Deep and shallow structures of large pockmarks in the Turkish shelf, Eastern Black Sea

Çifçi, Günay; Dondurur, Derman; Ergün, Mustafa

doi:10.1007/s00367-003-0138-x

Cited by 66 publications

(19 citation statements)

References 35 publications

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“…Under the gas front, the acoustic turbidity usually wipes out other coherent seismic signals completely or reduces their amplitudes (Judd and Sim 1998). Natural gas and/or overpressure fluid flow in near-surface sediments causes pockmarks which are crater-like features on the seafloor (e.g., Baraza and Ercilla 1996, Ergün et al 2002, Çifçi et al 2003, Gay et al 2006, Iglesias and García-Gil 2007, Judd and Hovland 2007, Savini et al 2009, Crutchley et al 2010, Valle and Gamberi 2011. The main agent responsible for the formation of these remarkable geological features is either ascending gas or fluid flow (King and MacLean 1970).…”

Section: Seismic Expression Of Shallow Gasmentioning

confidence: 96%

“…Considering the Turkish coastal seas, several gas bearing regions have been discovered in the Black Sea (Ergün et al 2002, Çifçi et al 2003, Dondurur 2005, Aegean Sea (Bange et al 1996, Dondurur et al 2011 as well as in the Sea of Marmara (Zitter et al 2008). The gas seepage and fluid escapes in the Sea of Marmara might have resulted from a combination of various factors, mostly associated with active tectonic features (Ritt et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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High-Resolution Seismic Characterization of Shallow Gas Accumulations in the Southern Shelf of Marmara Sea, Turkey

Vardar

Alpar

2016

Acta Geophys.

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A b s t r a c tHigh-resolution seismic survey was conducted to investigate acoustic characteristics of gassy sediments along the southern shelf of the Sea of Marmara. The acoustic turbidity zones outlined within the study area are generally below 2-9 m (2-10 ms TWT) the seafloor whilst this vertical distance varies between 9 and 21 m (10-25 ms TWT) for acoustic blanket type reflections. The gassy sediments cover an area of sea floor of about 45, 110, and 75 km 2 in front of Gönen River, Kocasu River, and Gemlik Bay, respectively. The gassy sediments in the center of Gemlik Bay exhibited an elliptical geometry similar to its basin while the others have deltaic forms in front of the rivers. The sea bottom and near surface sedimentary units are made-up of organic-rich sediments, mostly transported by the southern rivers. The gas observed in sediments is thought to be of biogenic origin, which may be caused by degradation of organic matter in the sediment.

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Section: Seismic Expression Of Shallow Gasmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

High-Resolution Seismic Characterization of Shallow Gas Accumulations in the Southern Shelf of Marmara Sea, Turkey

Vardar

Alpar

2016

Acta Geophys.

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“…Pockmarks have been discovered in many locations on ocean floors worldwide and at a range of depths from >1000 m in the abyssal ocean (Panieri et al, 2017;Pilcher & Argent, 2007) to much shallower settings on the continental shelf (<100 m), providing evidence of their wide bathymetric range. In European waters, gas/fluidescape related pockmarks have been identified from high-resolution bathymetry and geophysical data in all the shelf seas: in the Mediterranean (Marinaro et al, 2006), Black Sea (Çifi¸, Dondurur, & Ergün, 2003;Papatheodorou, Hasiotis, & Ferentinos, 1993), Baltic (Whiticar & Werner, 1981), Barents Sea (Hovland & Judd, 1988;Solheim & Elverhøi, 1993) and North Sea Basins (Gafeira & Long, 2015a;Judd & Hovland, 2007;Krämer et al, 2017). So far, no inventory or detailed studies have been conducted of pockmarks in Scottish fjords or the adjacent shelf seas west of the UK.…”

Section: Introductionmentioning

confidence: 99%

Distribution and classification of pockmarks on the seabed around western Scotland

et al. 2019

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Pockmarks are seabed depressions that represent primary evidence of rapid biogenic/ thermogenic gas build up and fluid release from seabed sediments to the water column. We use a Geographical Information System (GIS) to analyse multibeam echo-sounder bathymetric data and use a range of semi-automated tools to map seabed pockmarks in fjords and adjacent coastal waters around western Scotland. We map 1019 individual pockmarks in 12 different hydrographic areas covering ca. 2019 km 2 . We use morphological metrics and statistical procedures to classify and analyse the variety of pockmark forms. A kmeans clustering algorithm identifies three classes of pockmark morphology: deep, elongate and regular. The recognition of separate pockmark classes could aid understanding of their age, activity and origin. This work presents the first detailed mapping of pockmark fields in Scottish west coast waters and highlights the use of pockmarks as an indicator of the quantity, mobility and fate of stored carbon. ARTICLE HISTORY

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“…1) by Driscoll et al [2000]. While the usual scale of pockmarks ranges from a few meters to ~300 m in diameter and up to 25 m in relief [Christodoulou et al, 2003, Çifçi et al, 2003, these shelf-edge features are several kilometers long, up to a kilometer across and 50 m in relief. Until these pockmarks were discovered, pockmarks exceeding 350 m in diameter and 35 m in relief were classified as "giant" [Kelley et al, 1994].…”

Section: Introductionmentioning

confidence: 99%

Active methane venting observed at giant pockmarks along the U.S. mid-Atlantic shelf break

Newman

Cormier

Weissel

et al. 2008

Earth and Planetary Science Letters

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(concentrations above open ocean background), combined with water column salinity and 2 temperature vertical profiles, indicate that methane-rich water is not present across the entire width of the pockmarks, but is laterally restricted to their edges. We suggest that venting is primarily along the top of the pockmark walls with some advection and dispersion due to local currents. The highest methane concentrations observed with the METS sensor occur at a small, circular pockmark at the southern end of the study area.This observation is compatible with a scenario where the larger, elongate pockmarks evolve through coalescing smaller pockmarks.

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Deep and shallow structures of large pockmarks in the Turkish shelf, Eastern Black Sea

Cited by 66 publications

References 35 publications

High-Resolution Seismic Characterization of Shallow Gas Accumulations in the Southern Shelf of Marmara Sea, Turkey

High-Resolution Seismic Characterization of Shallow Gas Accumulations in the Southern Shelf of Marmara Sea, Turkey

Distribution and classification of pockmarks on the seabed around western Scotland

Active methane venting observed at giant pockmarks along the U.S. mid-Atlantic shelf break

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