and Jenny metamorphic conditions, whereas those exposed in Çamlıca (2004), Beccaletto et al. (2005), and Bonev and Beccaletto are typical of high-pressure/low-temperature (HP/LT) met- (2007). amorphic signatures, indicating a deeper burial of the latter In the following paragraphs, a synthetic description of with respect to the former. The mica schists contain garnet, the main tectono-stratigraphic units exposed in the Biga phengite, paragonite, albite, epidote, calcite, chlorite and Peninsula (i.e. Çamlıca-Kemer metamorphics, Çetmi titanite. Metabasites constitute a small part (<5 %) of the mélange, Ezine Group) (Fig. 2) is provided: metamorphic sequence (Aygül et al. 2012). In the metaba- Çamlıca-Kemer complex—The Cretaceous (65–70 Ma) sites, the mineral assemblage is garnet, barroisite, epidote, Çamlıca metamorphic complex is mostly composed of albite, titanite, quartz, phengite and chlorite. The lack of various types of schist intercalated with eclogitic amphi- any correspondent geological element of the Çamlıca meta- bolite bands, marble and metabasite and is in tectonic con- morphics in Anatolia suggests that its affinity must lie with tact with the mid-Cretaceous Denzigören ophiolite (Fig. 2). the large area of crystalline rocks that constitute the Rho- The Kemer mica schists are lithologically and structur- dope Massif (Okay and Satir 2000a, b). A further evidence ally comparable to the Çamlıca mica schists, cropping out of their mutual origin is represented by matching zircon south-westward (Beccaletto et al. 2007; Fig. 2). The differ- ages from metasediments of the CRB and Çamlıca–Kemer ences between the two portions of the complex stay in the complex ranging between 330 and 270 Ma (cf. Meinhold

1 3 Int J Earth Sci (Geol Rundsch) et al. 2008). In its southern part, the Çamlıca–Kemer com- by several authors with the CRB of Greece (Kopp 1969; plex is in tectonic contact with the Çetmi mélange. Kauffmann et al. 1976; Bonev and Stampfli2003 ; Okay et al. Çetmi mélange—In its northern part, the mélange is in 2010). Detrital zircons from sediments of the CRB of Greece tectonic contact with the Çamlıca mica schists, whereas in show a polymodal age distribution with a major population the southern part, it is tectonically underlain by high-grade at 370–290 Ma and minor populations at 2,100–1,780, 655– metamorphic rocks of the Kazdağ Massif (Fig. 2) through 545 and 520–450 Ma (Meinhold et al. 2010; Meinhold and the late Oligocene low-angle detachment fault that formed Kostopolous 2013). Tunç et al. (2014), although in different the Kazdağ Core Complex (Duru et al. 2004; Beccaletto proportions, have recently determined the same population et al. 2005). According to data from hydrocarbon explora- density in sediments of the CRB of NW Turkey. tion, the Çetmi mélange may also form the basement of the southern Thrace basin (Görür and Okay 1996). Main lithol- Available stratigraphic and sedimentological data for the ogies are metavolcanic (basaltic, andesitic and pyroclastics) southern Thrace basin rocks, Upper Triassic limestones, serpentinites and diverse types of sandstones. According to Beccaletto et al. (2005), A summary of the stratigraphy and sedimentology of the the Çetmi mélange has little in common with the mélanges southern Thrace basin fill can be found in Okay et al. (2010), from the ˙Izmir–Ankara and intra-Pontide sutures of north- d’Atri et al. (2012) and Cavazza et al. (2014). Innocenti et al. western Turkey, thus avoiding any direct correlation. (2009) and Maravelis and Zelilidis (2010) described the stra- The Ezine Group—It is an enigmatic geological ele- tigraphy of Limnos Island. The successions exposed in the ment in the framework of the eastern Mediterranean geol- study area range mostly from the middle Eocene (Lutetian) ogy. It is made of two unit, namely the Ezine Group s.s. and to the Oligocene (Fig. 3). Lower Eocene sedimentary rocks the Denizgören ophiolite (Fig. 2). The first consists largely are exposed at the base of the Tayfur succession (Karaağac of recrystallised Permian–Triassic carbonate rocks with a Formation). The middle–upper Eocene transition is charac- slight to pronounced (bottom-to-top of the succession) detri- terised by continental siliciclastic sediments followed by tal nature, whereas ophiolites are mostly serpentinised har- widespread nummulitic limestones (Meinhold and BouD- zburgites overlying a metamorphic amphibolite sole (Bec- agher-Fadel 2010; Caracciolo et al. 2011, 2013; d’Atri et al. caletto and Jenny 2004). The origin of the Ezine Group and 2012). On the island of Limnos, the sedimentary succession especially of the Denizgören ophiolite remains unclear. The is not older than Priabonian (Innocenti et al. 2009). From Ezine Group can be correlated to contemporary sedimentary the late Eocene (Priabonian), most of the successions record successions in Greece, deposited during the opening of the deep-marine sedimentation, including carbonate olistoliths Maliac/Meliata Ocean (Beccaletto and Jenny 2004). On the and significant volcanoclastic debris. A general coarsening other hand, the age of the Denizgören ophiolite (ca. 125 Ma, upward trend is documented for the entire southern Thrace age of the correspondent amphibolitic sole, Beccaletto 2004) basin through time (Maravelis and Zelilidis 2010; d’Atri has no time equivalent in the whole peri-Aegean region et al. 2012; Cavazza et al. 2014). Available palaeocurrent (Beccaletto and Jenny 2004). Based on the present-day geo- measurements (Limnos: Maravelis and Zelilidis 2010; south- graphic position, many authors proposed a direct correlation ern Thrace: d’Atri et al. 2012) indicate that only the most of the Denizgören ophiolite with those exposed in the island proximal facies show northward palaeocurrents whereas of Lesvos. However, the age gap between the two ophiolite most measured palaeocurrent indicators show an eastward bodies (more than 100 Ma) makes this hypothesis unlikely. palaeoflow, most likely the result of gravity flow deflection. Beccaletto and Jenny (2004) pointed out a Rhodopian affin- S140° to S120° palaeoflow deflections/reflections were doc- ity and consequent juxtaposition of the Denizgören ophiolite umented by Caracciolo et al. (2013) on the island of Lim- together with the Ezine Group onto the western end of the nos. All these elements argue for a complex basin palaeo- Sakarya zone in post-Barremian times. physiography between the Eocene and the Oligocene. The The CRB in southern Thrace—Okay et al. (2010) report on present-day configuration results from the interplay of the the existence of fragments of the CRB in the Mecidiye area Aegean regional NE-SW extension and the dismembering (northern shore of Saros Bay) where a recrystallised lime- of the southern Thrace basin caused by the NAFZ. Armijo stone, calc-schist and phyllite series are overlain by a middle et al. (1999) suggested a minimum of 85 km south-westward Eocene sedimentary succession consisting of conglomerates migration for the Biga Peninsula, so that the palaeo-southern and nummulitic limestone. The same pattern is documented Thrace margin would need to be placed at the same latitude in the western Thrace basin (Evros sub-basin, Caracciolo of the Rhodope–Thrace area (Bonev and Beccaletto 2007). et al. 2011) and in the island of Samothraki (Meinhold and Furthermore, a 25° clockwise rotation has been documented BouDagher-Fadel 2010). The southern extension of the for the island of Limnos (Kondopoulou 2000). All these ele- metamorphic basement in the Saros Bay (Gallipoli Penin- ments complicate the possible interpretation from any prov- sula) consists of slate and phyllite and has been correlated enance study in this area.

