Turkish Journal of Earth Sciences (Turkish J. Earth Sci.), J.K.Vol. NIELSEN 21, 2012, pp.ET AL.391–405. Copyright ©TÜBİTAK doi:10.3906/yer-1011-40 First published online 28 May 2011 Ichnology of the Miocene Güneyce Formation (Southwest Turkey): Oxygenation and Sedimentation Dynamics JAN KRESTEN NIELSEN1, MUHİTTİN GÖRMÜŞ2, KUBİLAY UYSAL2 & SÜVEYLA KANBUR2 1 Statoil ASA, Development and Production Norway, Field Development, P.O. Box 273, NO-7501 Stjørdal, Norway (E-mail: [email protected]) 2 Süleyman Demirel University, Department of Geological Engineering, TR−32260 Isparta, Turkey Received 07 December 2010; revised typescripts received 18 March 2011 & 22 May 2011; accepted 28 May 2011 Abstract: Th e Güneyce Formation is well exposed in the Lake District of southwestern Turkey. It was deposited in the early Miocene in the Neotethys ocean and contains a large variety of trace fossils. Th e following ichnotaxa were recognized: Chondrites intricatus, C. targionii, ?Cosmorhaphe isp., Helminthopsis isp., Helminthorhaphe fl exuosa, Lorenzinia isp., Naviculichnium marginatum, ?Nereites isp., Ophiomorpha rudis, ?Phycosiphon incertum, Planolites beverleyensis, cf. Rhizocorallium isp. and Th alassinoides suevicus. Th ere is a lateral trend from proximal turbiditic successions to distal low-oxygen shaly mudstone. Ophiomorpha rudis ichnosubfacies, Paleodictyon ichnosubfacies of the Nereites ichnofacies and Zoophycos ichnofacies were identifi ed. Key Words: trace fossils, turbidites, ichnofacies, oxygenation, Neotethys Miyosen Yaşlı Güneyce Formasyonu (GB Türkiye) İz Fosilleri: Oksijenleşme ve Sedimantasyon Dinamiği Özet: Güneyce Formasyonu çökel dizilimleri güneybatı Türkiye’de Göller Yöresinde önemli yüzeylenmeler vermektedir. Çökelim, Neotetis Okyanusu’nda erken Miyosen zamanında gerçekleşmiştir. Formasyon içerisinde belirlenen iz fosiller şunlardır: Chondrites intricatus, C. targionii, ?Cosmorhaphe isp., Helminthopsis isp., Helminthorhaphe fl exuosa, Lorenzinia isp., Naviculichnium marginatum, ?Nereites isp., Ophiomorpha rudis, ?Phycosiphon incertum, Planolites beverleyensis, cf. Rhizocorallium isp. ve Th alassinoides suevicus. İstift e, yakınsak turbiditik istifl erden düşük oksijenli şeylli çamurtaşına yanal geçişler bulunmaktadır. Ayrıca, formasyonda Ophiomorpha rudis, Paleodictyon ve Zoophycos iknoaltfasiyesleri tanımlanmıştır. Anahtar Sözcükler: İz fosiller, türbidit, iknofasiyes, oksijenleşme, Neotetis Introduction (Burdur) (Figure 1). Th e Triassic to Early Cretaceous Isparta Çay Formation, comprising radiolarite chert Th e geology of the Isparta Angle in southwestern and platy and turbiditic limestones, is erosively and Turkey is structurally complex. Various allochthonous unconformably overlain by Miocene formations: (Antalya and Lycian nappes) and autochthonous units have been recognized (e.g., Poisson 1967; the Karabayır, Güneyce and Gökdere formations, Gutnic et al. 1979; Poisson et al. 1983; Yalçınkaya which were formed in a regionally large basin. Th e et al. 1986, Yalçınkaya 1989; Şenel 1997). Th ey siliciclastic successions of the Güneyce Formation comprise Mesozoic and Palaeogene successions of are characterized by abundant trace fossils. In the Neotethys, which are commonly unconformably addition to the microfossil content, they can provide overlain by younger deposits (see Nielsen et al. 2010 complementary data about the palaeoenvironment. and references therein). Th is is also recognized in the For this reason, the Güneyce Formation is of areas of Dereboğazı (Isparta), Ağlasun and Sagalassos particular interest because it extends laterally for 391 ICHNOLOGY OF THE MIOCENE GÜNEYCE FORMATION, SW TURKEY Bulgaria Black Sea Georgia İstanbul Ankara Turkey Isparta Aegean Sea Aegean Antalya Adana Cyprus Syria Mediterranean Sea ei Qa Isparta SAVKÖY Mzd plQ g 1 plQ ei LAKE g plQ GÖLCÜK g AK SU Mza1 F Mza2 AU LT mig plQ g mi go Mt. AKDAĞ Mzl2 2 mi 4 k Sagalassos Mza2 Mz Mz l2 l2 mi 3 k Ağlasun Mzd Mzl1 Qa Q a migo plQc Quaternary city mi g Miocene mik plQg eoli Pliocene-Quaternary village ei Eocene-Oligocene palk Palaeocene Mzl2 Lycian Nappes 1 sample locality. Mza2 Mz l1 Antalya Nappes Mza1 N thrust Mz d Davraz Limestone 5 km normal fault Figure 1. Geological map of the study area within the Isparta Angle, Turkey. Localities of the Miocene Güneyce Formation are indicated by numbers (1 –4). Modifi ed from Gutnic et al. (1979), Şenel (1997) and Nielsen et al. (2010). 