Preliminary results on the origin of dissolution pipes in coastal eolianites of Şile (İstanbul)

Yıl 2018, Sayı: 1, 67 - 79, 15.10.2018

Muhammed Zeynel Öztürk Çağlar Çakır Mustafa Avcıoğlu Topçu Ahmet Ertek Nabi Evren Ahmet Evren Erginal

Öz

The origin of cylindrical and cone-shaped dissolution pipes commonly observed on coastal eolianites at tropical and Mediterranean coasts is still under debate. Such unusual paleokarstic landforms have been first recognized on Turkey’s coasts at Doğancılı village to the west of Şile, İstanbul. Main aim of this study is explain physical properties and development model of these forms. Pipes are carved into cross-bedded laminae of 5 m-thick oolitic eolianites and forms are seen along cliff surface located northern part of the eolianite. Depth and perimeter of 45 pipes which are good condition are measured via ruler. Based on measurements of 45 dissolution pipes along sea-faced cliffs where they are preserved, pipes have the maximum upper diameter of 60 cm and depth of 460 cm. The depth of some pipes reaches the boundary with the underlying paleosol. The vertical shape of these holes are not apparently controlled by the cross bedded laminae. Variability in dimension of forms might represent differences in generation of pipe formation. Composite forms formed by combination of closely-spaced pipes verged into the sharp-edged blocks, i.e. pinnacle, as result of the removal of side walls. These weathered holes in eolianite dated to late MIS6 and early MIS5 might have formed during more humid conditions succeeding hotter and drier conditions, favoring the deposition and cementation of eolianite sands. The lack of calcarete within the dissolution pipes reveals nonoccurrence of arid stages during their formation. Consequently, dissolution pipes are likely the result of covered fossil (covered) karst caused by infiltrated waters having more acidity due to soil CO2. The vertical dissolution taking place on macro pores were possibly caused by the effects of infiltrated waters, passing from plant roots to preferred flow paths in vadose zone. 

Anahtar Kelimeler

Dissolution pipes, Vertical waethering, Eolianite, Şile

ŞİLE (İSTANBUL) EOLİNİTLERİNDEKİ ÇÖZÜNME BORULARININ KÖKENİ ÜZERİNE ÖN BULGULAR

Öz

Tropikal kıyılar ile Akdeniz kuşağı kıyılarındaki karbonat eolinitlerinde yaygın olarak gözlenen silindir ve konik şekilli dikey ayrışma borularının oluşumu halen tartışmalıdır. Bu tür nadir paleo-kıyı karstı şekilleri, Türkiye kıyılarından ilk kez Şile (İstanbul) batısındaki Doğancılı kıyı zonunda, 5 metre kalınlıktaki çapraz laminalı oolitik eolinit tabakaları içinde tespit edilmiştir. Bu çalışmanın temel amacı eolinit kütlesi içerisinde gelişmiş bu şekillerin fiziksel özelliklerinin ve gelişim modelinin ortaya konulmasıdır. Eolinitin kuzey kesimindeki falez yüzeyi boyunca çok fazla sayıda ayrışma borusu gelişmiştir. Bu şekillerden bozulmamış olan 45 tanesinden şerit metre yardımıyla derinlik, ve çap ölçümleri yapılmıştır. Ölçümlerine göre, çözünme borularının maksimum ağız çapı 60 cm ve derinliği 460 cm'dir.  Bazı şekillerde derinlik, eolinitin örttüğü paleosol katmanı ile olan dokanağa kadar yaklaşır. Şekiller çapraz tabakalı eolinit içerisinde gelişmiş olmakla birlikte dikey formları üzerinde çapraz laminasyonun kontrolü yoktur. Boyutlardaki değişkenlik, şekillerin oluşum evrelerinin farklılığı ile ilgili olmalıdır. Birbirine yakın gelişmiş olan çözünme borularının birleşmesiyle bileşik formlar oluşmuş, yan duvarların ortadan kalkması sonucu borular "pinnacle" denilen münferit keskin kenarlı bloklara dönüşmüşlerdir. Denizel izotop dönemi (MIS) 6 sonu ile MIS 5e başlarına tarihlendirilen eolinitler üzerinde gelişmiş bu şekiller, eoliyen kumlarının oluşumu ve çimentolanmasının gerçekleştiği daha sıcak ve kurak koşulları izleyen nemli koşullar altında gelişmiş olmalıdır. Borular içinde kalker kabuk gözlenmemesi, oluşumları esnasında kurak evrelerin yaşanmadığını açıklar. Sonuç olarak çözünme boruları organik maddece zengin topraktan derine sızan CO2 ile asitliği artmış suların yol açtığı erime sonucu fosil (örtülü) karst olarak gelişmiş olmalıdır. Çözünme yüzeyde bitki köklerinden vadoz zondaki tercihi akış kanallarına aktarılarak makro gözenekler boyunca derine ilerlemiştir.