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Fig. 3 Stratigraphic sections of the southern and western Eocene–Oligocene Thrace basin fill with associated palaeoflow measurements (modi- fied after d’Atri et al. 2012; Cavazza et al. 2014)

Fingerprints of possible ophiolitic sources of the CRB exposed in the Evros region. Cr-spinel data for the Evros ophiolite suite are not available. Since differ- CRB ophiolites ent authors pointed out the mutual origin for the ophiolites exposed in the CRB (Bébien et al. 1987; Tsikouras and Dated as Early Triassic are metasedimentary rocks in struc- Hatzipanagiotou 1998; Magganas 2002; Bonev and Becca- turally lower position in the eastern CRB section, i.e. mostly letto 2007; Zachariadis 2007; Koglin et al. 2009a; Meinhold the Makri unit. Dated Early Triassic meta-ophiolites in the and Kostopolous 2013), we use as reference the detrital Cr- eastern CRB are not known. Overlying Evros ophiolites are spinel data from the Chalkidiki Peninsula and from Samo- unmetamorphosed to hydrothermally metamorphosed at thraki included in Meinhold et al. (2009) and Meinhold and the ocean floor. Certainly, the lower section of these ophi- BouDagher-Fadel (2010), respectively. Cr-number (Cr#: olites is metamorphosed to greenschist facies conditions 0.28–0.90) and Mg-number (Mg#: 0.12–0.77) contents are (e.g. Bonev et al. 2010). It is exposed on the Chalkidiki rather heterogeneous indicating a mixed (ultra)mafic source Peninsula to the west and tectonically overlies the east- of highly depleted peridotites of mainly harzburgite and ern Rhodopes, in NE Greece and SE Bulgaria to the east minor lherzolite composition (Fig. 4) of dominant supra- (Figs. 1, 2). The Samothraki mafic suite is an in situ mag- subduction zone (SSZ) origin (Fig. 5). High-grade meta- matic complex comprising gabbros, sparse dykes and basalt morphic-derived Cr-spinel grains also occur. flows and pillows cut by late dolerite dykes (Koglin 2008; Koglin et al. 2009a). SHRIMP zircon geochronology of a Lesvos ophiolites gabbro yielded 159.9 4.5 Ma (early Late Jurassic), thus ± precluding any correlation with the Lesvos ultramafic com- The Lesvos ophiolite consists of thrust sheets of man- plex further south (253.1 5.6 Ma; Latest Permian; Koglin tle peridotite overriding a tectonic mélange of metasedi- ± et al. 2009b). Different authors (Biggazzi et al. 1989; Koglin ments, metabasalts and a few metagabbros (Koglin et al. 2008) obtained similar ages (~170–150 Ma) from gabbros 2009b). Based on mineral compositions of spinel lherzolite

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Fig. 4 Cr- and Mg-numbers (Pober and Faupl 1988) for detrital Cr-spinel from the Eocene–Oligocene sediments of the Thrace basin. Top-left diagram reports compositions of Cr-spinel from potential source rocks (see text for references) and harzburgites, Koglin et al. (2009b) proposed that the exhibiting high Al and low Fe concentrations and moder- mélange and ultramafic rocks are more typical of an incipi- ate amounts of Cr and Mg. A typical signature for Lesvos ent continental rift setting rather than of a typical ophiolite Cr-spinel is given by low Cr# values (0.11–0.37). Mg# val- suite. The Lesvos Cr-spinels show a peculiar composition, ues range from 0.57 to 0.77. Cr# and Mg# values (Fig. 4)

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Fig. 5 Al2O3 vs TiO2 diagram with Cr-spinel discrimination fields ridge basalts, LIP large igneous province, SSZ supra-subduction zone. (Kamenetsky et al. 2001). Top-left diagram reports compositions of The colour version of this figure is available in the web version of Cr-spinel from potential source rocks (see text for references). ARC this article island-arc magmas, OIB ocean-island basalts, MORB mid-ocean