392 J.K. NIELSEN ET AL. many kilometres. Th e aim of this study is to provide (Akbulut 1980; Yalçın 1993; Görmüş & Hançer 1997). the fi rst overview of trace fossils from the Güneyce Among these, we only report the stratigraphical Formation. Th e presence of trace fossils is discussed in and ichnological data from the siliciclastic rocks of terms of palaeoenvironmental conditions in relation the Güneyce Formation (Figures 1 & 2). Previous to sedimentation dynamics, substrate consistency, records gave details of the other Miocene formations oxygenation and other parameters. (Yalçınkaya et al. 1986; Yalçınkaya 1989; Yalçın 1993; Yağmurlu 1994; Görmüş & Hançer 1997; Şenel 1997; Geological Setting Görmüş et al. 2001; Poisson et al. 2003). In the study area, Miocene formations include Th e name of the Güneyce Formation is derived the Karabayır, Güneyce and Gökdere formations from Güneyce village, southwest of Isparta AGE LITHOLOGY a alluvium Q c clastics QUATERNARY plQ CENOZOIC a2 g Gölcük volcanics Mz plQ s e TERTIARY PLIOCENE pp a l2 Lycian Nappes TRIASSIC talya N Mz n A a1 l1 Mz MESOZOIC Mz go Gökdere F ormation mi MESOZOIC g Güneyce Formation 1-4 mi k KarabayıF r ormation MIOCENE mi CRETACEOUS Davras Limestone i İncesu Formation b eol Mz TERTIARY Isparta Formation CENOZOIC EOCENE- OLIGOCENE i e JURASSIC Koçtepe Formation k EOCENE TRIASSIC pal PALAEOCENE Figure 2. Stratigraphical overview of Mesozoic and Cenozoic formations exposed in the Burdur and Isparta regions. Structural nappes are indicated by older units on top of younger ones. Stratigraphical levels of localities are indicated by rectangular symbols. From Nielsen et al. (2010). 393 ICHNOLOGY OF THE MIOCENE GÜNEYCE FORMATION, SW TURKEY (Akbulut 1980). Rhythmical siliciclastic sediments bijugatus. Reworked Cretaceous nannofossils: Micula were identifi ed as ‘the Burdigalian fl ysch’ by decussate, from the Cretaceous/Palaeogene boundary: Gutnic et al. (1979). Th e Ağlasun Formation is a Aspidolithus parcus constrictus, Briantolithus sparsus, more recent synonym of the Güneyce Formation Litraphidites quadratus, Microrhabdulus attenuatus, (Yalçınkaya 1989; Karaman 1990). We prefer the Micula decussata, Prinsius bisulcus, Stradneria original formation name given by Akbulut (1980) crenulata, Th oracosphaera saxea and Watznaveria according to stratigraphical rules (Hedberg 1976). barnesae. Th e fossils of the entire Güneyce Formation Th e Güneyce Formation is exposed widely around indicate an early Miocene age, i.e., Aquitanian− İmrezi, Kışla, Darıören and Güneyce villages. Burdigalian−?Langhian age (Görmüş et al. 2001, Siliciclastic sediments are dominant and include 2004). Lithological characteristics and fossil contents various sedimentary facies such as (1) mudstone- of the Güneyce Formation indicate a transgressive to dominated facies; (2) sandstone-dominated facies; regressive succession, from shallower to open sea and (3) olistostromal facies; (4a) rhythmic heterolithic back to shallower palaeoenvironments. facies of sandstone and mudstone; (4b) carbonate facies; (5) pure sandstone facies; (6) coarse clastic- conglomerate facies (Görmüş et al. 2001). Th e Sedimentological Overview last two facies are distinguished as separate units: Overall the Güneyce Formation contains primary the Gökdere Formation (Yalçın 1993). Th e total sedimentary structures typical of turbidity current thickness of the Güneyce Formation is between deposits. Th is chapter gives a generalised overview 500−750 m, according to our fi eld observations. Th e of these deposits. Th e divisions Ta, Tb, Tc, Td and underlying contact with the Karabayır Formation is Te by Bouma (1962) have been widely used to conformable and interfi ngering is present. Pliocene describe turbiditic beds (e.g., Komar 1985; Talling and Quaternary volcanic rocks rest unconformably 2001; Sinclair & Cowie 2003; Bouma 2004; Schultz on the Miocene sediments, as in the palaeovalley & Hubbard 2005; Warchoł & Leszczyński 2009). located 2 to 3 km south of Savköy. Walker (1978) and Mutti (1992) found the Bouma divisions to be insuffi cient for classifi cation of coarse- Microfossils and nannofossils of the Güneyce grained beds, which may contain a broad spectrum Formation are listed below. Details about nannofossils of sediment types. For detailed facies analysis with and their reworking are compiled from Görmüş et al. genetic facies, Mutti (1992) recommended that the (2001, 2004). Planktonic foraminifera: Globigerina broadly descriptive divisions of Bouma (1962), Mutti sp., Globigerinoides sp., Globorotalia sp., G. cf. kugleri, & Ricci Lucchi (1972) and Walker (1978) should be Globoquadrina dehiscens, reworked Morozovella abandoned. In the present study, we consider the aequa, M. angulata. Benthic foraminifera: Bouma divisions adequate to capture the common Amphistegina sp., Lepidocyclina (Eulepidina) sp., sediment types in the Güneyce Formation. Th e Lepidocylina (Nephrolepidina) sp., Miogypsina sp., formation contains relatively well-sorted sandstones Miogypsinoides sp. and Operculina sp. Nannofossils: with a tabular and tapered geometry, which Braarudosphaera