Naci GÖRÜR, Şebnem ÖNDER, Alina POLONIA, Luca GASPERINI

Fault-controlled gas escapes in the shelf sediments of the Saros Gulf, NE Aegean Sea

High-resolution marine seismic reflection studies on the eastern shelf of the Saros Gulf have revealed the presence of gascharged sediments across a narrow submarine valley incised by the Ganos Fault along the North Anatolian Fault system. Quaternary sediments, accumulated during glacial and interglacial periods through transgressional and progradational units, were controlled by glacio-eustatic sea-level fluctuations and tectonic deformation. The transgressional units made of upward-fining deposits created seals at their tops to form gas accumulation pockets. Conversely, the progradational units appear heavily eroded at their top, which is unfavorable for gas accumulation. The sediment’s gas accumulation features include enhanced reflections, acoustic blanking (or blanket), acoustic turbidity, acoustic curtain, and acoustic columns. In contrast, the gas escape features consist of acoustic plumes, cloudy turbidity, domes, and pockmarks. Their concentration along the Ganos Fault indicates that active deformation, punctuated by large magnitude earthquakes, has played an essential role in their formation, storage, and seep. Understanding these interactions may provide valuable contributions to hydrocarbon explorations and early-warning strategies against earthquake risk.

PDF

___

Aksoy ME, Meghraoui M, Vallée M, Çakır Z (2010). Rupture characteristics of the A.D. 1912 Mürefte (Ganos) earthquake segment of the North Anatolian fault (western Turkey). Geology 38: 991–994. doi: 10.1130/G31447.1.
Aksoy ME (2021). The 9 August 1912 Mürefte-Şarköy earthquake of the North Anatolian Fault. Mediterranean Geoscience Reviews 3: 95-114.
Aksu AE, Piper DJW, Konuk T (1987b). Quaternary growth patterns of the Büyük Menderes and Küçük Mederes Deltas, Western Turkey. Marine Geology 76: 89-104.
Alpar B, Yaltırak C (2002). Characteristic features of the North Anatolian Fault in the eastern Marmara region and its tectonic evolution. Marine Geology 190 (1–2): 329-350.
Amante C, Eakins BW (2009). ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis. NOAA Tech. Memo. NESDIS NGDC-24 19. Colorado, USA: NOAA. doi: 10.1594/ PANGAEA. 769615
Berckhemer H (1977). Some aspects of the evolution of marginal seas deduced from observations in the Aegean region. In: Biju-Duval B, Montadert L (editors). International Symposium on the Structural History of the Mediterranean Basins. Split, Yugoslavia. pp. 303-314.
Bourry C, Chazallon B, Charlou JL, Donval JP, Ruffine L et al. (2009). Free gas and gas hydrates from the Sea of Marmara, Turkey: Chemical and structural characterization. Chemical Geology 264 (1-4): 197-206. doi: 10.1016/j.chemgeo.2009.03.007
Çağatay MN, Görür N, Alpar B, Saatçılar R, Akkök R et al. (1998). Geological evolution of the Gulf of Saros, NE Aegean Sea. GeoMarine Letters 1: 1–9. doi: 10.1007/s003670050045
Davatzes NC, Aydın A (2003). Overprinting faulting mechanisms in high porosity sandstones of SE Utah. Journal of Structural Geology 25: 1795–1813. doi: 10.1016/S0191-8141(03)00043-9
Dewey JF, Şengör AMC (1979). Aegean and surrounding regions: Complex multiplate and continuum tectonics in a convergent zone. GSA Bulletin 90 (1): 84–92. doi: 10.1130/0016-7606(1979)90<84:AASRCM>2.0.CO;2
Dupré S, Scalabrin C, Grall C, Augustin JM, Henry P et al. (2015). Tectonic and sedimentary controls on widespread gas emissions in the Sea of Marmara: Results from systematic, shipborne multibeam echo sounder water column imaging. Journal of Geophysical Research: Solid Earth 120: 2891– 2912. doi: 10.1002/2014JB011617
Embriaco D, Marinaro G, Frugoni F, Monna S, Etiope G et al. (2013). Monitoring of gas and seismic energy release by multiparametric benthic observatory along the North Anatolian Fault in the Sea of Marmara (NW Turkey). Geophysical Journal International 196 (2): 850-866.