1 3 Int J Earth Sci (Geol Rundsch) suggest an Alpine-type peridotite origin for this ultramafic (Beccaletto et al. 2005). This model agrees with the one suite. Low TiO2 and high Al2O3 concentrations indicate a recently proposed for the equivalent CRB in NE Greece by MORB peridotite origin for minor depleted Cr-spinels in Meinhold and Kostopolous (2013). Lesvos (Fig. 5). Short review of previous provenance studies in Southern Sakarya ophiolites Thrace

The Late Cretaceous IAESZ ophiolites in north-central Previous provenance studies for the islands of Limnos Turkey are remnants of the Neo-Tethys and tectonically (Maravelis et al. 2007; Maravelis and Zelilidis 2010, override the Anatolide–Tauride platform to the south 2013; Caracciolo et al. 2011, 2012), Gökçeada (d’Atri (Sarıfakıoğlu et al. 2009). Pillow lavas, radiolarites and et al. 2012), Samothraki (Meinhold and BouDagher- pelagic limestones occur in an ophiolitic mélange in the Fadel 2010), the Gallipoli Peninsula (d’Atri et al. 2012), suture zone. Sarıfakıoğlu et al. (2009) provide Cr-spinel the Korudag-Ganos Mt. region (d’Atri et al. 2012) and data from peridotites and massive and nodular chromitites westernmost Thrace (Caracciolo et al. 2011, 2012; d’Atri from the western portion of the IAESZ (i.e. ˙Izmir-Ankara et al. 2012) report in one way or another the existence segment). Cr# and Mg# values are 0.72–0.83 and 0.42–0.68, of two or three sources (according to the single authors) respectively (Fig. 4), whereas TiO2 and Al2O3 are 0.05–0.22 for the infill of the southern Thrace basin. Keeping apart and 8.62–13.97 wt%, respectively (Fig. 5). These values the interpretation provided by single authors, it is worth indicate a SSZ-boninite origin for the IAESZ ophiolites. to note that sandstones exposed along the entire southern margin contain the same types of grains, rock and lithic Geological affinities between the Rhodope Zone and the fragments, and heavy minerals (although in variable Biga Peninsula amounts). Petrographically, they mostly show a quart- zolithic composition, with the feldspar content very lim- Possible affinities between the Rhodope Zone and the Biga ited and, in most cases, related to volcanic input. Based Peninsula can be found focusing on lithological aspects (as on textural evidences and proportions of volcanic grains well as associated stacking patterns) and comparing availa- types, Caracciolo et al. (2011, 2012) suggested a common ble protolith zircon ages. Lithologically, the CRB in Greece intermediate volcanic source for the succession exposed and the Çamlıca–Kemer metamorphic complex of the Biga on Limnos Island and in the Evros sub-basin (Alexan- Peninsula present several analogies. The latter is composed droupolis area) providing mostly vitric and felsitic neo- mainly of mica schist, calc-schist and marble with minor volcanic grains and appreciable intermediate to basic vol- metabasite and serpentinite. Lower-grade metapelitic phyl- canic rock fragments. d’Atri et al. (2012) described the lite and eclogite enclaves occur in the Çamlıca complex. A same types of volcanic textures, with the basic/interme- similar rock assemblage, but of slightly lower metamorphic diate textures (lathwork and microlithic) and neovolcanic grade, can be traced in the CRB of NE Greece (e.g. Ivanov plagioclases dominating the felsic component. Granitic/ and Kopp 1969; Papadopoulos et al. 1989; Magganas et al. gneissic lithotypes are the most representative coarse- 1991; Magganas 2002). Although in different proportions, grained felsic rock fragments. The most important detrital probability density distributions of detrital zircon U–Pb elements consist of fine-grained lithics, reflecting a domi- ages of the CRB (Meinhold et al. 2010) and the Çamlıca- nant supply from low- to medium-grade metasedimentary Kemer complex (Tunç et al. 2014) indicate mutual age pop- (slate, phyllite, mica schist) and meta-ophiolitic (diabase, ulations at 580–560 and 370–290 Ma. Meinhold and Kost- serpentinite, glaucophane schist, chert) suites of the CRB. opolous (2013) pointed out to a strong Rhodopean/Strandja Same types of lithic grains were recognised by d’Atri affinity for the (meta-)sediments of the eastern CRB. Based et al. (2012) in the successions of Gökçeada and in those on the above-mentioned evidences, we suggest here that the exposed on the Gallipoli Peninsula. Variable amounts of metasediments of the Çamlica–Kemer metamorphic com- carbonate and siliciclastic sedimentary lithics were docu- plex correspond to the Triassic–Jurassic low- to medium- mented. The petrostratigraphic evolution of the southern grade metamorphic rocks of the Makri unit in NE Greece and western Thrace basin can be summarised as follows but they experienced a higher metamorphic overprint. (for details, see Caracciolo et al. 2011; d’Atri et al. 2012; There are some striking similarities between the Cetmi Cavazza et al. 2014). mélange and the mélange-like units of the eastern Rhodope Zone in NE Greece and SE Bulgaria, like the reworking Early‑Middle Eocene of Triassic limestones, Middle Jurassic–Lower Cretaceous radiolarians, the absence of Jurassic–Cretaceous passive Sandstones from the south-western margin display a margin lithologies and a major Cenomanian transgression heterogeneous composition varying from quartzolithic

