Turkish Journal of Earth Sciences Turkish J Earth Sci (2013) 22: 239-246 http://journals.tubitak.gov.tr/earth/ © TÜBİTAK Research Article doi:10.3906/yer-1106-5 Revised Late Campanian-Danian age of the melange-related turbiditic sequence in the Mersin area (Central Taurides, S. Turkey) Hayati KOÇ*, Kemal TASLI, Erol ÖZER Department of Geological Engineering, Faculty of Engineering, Mersin University, 33342 Çiftlikköy, Mersin, Turkey Received: 18.06.2011 Accepted: 02.09.2012 Published Online: 27.02.2013 Printed: 27.03.2013 Abstract: A planktonic foraminiferal assemblage obtained from the Yavca stratigraphic section north of Mersin shows that the age of a melange-related turbiditic sequence extends to the Danian (Early Palaeocene). Previously, this turbiditic sequence, termed the Yavca Formation, was considered to be of Late Cretaceous or Campanian-Maastrichtian age. The formation is either depositionally overlain by the Fındıkpınarı ophiolite-related melange or tectonically by Mersin Ophiolite slices or Jurassic-Cretaceous platform carbonates. Clayey limestone and mudstone samples collected from the type area of the Yavca Formation yielded planktonic foraminiferal assemblages, which include Parasubbotina pseudobulloides (Plummer), P. varianta (Subbotina), Praemurica pseudoinconstans (Blow), P. inconstans (Subbotina), Globanomalina compressa (Plummer), G. ehrenbergi (Blow), Subbotina triloculinoides (Plummer), S. triangularis (White), Morozovella praeangulata (White), and Eoglobigerina spiralis (Bolli). These assemblages range from the late Danian P1c subzone to the basal P3a subzone. Basal red pelagic limestones are assigned here to the late Campanian-Maastrichtian, based on the presence of Radotruncana cf. R. calcarata (Cushman) and Contusotruncana cf. C. walfischensis (Todd). The age of the melange-related turbiditic sequence is revised to be late Campanian (Late Cretaceous) to Danian (Early Paleocene). This revised age provides a new insight into the evolution of the Central Taurides and helps refine palaeogeographical interpretation during this time. The timing of the ophiolite emplacement in the Central Taurides is interpreted as post-Danian to pre-Miocene (Late Palaeocene or Late Eocene). Key Words: Early Palaeocene, planktonic foraminifera, ophiolite emplacement, Central Taurides, S Turkey 1. Introduction and olistoliths (Demirtaşlı et al. 1984). Ricou (1980) gave Ophiolite-related rock assemblages overlying the Mesozoic a stratigraphic section across the Cretaceous limestone Tauride Carbonate Platform are considered to be sutured massif and ophiolitic rocks in Kavaklıpınar village and remnants of the South Neotethys Ocean and have been differentiated 3 Maastrichtian rock assemblages. From widely used in regional tectonic reconstructions (Şengör base to top these are: (1) limestones containing rudist & Yılmaz 1981; Robertson & Dixon 1984; Yılmaz 1993; fragments, Orbitoides media, and Siderolites calcitrapoides; Collins & Robertson 1997; Parlak & Robertson 2004; (2) a few metres of thick red limestones with Globotruncana Robertson et al. 2009). Late Cretaceous melange-derived arca, G. calciformis, and G. gr. stuarti; (3) 25-m-thick turbidites and associated ophiolitic melange in the Mersin greenish sandstones. He suggested that the ophiolitic area were originally studied by İlker (1975) under the nappes in the Arslanköy and Namrun (Çamlıyayla) areas name “Yavca Formation” from around Yavca village, 60 km were emplaced onto the Taurus Limestone Axis during the northeast of Mersin (Figure 1). The name Yavca Formation Maastrichtian. The Yavca Formation can be correlated with has been subsequently restricted to the melange-related the Maastrichtian “regular basal sequence” of ophiolitic turbiditic sediments (Koç et al. 1997; Taslı & Eren 1999), by melange in the Aladağ region, Eastern Taurides (Tekeli et excluding one of the associated melange units (Fındıkpınarı al. 1984). Taslı and Eren (1999) dated the red limestones in Melange of Yaman 1991; Mersin Melange of Parlak & the basal part of the Yavca Formation in the Aydıncık area Robertson 2004). Comparable sediments were termed as late Campanian, based on a planktonic foraminiferal the Arslanköy Formation, assigned a Senonian age based assemblage comprising mainly Globotruncanita on the presence of Globotruncana stuarti, Globotruncana calcarata, Gta. stuartiformis, Globotruncana arca, and tricarinata cf. fornicata, Globotruncana rosetta, Orbitoides Contusotruncana fornicata, identified from thin sections. sp., and Siderolites sp., and with a possible Danian age for Only one of numerous samples from the formation its uppermost part containing ophiolitic olistostromes yielded a few recrystallised planktonic foraminifera, which * Correspondence: [email protected] 