Emre Ö, Duman TY, Özalp S, Elmacı H, Olgun S, Şaroğlu F (2013). Active fault map of Turkey with an explanatory text 1:1,250,000 scale. Special Publication Series 30. Ankara, Turkey: General Directorate of Mineral Research and Exploration.
Eriş KK (2007). Middle Pleistocene to recent sea level changes in the Sea of Marmara. PhD, İstanbul Technical University, İstanbul, Turkey (in Turkish with English abstract).
Erol O, Çetin O (1995). Marmara Denizi’nin Geç MiyosenHolosen’deki evrimi. In: Meriç E (editor). İzmit Körfezi Kuvaterner İstifi. Deniz Harp Okulu Komutanlığı Basımevi, İstanbul, Turkey. pp. 314-341.
Fannin NGT (1980). The use of regional geological surveys in the North Sea and adjacent areas in the recognition of offshore hazards. In: Ardus DA (editor). Offshore Site Investigation. London, United Kingdom: Graham and Trotman, pp. 5–22.
Floodgate GD, Judd AG (1992). The origins of shallow gas. Continental Shelf Research 12 (10): 1145–1156. doi: 10.1016/0278-4343(92)90075-U
Gasperini L, Stanghellini G (2009). SeisPrho: An interactive computer program for processing and interpretation of high-resolution seismic reflection profiles. Computers & Geosciences 35: 1497–1507. doi: 10.1016/j.cageo.2008.04.014
Gasperini L, Polonia A, Çağatay N, Bortoluzzi G, Ferrante V (2011). Geological slip rates along the North Anatolian Fault in the Marmara region. Tectonics 30:1-14 TC6001. doi:10.1029/2011TC002906, 2011
Gasperini L, Polonia, A, Del Bianco F, Etiope, G, Marinaro G et al. (2012). Gas seepage and seismogenic structures along the North Anatolian Fault in the eastern Sea of Marmara. Geochemistry, Geophysics, Geosystems 13 (10): 1-19.
Gasperini L, Aksoy E, Polonia A, Meghraoui M, Bianco F Del (2013). Geology and seismotectonics of the Gulf of Saros (NE Aegean Sea) along the seismotectonics of the Gulf of Saros (NE Aegean Sea) along the North-Anatolian Fault system. In: EGU General Assembly; Vienna, Austria. p.10180.
Gasperini L, Polonia A, Çağatay MN (2018). Fluid flow, deformation rates and the submarine record of major earthquakes in the Sea of Marmara, along the North-Anatolian Fault system. Deep Sea Research Part II: Topical Studies in Oceanography 153: 4–16. doi: 10.1016/j.dsr2.2018.03.004
Geli L, Henry P, Zitter T, Dupré S, Tryon M et al. (2008). Gas emissions and active tectonics within the submerged section of the North Anatolian Fault zone in the Sea of Marmara. Earth and Planetary Science Letters 274: 34-39.
Görür N, Okay AI (1996). A fore-arc origin for the Thrace Basin, NW Turkey. Geologische Rundschau 85: 662–668. doi: 10.1007/ BF02440103
Görür N, Elbek Ş (2013). Tectonic events responsible for shaping the Sea of Marmara and its surrounding region. Geodinamica Acta 26:1–11. doi: 10.1080/09853111.2013. 859346
Görür N, Çagatay MN (2010). Geohazards rooted from the northern margin of the Sea of Marmara since the late Pleistocene: A review of recent results. Natural Hazards 54: 583–603. doi: 10.1007/s11069-009-9469-x
Hatem AE, Cooke M, Toeneboehn K (2017). Strain localization and evolving kinematic efficiency of initiating strike-slip faults within wet kaolin experiments. Journal of Structural Geology 101: 96–108. doi: 10.1016/j.jsg.2017.06.011
Jarvis A, Reuter HI, Nelson A, Guevara E (2008). Hole-filled SRTM for the globe version 3, from the CGIAR-CSI SRTM 90m database. CGIAR-CSI Consortium for Spatial Information.
Konca AÖ, Çetin S, Karabulut H, Reilinger R, Doğan U (2018). The 2014, Mw6.9 North Aegean earthquake: seismic and geodetic evidence for coseismic slip on persistent asperities. Geophysical Journal International 213: 1113-1120.
Kurt H, Demirbag E, Kuşçu I (2000). Active submarine tectonism and formation of the Gulf of Saros, Northeast Aegean Sea, inferred from multi-channel seismic reflection data. Marine Geology 165: 13–26. doi: 10.1016/S0025-3227(00)00005-0
Le Pichon X, Angelier J (1979). The Hellenic arc and trench system: A key to the neotectonic evolution of the eastern mediterranean area. Tectonophysics 60 (1-2): 1-42. doi: 10.1016/0040- 1951(79)90131-8
Le Pichon X, Angelier J (1981). The Aegean Sea. Philosophical Transactions of the Royal Society of London. Series A. Mathematical and Physical Sciences 300 (1454): 357-372.