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(Qm53F19Lt28) to feldspathic litharenites (Qm21F30Lt49) Analytical results petrofacies in the Evros sub-basin and in the Gallipoli area. Most lithic fragments are from epimetamorphics of the Heavy mineral suites CRB (Caracciolo et al. 2011; d’Atri et al. 2012; Cavazza et al. 2014) and from the ophiolite terranes of the Biga Pen- Heavy mineral analyses were performed aiming at identify- insula (d’Atri et al. 2012; Cavazza et al. 2014). Increasing ing possible contrasts or variations in heavy mineral suites contributions through time from the Upper Tectonic Unit that can be accounted to sediment provenance. Results are (UTU) of the Rhodope Massif are documented (Caracciolo reported in Table 1 (as supplementary material). Heavy et al. 2011). mineral abundances consist of high proportions of zircon, tourmaline and rutile (ZTR average 48 %), with a domi- Late Eocene–Oligocene nance of zircon and subordinate amounts of tourmaline and rutile. When present, Cr-spinel and garnet average at Priabonian–Rupelian sandstones reflect a massive ca. 20 and 18 %, respectively. Subordinate quantities were delivery of high-grade metamorphic detritus from the obtained for titanite, epidote, allanite, anatase, pyroxene, Rhodope Massif in the western sector, determining a chloritoid, staurolite, kyanite, glaucophane, amphibole, quartzofeldspathic composition (Qm46F46Lt8). A vol- apatite and monazite. In general, types and association of caniclastic petrofacies (Qm8F37Lt55) developed synchro- occurring detrital heavy minerals (zircon, garnet, rutile, nously (late Eocene–early Oligocene) and is interbedded allanite, titanite, epidote, staurolite) point to a provenance with the quartzofeldspathic material. Sandstones from the dominated by low- to medium-grade metamorphic terranes, southern margin are arkosic litharenites (Qm13F48Lt39) including rocks that experienced blueschist-facies meta- including dominant neovolcanic material and intrabasinal morphism (presence of glaucophane). The massive occur- carbonate grains diluting the epimetamorphic and ophi- rence of Cr-spinel clearly points out for a key role played olitic signal. by an ultramafic, (meta)ophiolitic, source. Clinopyroxene and clinoamphibole are related to volcanic sources. Gar- net, rutile, zircon and Cr-spinel indices (GZi, RuZi, CZi Sampling and methods and CGi; Fig. 6) have been calculated according to Mor- ton and Hallsworth (1994, 1999) to further investigate the Forty-seven sandstone samples were selected for opti- information hidden in the heavy mineral assemblage. Sam- cal heavy mineral analysis, covering the entire southern ples from north of the Ganos segment of the north Anato- Thrace margin. For comparison, a set of samples from lian Fault (Fig. 2) are normally characterised by similar the Evros sub-basin (Alexandroupolis) has been included. quantities of rutile, zircon and garnet and low amounts of Heavy mineral data from the Turkish portion of the south- Cr-spinel (except in the Korudağ succession) indicating a ern margin were taken from d’Atri (2010). Heavy min- common provenance from low- and medium-grade meta- eral separates were obtained from the 63–125 µm grain- morphic terrains (Fig. 6, GZi vs RuZi). Samples from south size fraction through standard separation technique using of the Ganos fault show a higher variability. In fact, Ypre- sodium polytungstate (ρ 2.89 g/cm3). Detrital Cr-spi- sian to Bartonian (lower–middle Eocene) samples from the = nels from 11 selected samples were embedded in epoxy Karaağac and Fıçıtepe formations display high contents in resin and polished for microprobe analysis. In total, 325 zircon with negligible amounts of garnet, rutile and Cr-spi- grains were chosen from the bottom and top of four dif- nel. Middle Eocene to Oligocene sediments from S¸arköy, ferent formations (four samples from Limnos Island, two Tayfur, Gökçeada and Limnos record increasing values of from S¸arköy, three from Tayfur, two from Gökçeada). RuZi, GZi, CZi and CGi indexes, indicating the progressive Data from the CRB of the Chalkidiki Peninsula (4 sam- influence of a new source in the basin. ples, 202 grains) are from Meinhold et al. (2009). Data The best way to investigate the information hidden in the from Samothraki (3 samples, 202 grains) are from Mein- heavy mineral assemblage is to treat them as a composi- hold and BouDagher-Fadel (2010). Chemical data were tion. In order to avoid the non-negativity and constant-sum obtained using a JEOL electron microprobe (JXA-8900 constraints on compositional variables, we performed the RL) equipped with five wavelength dispersive spectrom- centred log-ratio transformation as introduced by Aitchison eters operating at the Geoscience Centre Göttingen. Oper- (1982, 1986, 1997). We applied principal component anal- ating conditions were 20 kV accelerating voltage with ysis (PCA) for a set of orthogonal linear combinations of a beam current of 20 nA and a beam diameter of 3 µm the variables (or in geometric terms, a rotation of the axes to determine Mg, Al, Cr, Fe, V, Si, Ti, Mn, Ni and Zn of the sample space), such that the new variables (or the concentrations. projections of the data set onto the new axes) are mutually

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angle between the variables, with 0° meaning dependence, 90° independence, 180° inverse proportionally) between heavy mineral species in the biplot (Fig. 7). A more care- ful analysis allows recognising a group of variables repre- sented by allanite other epidotes titanite. This group + + is placed opposite to Cr-spinel, pointing to an inverse dependence for this group of variables. Zircon, tourmaline, rutile and garnet do not show appreciable correlating ele- ments and place in between. Further information can be obtained by plotting sub-compositions, obtained by plot- ting two “depending” variables and a third independent one in a ternary plot. Results are reported in Fig. 9. All of the four selected ternary plots indicate a clear compositional difference between successions exposed to the north of the Ganos fault with those to the south. This difference is determined by the Zr–Rt–Grt association for the N Ganos and by the Cr-Sp–Grt–Rt–Ep association for the south- ern Ganos depozones. Samples from north of the Ganos fault, in particular those from the Korudağ and Kes¸an stratigraphic sections, reflect a mixed provenance from ultramafic, low- and medium-grade metamorphic sources, whereas those from Alexandroupolis do not show compo- sitional signatures indicating inputs from ultramafic rocks. Samples from south of the Ganos fault are characterised by dominant ultramafic inputs with important contributions from medium-grade metamorphic rocks and subordinate low-grade metamorphic sources.