239 KOÇ et al. / Turkish J Earth Sci Black Sea Pontdes Ankara 40°N Kırşehr Metamorphc ANKARASUTURE Massf İZMIR Beyşehr ZONE Taurde Menderes - HoyranCarbonate Aladağ Btls Metamorphc Massf suture KaramanNappers Platform Lycan Nappes MERSİN Alanya Massf MELANGE Araban Platform Mersn Hatay ANTALYA AydıncıkFg.2a COMPLEX Güzelsu Fg.3c BAER- BASSIT Troodos MELANGE Medterranean Cyprus Sea MAMONIA COMPLEX 34° N Opholtc unts 0 100 km 30°36°E Figure 1. Tectonic map of Turkey (after Parlak & Robertson, 2004), showing ophiolite-related rock assemblages and the study areas. were questionably assigned to Parasubbotina of Palaeocene lower and upper formation contacts are faulted, named age, during a recent study of the biostratigraphy and the Bozkoyak stratigraphic section with 5 washing samples palaeoenvironmental setting of the Late Cretaceous (Bo/15-19), was measured in the Aydıncık area. In total sediments of the Central Taurides (Koç & Taslı 2010). 36 samples, 21 of them washing samples while the others Additional and more detailed sampling confirmed the were thin-sectioned, were analysed. Muddy samples, occurrence of Palaeocene planktonic foraminifera within each weighing approximately 1 kg, were crushed and this formation. This study focuses on dating the melange- then soaked in dilute hydrogen peroxide (10%) for 12 to related turbiditic succession by means of its planktonic 24 h. The residues were then washed through a 100-µm foraminiferal assemblages. screen and dried out in an oven at less than 50 °C. About 250 specimens were picked and cleaned using ultrasonic 2. Materials and methods agitation for intervals of 10 to 15 s. Determination of Systematic sampling was carried out in the type area of planktonic foraminifera were then made using an optical the Yavca Formation, situated 1 km east of Yavca village stereomicroscope with 40× and 100× magnifications. (Figure 1). The type area is one of the best places to see the The free specimens of planktonic foraminifera were lower and upper depositional contacts of the formation, illustrated with field emission scanning electron which are well preserved and easily accessible. Sampling microscope (FESEM) images in the Mersin University was limited by the relative scarcity of suitable calcareous Advanced Technology, Education and Application Centre. lithologies, compared to mainly sandy and silty lithologies. Planktonic foraminiferal specimens are relatively well Another stratigraphic section further west, in which the preserved although some are recrystallised and infilled 240 KOÇ et al. / Turkish J Earth Sci with iron oxide. The specimens are stored in the Geological with Permian limestone olistoliths (Karagedik Formation), Engineering Department collection, Mersin University, Jurassic-lower Senonian carbonates (Cehennemdere Mersin. Palaeocene taxa and biozones were identified Formation), and Senonian-Danian (?) flysch containing according to the method of Olsson et al. (1999). The time ophiolitic fragments (Arslanköy Formation), which scale used in this paper is that of Gradstein & Ogg (2004). structurally overlie the ophiolitic melange. Two generalised N-S cross-sections (Figure 3) 3. Geological setting demonstrate that the Yavca Formation is sandwiched Ophiolite-related rock assemblages are widely distributed between several thrust sheets and that it structurally on the southern flank of the Bolkar Mountains, in the overlies a southward-dipping thrust sheet containing eastern part of the Central Taurides (Figures 2A and 2B). Mesozoic platform carbonate sediments or ophiolite slices Demirtaşlı et al. (1984) recognised 3 tectono-stratigraphic (Figure 3A). This lithostratigraphical unit can be traced units in the Bolkar Mountain area. The northern part of the westwards into the Aydıncık area (Figure 3B and 3C) in Bolkar Mountains consists of metamorphosed Permian- discontinuous outcrops as a result of nappe cover erosion Late Cretaceous carbonate rocks of the Bolkar Group, (Koç et al. 1997; Taslı & Eren 1999). which are either tectonically overlain by late Senonian ophiolitic melange or unconformably overlain by late 4. Lithology Maastrichtian-Tertiary volcano-sedimentary formations of The Bolkar Mountain inner platform carbonate deposition the Niğde-Ulukışla Basin. The central portion of the Bolkar is represented by the Bajocian-Santonian Cehennemdere Mountain area contains slightly metamorphosed Permian- Formation (Taslı et al. 2006). It is overlain by late Late Cretaceous carbonate-dominated rocks with diabase Campanian hemipelagic and pelagic grey limestones, intercalations that were thrust over the Late Cretaceous- which become siliceous and pinkish upwards, together Palaeocene formations of the Ereğli-Ulukışla Basin. The with centimetric to decimetric-sized slump-folds.