Myers R, Aydın A (2004). The evolution of faults formed by shearing across joint zones in sandstone. Journal of Structural Geology 26: 947– 966.
Polonia A, Gasperini L, Amorosi A, Bonatti E, Cağatay N et al. (2004). Holocene Slip rate of the North Anatolian Fault beneath the Sea of Marmara. Earth and Planetary Science Letters 427: 411- 426.
Saner S (1985). Saros Körfezi dolayının çökelme istifleri ve tektonik yerleşimi, Kuzeydoğu Ege Denizi, Türkiye. Türkiye Jeoloji Kurumu Bülteni: 1–10 (in Turkish).
Sarı E, Çağatay M (2001). Distributions of heavy metals in the surface sediments of the Gulf of Saros, NE Aegean Sea. Environment International 26 (3): 169–173. doi: 10.1016/ S0160-4120(00)00097-0
Seyitoğlu G, Scott BC (1991). Age of the Alaşehir graben (West Turkey) and its tectonic implications. Geological Journal 31: 1-11.
Shackleton NJ, Opdyke ND (1973). Oxygen isotope and paleomagnetic stratigraphy of equatorial Pacific Core V28- 238: oxygen isotope temperatures and ice volume on a 105 year and 106 year scale. Quaternary Research 3: 39-55. doi: 10.1016/0033-5894(73)90052-5
Siyako M, Burkan KA, Okay A (1989). Tertiary geology and hydrocarbon potential of the Biga and Gelibolu Peninsulas (in Turkish with English abstract). TAPG Bulletin 1 (3): 183–200.
Sümengen M, Terlemez İ, Şentürk K, Karaköse C, Erkan E et al. (1987). Gelibolu Yarımadası ve Güneybatı Trakya Tersiyer Havzası’ nın stratigrafisi, sedimantolojisi ve tektoniği (in Turkish). The Mineral Research and Exploration 8128. Ankara, Turkey: General Directorate of Mineral Explaration and Research of Turkey.
Şengör AMC (1982). Ege’nin neotektonik evrimini yöneten etkenler (in Turkish). In: Erol O, Oygür V (editors). Batı Anadolu’nun genç tektoniği ve volkanizması. Ankara, Turkey: Congress of the Geological Society of Turkey Publications, pp. 59-72.
Şengör AMC, Görür N, Şaroğlu F (1985). Strike-slip faulting and related basin formation in zones of tectonic escape: Turkey as a case ctudy. In: Biddle KT, Christie-Blick N (editors). StrikeSlip Deformation, Basin Formation, and Sedimentation. 10. New York, USA: Society of Economic Paleontologists and Mineralogists Special Publication, pp. 227–264.
Şengör AMC, Tüysüz O, İmren C, Sakınç M, Eyidoğan H et al. (2005). The North Anatolian Fault: A new look. Annual Review of Earth and Planetary Sciences 33 (1): 37-112.
Şengor AMC, Zabcı C, Natalin B (2019). Continental Transform Faults: Congruence and Incongruence with normal plate kinematics. In: Duarte João C (editor). Transform Plate Boundaries and Fracture Zones. Amsterdam, Netherlands: Elsevier, pp. 169-247.
Tchalenco JS (1970). Similarities between shear zones of different magnitudes. Geological Society of America Bulletin 81: 1625– 1640.
Taymaz T, Jackson J, Mckenzie D (1991). Active tectonics of the north and central Aegean Sea. Geophysical Journal International 106 (2): 433-490.
Tüysüz O, Barka A, Yiğitbaş E (1998). Geology of the Saros graben and its implications for the evolution of the North Anatolian Fault in the Ganos – Saros region, northwestern Turkey. Tectonophysics 293: 105–126.
Ustaömer T, Gökaşan E, Tur H, Görüm T, Batuk FG et al. (2008). Faulting, mass-wasting and deposition in an active dextral shear zone, the Gulf of Saros and the NE Aegean Sea, NW Turkey. Geo-Marine Letter 28: 171–193. doi: 10.1007/s00367-007-0099- 6
van Andel TH, Lianos N (1984). High-resolution seismic reflection profiles for the reconstruction of postglacial transgressive shorelines: An example from Greece. Quaternary Research 22 (1): 31-45. doi: 10.1016/0033-5894(84)90004-8
Yaltırak C (1995). Gaziköy - Mürefte (Tekirdağ) arasının sedimanter ve tektonik özellikleri (in Turkish). TPJD Bülteni 6 (1): 93-112. Yaltırak C (1996). Ganos Fay Sistemi’nin tektonik tarihi (in Turkish). TPJD Bülteni 8(1):137-156.
Yolsal- Çevikbilen S, Taymaz T (2012). Earthquake source parameters along the Hellenic subduction zone and numerical simulations of historical tsunamis in the Eastern Mediterranean. Tectonophysics 536–537: 61–100. doi: 10.1016/ j.tecto. 2012.02. 019