Detrital Cr‑spinel chemistry

The most effective way to obtain meaningful host-rock indi- cations from Cr-spinel chemistry is to measure elements that present a high variability, as Cr# (Cr/Cr Al), Mg# 2 3 3 + 3 (Mg/Mg Fe +), TiO and Fe +# (Fe +/Cr Al Fe +) Fig. 6 Provenance sensitive heavy mineral indices determined on + 2 + + the 63–125 µm fraction of sandstone samples (calculated according (e.g. Dick and Bullen 1984; Pober and Faupl 1988; Barnes to Morton and Hallsworth 1994, 1999). GZi % garnet in total/gar- and Roeder 2001; Kamenetsky et al. 2001). These vari- net plus zircon, RZi % rutile in total/rutile= plus zircon, CZi % = = ables have proven useful to discriminate detrital Cr-spinel chrome spinel in total/chrome spinel plus zircon, CGi % chrome too (e.g. Pober and Faupl 1988; Lenaz et al. 2000; Lužar- spinel in total/garnet plus chrome spinel. Numbers beside= symbols indicate the stratigraphic position within the corresponding succes- Oberiter et al. 2009) and Cr# is generally used as an indica- sion of analysed samples to facilitate the recognition of heavy min- tor of the degree of partial melting since it is strongly par- eral trends. The colour version of this figure is available in the web titioned into the solid phase. Mg# is generally controlled version of this article by the Cr and Al activity in spinels and generally decreases with increasing Cr# (Dick and Bullen 1984). Detrital Cr- uncorrelated. These new variables are called principal com- spinels from the southern margin of the Thrace basin dis- ponents (PC), and by construction they are obtained in play a wide range of Cr# and #Mg values. Most of the ana- decreasing order of variance. This makes the first few PC to lysed grains fall in the fields accounted by Pober and Faupl be representative of the structural variability of the data set, (1988) for lherzolites and harzburgites (Fig. 4). Although leaving for the remaining PC just the random noise. One showing a wide distribution, Cr-spinel compositional of the more effective ways to graphically illustrate com- trends are very similar in each of the selected stratigraphic position and principal components is the biplot. A more successions with no appreciable differences according to detailed guide about how to interpret biplots can be found stratigraphic age. Cr# and Mg# values are 0.16–0.93 and in Aitchison (1997) and Caracciolo et al. (2012). At first 0.1–0.8, respectively, suggesting a mixed ultramafic source glance, there are no clear correlations (expressed by the from lherzolites to harzburgites. Furthermore, a few spinel

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Fig. 7 Biplot diagram showing the relationships among most representative detrital heavy minerals. Ep epidote, Grt garnet, All allanite, Tt titanite, Tur tourmaline, Rt rutile, Zr zircon, Cr-Sp chrome spinel, Pc principal component. The colour version of this figure is available in the web version of this article

3 grains have very low values of Fe +# (0.10–0.79) pointing monazite and pyroxenes rarely occur. The garnet/epidote/ to a metamorphic origin as being derived from high-grade titanite/rutile/allanite association is well documented in the metamorphic rocks (Barnes and Roeder 2001). Samples garnet-mica schists and metabasites exposed in the Kemer from the island of Limnos (Fig. 4) display the highest Cr# metamorphic complex (Aygül et al. 2012). Abundant Cr- variability (0.16–0.85), with <5 % of them plotting below spinel is attributed to the presence of numerous ophiolitic/ 0.35, the lower lherzolite field and Mg# ranging between ultramafic rocks surrounding the southern margin of the 0.36 and 0.80. Most of the analysed grains show composi- Thrace basin. Coupling the information from heavy miner- tions of Cr-spinel from harzburgites and lherzolites. Apart als (d’Atri 2010; d’Atri et al. 2012; this study) with those from the low Cr# tail, the same pattern can be described from sandstone framework petrology (Caracciolo et al. for the successions of Samothraki, Gökçeada and S¸arköy. 2011; d’Atri et al. 2012; Cavazza et al. 2014), high con- Appreciable amounts of detrital Cr-spinels from Samoth- centrations of zircon are attributed to widespread low-grade raki match the metamorphic spinel composition (Meinhold metamorphic rocks (phyllite and fine-grained schists) likely and BouDagher-Fadel 2010). The Tayfur succession resem- those from the Makri unit of the CRB and the Çamlıca bles the same pattern described for the island of Limnos. complex. Compositional signatures point out for complex According to Kamenetsky et al. (2001), residual spinels dispersal pathways delivering, in different proportions at are mostly located in the middle of the field for the supra- different times, material from all of the accounted sources subduction zone peridotites. In minor amounts, magmatic of sediment. spinels are recognised between the MORB and arc basalt regions, whereas a negligible number of crystals fall within Early‑middle Eocene (Ypresian‑Lutetian) the MORB peridotite field (Fig. 5). The latter, having Cr# < 0.35, represent only 3.95 % of the analysed grains Ypresian sediments from the Karağac Formation display and display low TiO2 and high Al2O3, falling within the very high zircon contents at the base, evolving upsec- lherzolite field. tion to rutile garnet (RuZi/GZi, Fig. 6) and Cr-spi- + nel Garnet (CZi/CGi, Figs. 6, 8) rich compositions. In + terms of contributions, this suggests that the first input Discussion of sediments in southern Thrace has to be assigned to the low-grade metamorphic rocks of the CRB/Çamlica- Provenance deduced from heavy mineral analysis Kemer complex, with increasing ophiolitic and medium- grade metamorphic material being delivered through time. In the studied samples, the following heavy minerals The continental/deltaic nature of sediments and north- were recognised (in order of decreasing abundance): zir- directed palaeoflows (Fig. 3) allow placing the eroded con > Cr-spinel > garnet > rutile > epidote > titanite > tour- terranes immediately to the south of the Tayfur depo- maline > allanite and common metamorphic-related min- centre (Fig. 9). Lutetian sediments south of the Ganos erals as staurolite, kyanite and glaucophane. Amphibole, fault (Gökçeada, Fiçitepe) were mostly derived from the

