Ayhan ILGAR, Ali ERGEN, Ercan TUNCAY, Alper BOZKURT

Basin margin tectonics and morphology as controls of delta type and architecture: examples from the Mio-Pliocene Yalvaç Basin (SW Turkey)

This study describes the sedimentary facies and depositional architectures of Gilbert-type and shoal-water delta deposits developed on opposed margins of the extensional fluvio-lacustrine Yalvaç Basin during the late Cenozoic. The roles of syndepositional tectonism, basin dynamics, and hinterland morphology on the development of different delta types are assessed. This asymmetric trough initially opened as an intramontane molasse basin to the southwest of the Sultandağları massif. Its northern and southern margins are bounded by normal faults, which controlled both tectono-sedimentary evolution of the basin and the surrounding palaeomorphology. The lacustrine deposits consist of thin-bedded limestones, marls, and medium to thick-bedded sandstones and conglomerates. The coarse-grained Gilbert-type delta, up to 150 m thick, was deposited just in the front of the steep northern basin margin. The clinoformal architecture of this delta comprises steeply inclined foreset beds, which are overlain by horizontal alluvial topset units and underlain by subhorizontal bottomset deposits. The Yarıkkaya normal fault controls the northern margin of the basin and plays an active role in both local uplift and subsidence, giving rise to new sediment sources and increasing the accommodation space. Abundant coarse-grained sediment supply into this relatively deep basin across the steep scarp of the Yarıkkaya Fault led to creation of a delta with Gilbert-type architecture. Contemporaneously, on the shallow southern margin of the Yalvaç Basin, several small shoal-water deltas up to 3.5 m thick, were deposited on a smooth basin floor. The gently mound-shaped depositional architecture of these shoal-water delta deposits comprise erosive-based mouth-bar and distributary channel deposits. These observations show that, in this case, the river deposited its bedload shortly after entering the basin, generating small shoal-water deltas that, through stacking over time and some lateral offset, built a shoal-water delta complex.