Anahtar Kelimeler

Ayrışma boruları, Dikey ayrışma, Eolinit, Şile

Kaynakça

• Adams, R.A. (1983) General Guide to the Geological Features of San Salvador. In: Gerace, D. T. (ed.), Field Guide to The Geology of San Salvador, CCFL Bahamian Field Station, San Salvador, pp. 1-66.
• Baker, G. (1943) Features of a Victorian limestone coastline. Journal of Geology, 51 (6), 359-386.
• Baker, G. (1958) Stripped zonesat cliffedges alonga high wave energy coast, Port Campbell, Victoria. Proceedings of The Royal Society of Victoria, 70, 175-179.
• Bird, E. C. F. (1970) Shore potholes at Diamond Bay, Victoria. Victoria Naturalist, 87, 312-318.
• Brelz, J. H. (1960) Bermuda: A partially drowned, Late Mature, Pleistocene Karst. Bulletin of The Geological Society of America, 71 (12), 1729-1754.
• Brooke, B. (2001) The distribution of carbonate eolianite. Earth Science Reviews, 55 (1-2), 135-164.
• Brunsden, D., Doornkamp, J.C., Green, C.P. & Jones, D.K.C. (1976) Tertiary and Cretaceous sedimentsin solution pipes in the Devonian Limestone of South Devon. Geological Magazine, 113 (5), 441-447.
• Burnaby, T. P. (1950) The tubular chalk stacks of Sheringham. Proceedings of The Geological Association, 61 (4), 226-241.
• Carew, J. L. & Mylroie, J. E. (1994) Geology and Karst of San Salvador Island, Bahamas. A Field Trip Guidebook. Bahamian Field Station, San Salvador Island, Bahamas, pp. 32.
• Caron, V., Bernier, P. & Mahieux, G. (2009) Record of Late Pleistocene (Oxygen Isotopic Stage 5) climate changes during episodes of karst development on the Northern coast of Crete: Sequence stratigraphic implications. Palaeogeography, Palaeoclimatology, Palaeoecology, 277 (3-4), 246-264.
• Coetzee, F. (1975) Solution pipes in coastal aeolianites of Zululand and Mozambique. Transactions of The Geological Society of South Africa, 78, 323–333.
• Day, A.E. (1928) Pipes in the coast sandstone of Syria. Geological Magazine, 65 (9), 412–415.
• De Bruijn & R.G.M. (1983) Some considerations on the factors that influence the formation of solution pipes in chalk rock. Bulletin of The International Association of Engineering Geology, 28 (1), 141-146.
• De Waele, J., Mucedda, M. & Montanaro, L. (2009) Morphology and origin of coastal karst landforms in Miocene and Quaternary carbonate rocks along the central-western coast of Sardinia (Italy). Geomorphology, 106 (1-2), 26–34.
• De Waele, J., Lauritzen, S. E. & Parise, M. (2011) On the formation of dissolution pipes in Quaternary coastal calcareous arenites in Mediterranean settings. Earth Surface Processes and Landforms, 36 (2), 143–157.
• Erginal, A. E., Kıyak, N. G., Ekinci, Y.L., Demirci, A., Ertek, A. & Canel, T. (2013) Age, composition and paleoenvironmental significance of a late Pleistocene eolianite from the western Black Sea coast of Turkey. Quaternary International, 296, 168-175.
• Fairbridge, R.W. (1950) The geology and geomorphology of point peron, Western Australia. Journal of The Royal Society of Western Australia, 34, 35-72. Fedorov, P. V. (1978) Pleistotsen Ponto-Kaspiia (The Pleistocene of the Ponto-Caspian Region). Trudy Geologicheskogo Instituta Akademii Nauka SSSR, Nauka, Moscow.