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Fig. 8 Ternary plots representing sub-compositions deduced from set ternary plots represent most representative heavy mineral trends the biplot figure. Ep epidote, Grt garnet, Rt rutile, Zr zircon, Cr-Sp within sampled successions. The colour version of this figure is avail- chrome spinel. Grey areas represent zones of mixed provenance. Off- able in the web version of this article erosion of ophiolitic terranes with increasing inputs from ultramafic and medium-grade metamorphic lithologies low- to medium-grade metamorphic sources through through time. Samples from Tayfur and Gökçeada docu- time. According to palaeoflows measurements (Fig. 3), ment an increasing contribution from metapelitic rocks of ophiolitic terranes feeding the Lutetian basin need to be the CRB/Kemer–Çamlica complex. Such higher concen- placed at the western margin of the basin (Fig. 9a). North trations of zircon in samples from Tayfur point to a pos- of the Ganos fault (Alexandroupolis and Ganos), the sedi- sible sediment recycling beside a supply from low-grade mentation was mostly controlled by the erosion of the metapelitic rocks supplied from the south (Figs. 3, 9). low-grade metamorphic rocks of the CRB in the western Apart from the higher amounts of zircon detected in the sector (Alexandroupolis), and by that of ultramafic rocks Tayfur succession, the same pattern can be described for in the eastern part (Ganos). the upper part of the succession exposed in Gökçeada. The increasing contribution from low-grade metapelitic rocks Late Eocene–Oligocene (Priabonian‑Chattian) is in this case highlighted by the increase in the zircon– garnet association (Figs. 7, 9). Both heavy minerals evo- The relative abundance of heavy minerals from Priabonian lutionary patterns and palaeoflows directions support the and Oligocene sediments suggests a major role exerted by hypothesis of a similar evolution for these two depocen- the metapelitic sources throughout the southern Thrace tres. Priabonian sediments from the island of Limnos were basin. Samples from S¸arköy display a mixed composi- mostly derived from a mix of dominant ultramafic source tion determined from the erosion of both metapelitic and and zircon–garnet-rich metamorphic rocks. Increasing ultramafic lithologies, likely the Kemer complex and the rutile and garnet contents in Oligocene sediments suggest Çetmi mélange. However, the relative enrichment of gar- a progressive influence of medium-to high-grade metamor- net and Cr-spinel with respect to rutile and zircon indi- phic terranes placed to the SE and E (according to a mini- cates an evolution from a mixed delivery of ultramafic mum of 25° rotational restoration). Samples from the north and low-grade metamorphic rocks to the erosion of mixed of the Ganos fault display mixed compositional signatures

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Fig. 9 Palaeogeographic reconstruction for the Eocene–Oligocene showing basement highs to the north and south supplying detritus to the southern Thrace basin. The colour version of this figure is available in the web version of this article

according to a provenance from low- to medium-grade Provenance deduced from Cr‑spinel chemistry metamorphic and ultramafic sources. Sediments from the Ganos Mountains and Korudağ reflect increasing contents Cr-spinel is considered to have a considerable chemical and in garnet and zircon and a corresponding decrease in Cr- mechanical stability (e.g. Morton and Hallsworth 1994, spinel, pointing to a dominant role exerted by metamor- 1999). Consequently, we assume that possible modifications phic terranes between the late Eocene and Oligocene. of its chemistry induced by chemical weathering are negli- Coeval samples from the Alexandroupolis basin display gible. On the other hand, its survivability potential to low-T a garnet–rutile increase and a general zircon decrease metamorphism is extremely high due to its pristine forming according to a major contribution from Rhodopian terranes conditions. Thus, any possible temperature-induced further from the late Eocene. modifications (diagenesis, low-temperature metamorphism)