PDF

___

Akıska E, Varol BE (2020). Alluvial-lacustrine sedimentation and volcaniclastic deposition in an intracontinental tectonic graben: paleoenvironmental evolution of the Neogene Sinanpaşa Basin, west-central Turkey. Turkish Journal of Earth Sciences 29 (2): 295-324. doi: 10.3906/yer-1907-28
Alexander J, Leeder MR (1987). Active tectonic control on alluvial architecture. In: Ethridge FG, Flores RM, Harvey MD (editors). Recent Developments in Fluvial Sedimentology. Tulsa, OK, USA: Society of Economic Paleontologists and Mineralogists Special Publications, pp. 243-252.
Barrell J (1912). Criteria for the recognition of ancient delta deposits. Bulletin of the Geological Society of America 23: 377-446.
Bhattacharya JP (2010). Deltas. In: James NP, Dalrymple RW (editors). Facies Models 4. 1st ed. Canada: Geological Association of Canada, Geotext 6, pp. 233-264.
Bluck BJ (1967). Sedimentation of beach gravels: examples from South Wales. Journal of Sedimentary Petrology 37: 128-156.
Bluck BJ (1999). Clast assemblages, bed-forms and structure in gravel beaches. Transactions of the Royal Society of Edinburgh Earth Sciences 89: 291-332.
Bornhold BD, Prior DB (1990). Morphology and sedimentary processes of the subaqueous Noeick River delta, British Columbia, Canada. In: Colella A, Prior DB (editors). CoarseGrained Deltas. London, UK: International Association of Sedimentologists Special Publications, pp. 169-181.
Clausing A (1990). Mikrofazies lakustriner Karbonat-horizonte des Saar-Nahe-Beckens (Unterperm, Rotliegend, SWDeutschland). Facies 23: 121-140.
Colella A, Prior DB (editors) (1990). Coarse-Grained Deltas. International Association of Sedimentologists Special Publications 10. 1st ed. London, UK: Blackwell Scientific Publications.
Colella A (1988). Pliocene–Holocene fan deltas and braid deltas in the Crati Basin, southern Italy: a consequence of varying tectonic conditions. In: Nemec W, Steel RJ (editors). Fan Deltas–Sedimentology and Tectonic Settings. London, UK: Blackie, pp. 50-74.
Collinson JD (1996). Alluvial sediments. In: Reading HG (editor). Sedimentary Environments: Processes, Facies and Stratigraphy. 1st ed. Oxford, UK: Blackwell Publishing, pp. 37-82.
Demirkol C (1982). Yalvaç-Akşehir dolayının stratigrafisi ve Batı Toroslarla deneştirimi. Jeoloji Mühendisliği 14: 3-14 (in Turkish with English abstract).
Demirkol C, Sipahi H, Barka A, Sönmez Ş, Çiçek S (1977). Sultandağı’nın stratigrafisi ve jeolojik evrimi. General Directorate of Mineral Research and Exploration (MTA), Report No: 6305. Ankara, Turkey: MTA (in Turkish).
Demirkol C, Yetiş C (1983-1984). Hoyran Gölü (Isparta) kuzeyinin stratigrafisi. Maden Tetkik ve Arama Dergisi 101-102: 1-13 (in Turkish with English abstract).
Dunne LA, Hempton MR (1984). Deltaic sedimentation in the Lake Hazar pull-apart basin, South-eastern Turkey. Sedimentology 31: 401-412.
Elliott T (1986). Deltas. In: Reading HG (editor). Sedimentary Environments: Processes, Facies and Stratigraphy. 1st ed. Oxford, UK: Blackwell Publishing, pp. 113-154.
Ergen A, Bozkurt A, Ilgar A, Tuncay E, Doğan A (2021). Sultandağları’nın Jeolojisi ve Jeodinamik Evrimi. MTA Report No: 13958. Ankara, Turkey: MTA (in Turkish).
Gawthorpe RL, Colella A (1990). Tectonic controls on coarse-grained delta depositional systems in rift basins. In: Colella A, Prior DB (editors). Coarse-Grained Deltas. London, UK: International Association of Sedimentologists Special Publications, pp. 113- 128.
Gawthorpe RL, Leeder MR (2000). Tectono-sedimentary evolution of active extensional basins. Basin Research 12: 195-218.
Ghinassi M (2007). The effects of differential subsidence and coastal topography on high-order transgressive-regressive cycles: Pliocene nearshore deposits of the Val d’Orcia Basin, Northern Apennines, Italy. Sedimentary Geology 202: 677-701.
Gutnic M, Keller D, Monod O (1968). Decouverte de nappes de charriage dans le nord du Taurus occidental (Turquie mSridionale). Comptes rendus de l’Académie des Sciences 226: 988-901.
Ilgar A (2015). Miocene sea-level changes in northernmost Anatolia: Sedimentary record of eustasy and tectonism at the periPontide fringe of Eastern Paratethys. Sedimentary Geology 316: 62-79. doi: 10.1016/j.sedgeo.2014.11.006
Ilgar A, Nemec W (2005). Early Miocene lacustrine deposits and sequence stratigraphy of the Ermenek Basin, Central Taurides, Turkey. Sedimentary Geology 173: 217-249.
Koç A, Kaymakci N, van Hinsbergen DJJ, Vissers RLM (2014). A Miocene onset of the modern extensional regime in the Isparta Angle: constraints from the Yalvaç Basin (southwest Turkey). International Journal of Earth Sciences (Geol Rundsch) 105: 369-398. doi: 10.1007/s00531-014-1100-z