• Ferland, M., Roy, P. & Murray-Wallace, C. (1995) Glacial lowstand deposits on the outer continental shelf of Southeastern Australia. Quaternary Research, 44 (2), 294–299.
• Frebourg, G., Hasler, C., Le Guern, P. & Davaud, E., (2008) Facies characteristics and diversity in carbonate eolianites. Facies, 54 (2), 175–191.
• Greenly, E. (1901) On sandstone pipes in the Carboniferous limestone at Dwlban Point. Geological Magazine, 7 (1), 20-24.
• Grimes, K. G. (2004) Solution pipes or petrified forests? Drifting sands and drifting opinions! The Victorian Naturalist, 121 (1), 14-22.
• Grimes, K. G. (2009) Solution pipes and pinnacles in syngenetic karst. In: Ginès, A. Knez, M., Slabe, T., Dreybrodt, W., (eds.) Karst Rock Features: Karren Sculpturing, Založba ZRC, Ljubljana, pp. 513-523.
• Herwitz, S.R. (1993) Stemflow influences on the formation of solution pipes in Bermuda eolianite. Geomorphology, 6 (3), 253-271.
• Jennings, J.N. (1968) Syngenetic karst in Australia. In: Williams, P. W., Jennings, J. N. (eds.) Contributions to the Study of Karst, Australian National University, Canberra, pp. 41–110.
• Jouzel, J., Lorius, C., Petit, J.R., Genthon, C., Barkov, N.I., Kotlyakov, V.M. & Petrov, V.M. (1987) Vostok ice core: a continuous isotope temperature record over the last climatic cycle (160,000 years). Nature, 329, 403-408.
• Lipar, M. (2009) Pinnacle syngenetic karst in Nambung National Park, Western Australia. Acta Carsologica, 38 (1), 41-50.
• Lipar, M., Webb, J.A., Whit, S.Q. & Grimes, K.G., (2015) The genesis of solution pipes: Evidence from theMiddle–Late Pleistocene Bridgewater Formation calcarenite, southeastern Australia. Geomorphology, 246, 90–103.
• Livingston, W. (1944) Observations on the structure of Bermuda. Geographical Journal, 104 (1-2), 40-48.
• Lowry, D.C. (1973) Origin of the Pinnacles, Nambung, WA: Australian Speleological Foundation Newsletter, 62, pp. 7–8.
• Lundberg, J. & Taggarf, B. E., 1995. Dissolution pipes in northern Puerto Rico: An exhumed paleokarst. Carbonates and Evaporites, 10 (2), 171-183.
• Marsico, A., Selleri, G., Mastronuzzi, G., Sansò, P. & Walsh, N. (2003) Cryptokarst: A case-study of the Quaternary landforms of Southern Apulia (Southern Italy). Acta Carsologica, 32 (2), 147-159.
• McLaren, S. (2004) Aeolianite. In: Andrew S. Goudie (ed.), Enclopedia of Geomorphology. Routledge, London, pp. 11-12.
• Morawiecka, I. (1993) Palaeokarst phenomena in the Pleistocene raised beach formations of the South West Peninsula of England. Preliminary report. Kras I Speleologia, 7, 79–91.
• Morawiecka, I. & Walsh, P. (1997) A study of solution pipes preserved in the Miocene limestones (Staszów, Poljska). Acta Carsologica, 26 (2), 337-350.
• Öztürk, M.Z., Çetinkaya, G., & Aydın, S. (2017) Köppen-Geiger iklim sınıflandırmasına göre Türkiye’nin iklim tipleri. Coğrafya Dergisi, 35, 17-27.