1 3 Int J Earth Sci (Geol Rundsch) can be excluded, and the composition of detrital Cr-spinel • NE–SW- and NNE–SSW-directed Early Eocene syn- can be taken as representative of its source. Careful analysis orogenic extension is recorded in both the eastern Rho- of the Cr# vs Mg# and Al2O3 vs TiO2 plots provides useful dopes and Biga Peninsula (Krohe and Mposkos 2002; insights on the provenance of Cr-spinels. If we compare Cr- Bonev and Beccaletto 2007). The Miocene post-oro- spinel compositions from possible source rocks, it is clear genic extension is found in the Kazdağ Massif (Duru that there is a remarkable difference between Lesvos and et al. 2004; Cavazza et al. 2009). the remaining available data (Figs. 4, 5). Peridotites from • Comparable crustal thickness (ca. 30 km) and uniform Sakaryan ophiolites display a different composition, with a lithospheric vertical distribution between the Rhodope group of Cr-spinels from chromitites plotting slightly outside Zone and the Biga Peninsula (Papazachos and Scordi- of the harzburgites field. Conversely, Sakaryan harzburgites lis 1998; Saunders et al. 1998; Bonev and Beccaletto and the CRB peridotites group plot in the harzburgites field 2007). and show a wide distribution. The low Cr# values (coupled • According to palinspastic restoration from literature with the minor depletion) of Cr-spinels from Lesvos allow (Armijo et al. 1999), the Biga Peninsula needs to be excluding the latter among the possible sources for the ophi- shifted at least 85 km to the north-east. Between the olitic material occurring in the southern Thrace sediments. A Eocene and the Oligocene, the southern Thrace basin minor exception could be represented by Cr-spinels from the was structured as a graben (Karfakis and Doutsos 1995; island of Limnos displaying Cr# < 0.35 in <3 % of the ana- Bonev and Beccaletto 2007) with its northern margin lysed grains. Excluding Lesvos as the source candidate, it is constituted by the Rhodope s.s. and the CRB (deliver- highly probable that the southern portion of the Thrace basin ing material into the northern Evros sub-basin) and the received its (ultra)mafic detritus from Vardarian ophiolites southern margin made up of CRB equivalent units (e.g. with similarities to the Chalkidiki, Evros and Samothraki the Çamlica-Kemer complex) and Çetmi mélange. The ophiolite complexes, as these complexes comprise various eastward palaeoflows preserved in most of deep-water types of mafic and/or ultramafic rocks of mid-ocean ridge, sediments suggest the presence of metapelitic palaeo- island-arc and supra-subduction zone affinities (Tsikouras highs in the SW and central part of the basin (Fig. 9). et al. 1990; Tsikouras 1992; Tsikouras and Hatzipanagiotou 1998; Magganas 2002; Pe-Piper and Piper 2002; Zachariadis 2007; Bonev and Stampfli 2009; Koglin 2008; Koglin et al. Conclusions 2009a; Meinhold and BouDagher-Fadel 2010). Possible con- tributions from the Sakarya Zone cannot be excluded from The review of geological data indicates that the pre-Eocene detrital Cr-spinel chemistry. A review of available geody- basement exposed on the Biga Peninsula needs to be con- namic and geological data can shed light on the problem. sidered as part of the Rhodope metamorphic zone. North of the Kazdağ Massif, the Çetmi mélange and the Çamlıca- Geodynamic affinities between the Rhodope Zone and the Kemer metamorphic complex exhibit the same rock asso- Biga Peninsula ciation documented by several authors in the Circum-Rho- dope Belt (CRB) of NE Greece and SE Bulgaria. The entire There are several geodynamic features indicating a mutual Rhodope/Biga Peninsula zone displays (1) similar granitoid tectono-sedimentary evolution of the Thrace basin margins, intrusion ages, in particular those related to the closure likely the Rhodope s.l. and metamorphic rocks exposed on of the Vardar Ocean (at ca. 53 Ma) and those at the Oli- the Biga Peninsula. All possible considerations necessarily gocene–Miocene transition (32–21 Ma), (2) similar direc- need to take into account the position of the Vardar subduc- tion of kinematic indicators pointing to a common NE-SW tion zone, locally located underneath the Rhodope during synorogenic extension, (3) matching zircon populations the Maastrichtian–Palaeocene and the southward shift of between the CRB and the Çamlıca–Kemer metamorphic the subduction zone already during the Eocene (e.g. Bonev complex. and Beccaletto 2007; Caracciolo et al. 2012; Jolivet et al. 2013). Key geodynamic signatures are as follows: • The stratigraphic architecture of the southern Thrace basin presents several analogies along its margin, • Granitoid intrusions that followed the closure of the with most lower–middle Eocene sediments being Vardar Ocean occurred synchronous in the eastern Rho- continental/siliciclastic and passing up-section, during dopes and the Biga Peninsula at ca. 53 Ma (Bonev and the Bartonian, into nummulitic limestone (Fig. 3). From Beccaletto 2007; Beccaletto et al. 2007). A second gen- the upper Eocene to Oligocene, the southern margin eration of granitoid intrusions is recorded in both the underwent complex geological conditions determined eastern Rhodopes and Biga Peninsula between 32 and by the interplay of rapid subsidence and magmatism 21 Ma (Del Moro et al. 1988). giving place to an extensive deep-water sedimentation.