Koçyiğit A, Deveci Ş (2007). A N–S-trending active extensional structure, the Şuhut (Afyon) Graben: commencement age of the extensional neotectonic period in the Isparta Angle, SW Turkey. Turkish Journal of Earth Sciences 16: 391-416.
Koçyiğit A, Gürboğa Ş, Kalafat D (2013). Nature and onset of neotectonic regime in the northern core of Isparta Angle, SW Turkey. Geodinamica Acta 25 (1-2): 52-85.
Leeder MR, Gawthorpe RL (1987). Sedimentary models for extensional tilt-block/half-graben basins. In: Coward MP, Dewey JF, Hancock PL (editors). Continental Extensional Tectonics. London, UK: Geological Society of London Special Publications, pp. 139-152.
Leeder MR, Ord, DM, Collier R (1988). Development of alluvial fans and fan deltas in neotectonic settings: implications for the interpretations of basin fills. In: Nemec W, Steel RJ (editors). Fan Deltas–Sedimentology and Tectonic Settings. London, UK: Blackie, pp. 173-185.
Leszczyński S, Nemec W (2014). Dynamic stratigraphy of peripheral composite unconformity in a foredeep basin. Sedimentology 62 (3): 645-680. doi: 10.1111/sed.12155
Lowe DR (1982). Sediment gravity flows: II. Depositional models with special reference to the deposits of high-density turbidity currents. Journal of Sedimentary Petrology 52: 279-297.
Miall AD (1985). Architectural-element analysis: a new method of facies analysis applied to fluvial deposits. Earth-Science Reviews 22: 261-308.
Miall AD (1996). The Geology of Fluvial Deposits. 1st ed. Heidelberg, Germany: Springer-Verlag.
Monod O (1977). Récherches géologiques dans le Taurus occidentalau sud de Beyşehir (Turquie). PhD, Université de Paris Sud, Orsay, Paris, France (in French).
Nemec W (1990). Aspects of sediment movement on steep delta slopes. In: Colella A, Prior DB (editors). Coarse-Grained Deltas. London, UK: International Association of Sedimentologists Special Publications, pp. 29-73.
Nemec W, Postma G (1993). Quaternary alluvial fans in southwestern Crete: sedimentation processes and geomorphic evolution. In: Marzo M, Puigdefabregas C. (editors). Alluvial Sedimentation. Ghent, Belgium: International Association of Sedimentologists Special Publications, pp. 235-276.
Nemec W, Steel RJ (1984). Alluvial and coastal conglomerates: their significant features and some comments on gravelly massflow deposits. In: Koster EH, Steel RJ (editors). Sedimentology of Gravels and Conglomerates. Ottawa, Canada: Canadian Society of Petroleum Geologists Memoirs, pp. 1-31.
Oti MN, Postma G (editors) (1995). Geology of Deltas. 1st ed. Rotterdam, the Netherlands: CRC Press.
Özgül N, Bölükbaşı S, Alkan H, Öztaş Y, Korucu M (1991). Sultandağları-Sandıklı-Homa-Akdağ yöresinin jeolojisi. Turkish Petroleum (TPAO) Archive Report No: 3028, Ankara, Turkey: TPAO (in Turkish).
Postma G (1990). Depositional architecture and facies of river and fan deltas: a synthesis. In: Colella A, Prior DB (editors). CoarseGrained Deltas. London, UK: International Association of Sedimentologists Special Publications, pp. 13-27.
Postma G (1995). Causes of architectural variation in coarse-grained deltas. In: Oti M, Postma G (editors). The Geology of Deltas. Rotterdam, the Netherlands: CRC Press, pp. 1-16.
Sohn YK, Son M (2004). Synrift stratigraphic geometry in a transfer zone coarse-grained delta complex, Miocene Pohang Basin, SE Korea. Sedimentology 51: 1387-1408.
Şenel M, Dalkılıç H, Gedik İ, Serdaroğlu M, Bölükbaşı AS et al. (1992). Eğirdir-Yenişarbademli, Gebiz ve Geriş-Köprülü (Isparta-Antalya) arasında kalan alanların jeolojisi: General Directorate of Mineral Research and Exploration (MTA) Report No: 9390. Ankara, Turkey: MTA (in Turkish).
Tuncer A (2020). Yalvaç ve Ilgın karasal Neojen havzalarında (Güneybatı Anadolu) Ostracoda taksonomisi ve biyostratigrafisi: Ostrakodlara dayalı eskiortamsal-eskiiklimsel yaklaşımlar. PhD, Hacettepe University, Ankara, Turkey (in Turkish with English abstract).
Usta NDY, Mayda S, Kaya TT (2019). Yeni buluntular ışığında Yalvaç (Isparta / Türkiye) Neojen devir omurgalı fosil yatakları. SDÜ Fen-Edebiyat Fakültesi Sosyal Bilimler Dergisi 47/2: 79-96 (in Turkish).
Wood ML, Ethridge FG (1988). Sedimentology and architecture of Gilbert- and mouth bar-type fan deltas, Paradox Basin, Colorado. In: Nemec W, Steel RJ (editors). Fan Deltas– Sedimentology and Tectonic Settings. London, UK: Blackie, pp. 251-263.
Wright LD (1977). Sediment transport and deposition at river mouths: a synthesis. Bulletin of the Geological Society of America 88: 857-868.
Yağmurlu F (1991). Yalvaç-Yarıkkaya Neojen Havzasının stratigrafisi ve depolanma ortamları. Türkiye Jeoloji Bülteni 34: 9-19 (in Turkish).