• Petrus, K. & Szymczak, P. (2015) Influence of layering on the formation and growth of solution pipes. Frontiers in Physics, 3, 92.
• Polymeris, G.S., Erginal, A. E. & Kiyak, N.G. (2012) A comparative morphological, compositional and TL study of Tenedos (Bozcaada) and Şile aeolianites, Turkey. Mediterranean Arhaeology and Archaeometry, 12 (2), 117-131
• Prouty, J.S. & Lovejoy, D.W. (1992) Remarkable cylindrical solution pipes in Coquina south of Baffin Bay, Texas. Transactions of the Gulf Coast Association of Geological Societies, 42, 599-606.
• Rabineau, M., Berne, S., Olivet, J. L., Aslanian, D., Guillocheau, F. & Joseph, P. (2006) Paleo sea levels reconsidered from direct observation of paleoshore-line position during glacial maxima (for the last 500,000 yr). Earth and Planetary Science Letters, 252 (1-2), 119–137.
• Rohling, E., Fenton, M., Bertrand, F., Ganssen, G. & Caulet, J. (1998) Magnitudes of sea level lowstands of the past 500,000 years. Nature, 394, 162–165.
• Rudnicki, J. (1980) Karst in coastal areas -development of karst processes in the zone of mixing of fresh and saline water (with special reference to Apulia, Southern Italy). Studia Geologica Polonica, 65, 9–59.
• Shackleton, N. (1987) Oxygen isotopes, ice volume and sea level. Quaternary Science Reviews, 6 (3-4), 183–190. Seyir, Hidrografi ve Oşinografi Dairesi (SHOD) 2000. İstanbul Boğazı-Kefken Arası Batimetri Haritası.
• Walkden, G. & Davis, J. (1983) Polyphase erosion of subaerial omission surfaces in the Late Dinantian of Anglesey, North Wales. Sedimentology, 30 (6), 861-878.
• Walsh, P. & Morawiecka, I. (2001) A dissolution pipe palaeokarst of mid-Pleistocene age preserved in Miocene limestones near Staszów, Poland. Palaeogeography, Palaeoclimatology, Palaeoecology, 174 (4), 327–350.
• Webb, G.E. (1994) Paleokarst, paleosol, and rocky-shore deposits at the Mississippian-Pennsylvanian unconformity, northwestern Arkansas. Geological Society of America Bulletin, 106 (5), 634-648.
• West, I. M. (1973) Carbonate cementation of some Pleistocene temperate marine sediments. Sedimentology, 20 (2), 229–249.
• Willems, L., Rodet, J., Fournier, M., Laignel, B., Dusar, M., Lagrou, D., Pouclet, A., Massei, N., Dussart-Baptista, L., Compere, P. & Ek, C. (2007) Polyphase karst system in Cretaceous chalk and calcarenite of the Belgian-Dutch border. Zeitschrift fur Geomorphologie, 51 (3), 361–376.
• Winguth, C., Wong, H. K., Panin, N., Dinu, C., Georgescu, P., Ungureanu, G., Krugliakov, V.V. & Podshuveit, V. (2000) Upper Quaternary water level history and sedimentation in the northwestern Black Sea. Marine Geology, 167 (1-2), 127–146.
• Wright, V.P. (1983) The polphase karstification of the Carboniferous Limestone in South Wales. In: Sweeting, M. M., Paterson, K. (eds.) New Trends in Karst Geomorphology. Geo-Abstracts, Norwich, pp. 569-580.
• Yehle, L.A. (1954) Soil tongues and their confusion with certain indicators of periglacial climate. American Journal of Science, 252 (9), 532–546.