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• Heavy mineral assemblages indicate that the oldest References exposed Ypresian sandstones from the Tayfur sub-depo- centre were mostly derived from the erosion of the Çam- Aitchison J (1982) The statistical analysis of compositional data (with lica complex. Lutetian and Priabonian sandstones record discussion). J R Stat Soc Ser B 44:139–177 Aitchison J (1986) The statistics analysis of compositional data. the progressive uplift and erosion of ultramafic terranes Chapman & Hall, London 416 pp of the Biga Peninsula and increasing contributions from Aitchison J (1997) The one-hour course in compositional data anal- the metapelitic sources of the Kemer-Çamlica complex. ysis or compositional data analysis is simple. In: Pawlowsky- Priabonian–Rupelian sandstones document the influ- Glahn V (ed) Proceedings of IAMG’97: the third annual confer- ence of the International Association for Mathematical Geology, ence of a volcanic source, delivering material throughout International Center for Numerical Methods in Engineering the whole southern Thrace basin. Oligocene sandstones (CIMNE), Barcelona (E), pp 3–35 reflect dominant contributions from garnet-rich mica Akartuna M (1950) Imroz Adasında Bazı Jeolojik Müs ahadeler. Tür- schists and decreasing amounts of material from ultra- kiye Jeoloji Kurumu Bulteni 2(2):8–18 (in Turkish) Aksoy Z (1987) Depositional environment of the sequences in the mafic sources. The successions north of the Ganos fault Barbaros–Kesan–Kadiköy–Gaziköy region (southern Thrace). In: display a higher degree of mixing between metapelitic Proceedings of the 7th petroleum congress of Turkey, Ankara, pp and ultramafic rocks of the CRB/Kemer–Çamlica and 292–311 (in Turkish) increasing influence from Rhodopian terranes. Armijo R, Meyer B, Hubert A, Barka A (1999) Westward propagation of the north Anatolian fault into the northern Aegean: timing and • Detrital Cr-spinel compositions display very homog- kinematics. Geology 27:267–270 enous distributions in all of the analysed successions Aygül M, Gültekin T, Okay AI, Satir M, Meyer HP (2012) The Kemer reflecting a provenance from a mixed (ultra)mafic Metamorphic Complex (NW Turkey): a subducted continental source of highly depleted peridotites, mostly harzbur- margin of the Sakarya zone. Turk J Earth Sci 21:19–35 Barnes SJ, Roeder PL (2001) The range of spinel composition in ter- gites and subordinate lherzolites. restrial mafic and ultramafic rocks. J Petrol 42:2279–2302 Bébien J, Baroz F, Caperdi S, Venturelli G (1987) Magmatismes The possible inclusion of Lesvos among the possible basiques assosiés à l’ouverture d’un basin marginal dans les sources of ultramafic material is rejected according to a Hellénides internes au Jurassique. Ofioliti 12:53–70 Beccaletto L, Jenny C (2004) Geology and correlation of the Ezine Zone: clear difference in Cr# and Mg# numbers. Contributions a Rhodope fragment in NW Turkey? Turk J Earth Sci 13:145–176 from the Sakarya/intra-Pontide–IASZ are here disregarded Beccaletto L, Bartolini A-C, Martini R, Hochuli PA, Kozur H (2005) for a number of reasons. Cr-spinel compositions from the Biostratigraphic data from the Çetmi melange, northwest Turkey: Sakaryan terranes south of the Biga Peninsula cluster in palaeogeographic and tectonic implications. Palaeogeogr Pale- oclimatol Palaeoecol 221:215–244 narrow areas, especially those from chromitites. Looking at Beccaletto L, Bonev N, Bosch D, Bruguier O (2007) Record of a Al2O3 and TiO2, Sakaryan Cr-spinels cluster in the fields Paleogene syn-collisional extension in the north Aegean region: evidence from the Kemer micaschists (NW Turkey). Geol Mag for island-arc (ARC) and low-Al2O3 supra-subduction zone (SSZ) peridotites that cannot be directly excluded as pos- 144:393–400 Biggazzi GA, Del Moro F, Innocenti F, Kyriakopoulos P, Manetti P, sible sources. Being the Çamlica-Kemer complex and the Papadopoulos P, Norilliri A, Magganas M (1989) The magmatic Çetmi mélange already exposed at the time of deposition, intrusive complex of Petrota, West Thrace: age and geodynamic and considered the depositional styles of analysed succes- significance. Geol Rhodopica 1:290–297 sions, the presence of fluvial routing systems delivering Bonev N, Beccaletto L (2007) From syn- to post-orogenic Tertiary extension in the north Aegean region: constraints on the kin- material from the Sakaryan terranes (Karakaya Complex) ematics in the eastern Rhodope–Thrace, Bulgaria–Greece and seems unlikely. On the other hand, the distribution pattern the Biga Peninsula, NW Turkey. In: Taymaz T, Yilmaz Y, Dilek and the depleted character of analysed Cr-spinel grains Y (eds) The geodynamic of the Aegean and Anatolia. Geological indicate supplies from (ultra)mafic detritus from Vardar- Society, London, Special Publications, 291, pp 113–142 Bonev NG, Stampfli GM (2003) New structural and petrologic data ian ophiolites, namely the Chalkidiki, Evros and Samoth- on Mesozoic schists in the Rhodope (Bulgaria): geodynamic raki ophiolite complexes, as they comprise various types of implications. Comptes Rendus Geosci 335:691–699 mafic and/or ultramafic rocks of mid-ocean ridge, island- Bonev N, Stampfli G (2009) Gabbro, plagiogranite and associ- arc and supra-subduction zone affinities. ated dykes in the supra- subduction zone Evros Ophiolites, NE Greece. Geol Mag 146:72–91 Bonev N, Spikings R, Mortiz R, Marchev P (2010) The effect of early Acknowledgments Dr. F. Muto and Dr. R. Dominici from the Uni- Alpine thrusting in late-stage extensional tectonics: evidence versity of Calabria and Dr. N. Kolios are gratefully acknowledged for from the Kulidzhik nappe and the Pelevun extensional allochthon their help in the field. This research has been carried out within the in the Rhodope Massif, Bulgaria. Tectonophysics 488:256–281 MIUR-ex60% Projects (Relationships between Tectonic Accretion, Caracciolo L, Critelli S, Innocenti F, Kolios N, Manetti P (2011) Volcanism and Clastic Sedimentation within the Circum-Mediterra- Unraveling provenance from Eocene-Miocene sandstones of the nean Orogenic Belts, 2006–2013; Resp. S. Critelli), the 2009 MIUR- Thrace Basin, NE Greece. Sedimentology 58:1988–2011 PRIN Project 2009PBA7FL_001 “The Thrace sedimentary basin Caracciolo L, von Eynatten H, Tolosana-Delgado R, Critelli S, Man- (Eocene-Quaternary) in Greece and Bulgaria: stratigraphic deposi- etti P, Marchev P (2012) Petrological, geochemical, and statistical tional architecture and sediment dispersal pathway within post-oro- analysis of Eocene-Oligocene sandstones of the western Thrace genic basins.” (Resp. S. Critelli). Basin, Greece and Bulgaria. J Sediment Res 82:482–498

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