Methane-derived carbonates and authigenic pyrite from the northwestern Black Sea

Peckmann, Jörn; Reimer, Andreas; Luth, Ulf; Luth, Claudia; Hansen, Bent; Heinicke, C; Hoefs, Jochen; Reitner, Joachim

doi:10.1016/s0025-3227(01)00128-1

Cited by 426 publications

(334 citation statements)

References 70 publications

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“…4.1.A.). The region is wellknown for abundant gas seeps, carbonate buildups and shallow gas (Polikarpov et al, 1989;Polikarpov et al, 1992;Egorov et al, 1998;Luth et al, 1999;Peckmann et al, 2001;Thiel et al, 2001;Amouroux et al, 2002;Michaelis et al, 2002;Kruglyakova et al, 2004;Kutas et al, 2004;Popescu et al, 2004;Pape et al, 2005;Pimenov and Ivanova, 2005;Reitner et al, 2005;Schmale et al, 2005;Treude et al, 2005;McGinnis et al, 2006;Naudts et al, 2006). During the 58 th (May-June 2003) and 60 th (MayJune 2004) cruise of R.V.…”

Section: Study Areamentioning

confidence: 99%

“…The initial gas composition of the bubbles was almost pure methane (80 to 90 %) of presumed microbial origin as indicated by the isotopic composition (-62 to -68 13 C‰ PDB) (McGinnis et al, 2006). Peckmann et al (2001) assumes that the methane originates from organic-rich lacustrine sediments deposited during the Black Sea's fresh-water phase. (Egorov et al, 1998;Naudts et al, 2006).…”

Section: Study Areamentioning

confidence: 99%

“…AOM is typically associated with the formation of methane-derived authigenic carbonates (MDACs) (Hovland et al, 1985;Paull et al, 1992;Peckmann et al, 2001;Greinert et al, 2002a;Orange et al, 2002;Johnson et al, 2003;Mazzini et al, 2006;Judd and Hovland, 2007). Once MDAC formation has started, ongoing precipitation may result in clogging fluid pathways and also blocking the migration of free gas through the sediments, thus forcing bubbles to migrate laterally towards the edge of the carbonate crust or carbonate-cemented sediments.…”

Section: Bacterial Mats Carbonates and Their Relation To Seep Distrimentioning

confidence: 99%

“…High-acoustic backscatter is caused by the enhanced acoustic impedance or roughness contrast between certain regions of the seafloor and their surroundings (Blondel and Murton, 1997). At methane seeps, this contrast is primarily caused by the presence of methane-derived authigenic carbonates (MDACs), chemosynthetic "cold seep" communities (clams, tube worms), bubbles or gas hydrates in the sediment (Hovland et al, 1985;Ritger et al, 1987;Paull et al, 1992;von Rad et al, 1996;Greinert et al, 2001;Peckmann et al, 2001;Fonseca et al, 2002;Greinert et al, 2002b;Orange et al, 2002;Johnson et al, 2003;Niemann et al, 2005;Holland et al, 2006;Ivanov et al, 2007). Multibeam and side scan sonar surveys also detect changes in the seafloor morphology, which can mark the location of gas seeps (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

et al. 2008

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The relation between acoustic seafloor backscatter and seep distribution is examined by integrating multibeam backscatter data and seep locations detected by single-beam echosounder. This study is further supported by side scan sonar recordings, high-resolution 5 kHz seismic data, pore-water analysis, grain-size analysis and visual seafloor observations. The datasets were acquired during the 2003 and 2004 expeditions of the EC-funded CRIMEA project in the Dnepr paleo-delta area, northwestern Black Sea.More than 600 active methane seeps were hydro-acoustically detected within a small (3.96 km by 3.72 km) area on the continental shelf of the Dnepr paleo-delta in water depths ranging from -72 m to -156 m. Multibeam and side scan sonar recordings show backscatter patterns that are clearly associated with seepage or with a present dune area. Seeps generally occur within medium-to highbackscatter areas which often coincide with pockmarks.High-resolution seismic data reveal the presence of an undulating gas front, i.e. the top of the free gas in the subsurface, which domes up towards and intersects the seafloor at locations where gas seeps and medium-to high-backscatter values are detected. Pore-water analysis of 4 multi-cores, taken at different backscatter intensity sites, shows a clear correlation between backscatter intensity and dissolved methane fluxes. All analyzed chemical species indicate increasing anaerobic oxidation of methane (AOM) from medium-to high-backscatter locations. This is confirmed by visual seafloor observations, showing bacterial mats and authigenic carbonates formed by AOM. Grain-size analysis of the 4 multi-cores only reveals negligible variations between the different backscatter sites.Integration of all datasets leads to the conclusion that the observed backscatter patterns are the result of ongoing methane seepage and the precipitation of methane-derived authigenic carbonates (MDACs) caused by AOM. The carbonate formation also appears to lead to a gradual (self-)sealing of the seeps by cementing fluid pathways/horizons followed by a relocation of the bubble-releasing locations. KeywordsMethane seeps; acoustic seafloor backscatter; anaerobic oxidation of methane; bacterial mats; pockmarks; methane-derived authigenic carbonates

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Bacterial Mats Carbonates and Their Relation To Seep Distrimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

et al. 2008

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“…Although authigenic calcite and aragonite have commonly been used for geochemical characterization of seeping fluids and paleoenvironmental reconstruction at recent (e.g., Himmler et al, 2010;Peckmann et al, 2001;Peckmann and Thiel, 2004;Capozzi et al, 2012;Magalhães et al, 2012) and fossil (e.g., Blumenberg et al, 2015;Cau et al, 2015;Viola et al, 2015) methane seeps, the occurrence of authigenic siderite at seepage sites is less documented (Fritz et al, 1971;Curtis et al, 1972;Mozley and Wersin, 1992;Rongemaille et al, 2011). Siderite nodules have been reported in modern settings associated with methane seepage (Niger delta; Rongemaille et al, 2011) or methane hydrate decomposition (Black Outer Ridge; Matsumoto, 1989), and with highly ferruginous, low-sulfate, anoxic lake waters (e.g., Wittkop et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Authigenic minerals from the Paola Ridge (southern Tyrrhenian Sea): Evidences of episodic methane seepage

Franchi

Rovere

Gamberi

et al. 2017

Marine and Petroleum Geology

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a b s t r a c tPaola Ridge, along the NW Calabrian margin (southern Tyrrhenian Sea), is one of the few reported deep sea sites of precipitation of authigenic carbonates in the Tyrrhenian Sea. Here, the changing composition of the seeping fluids and the dynamic nature of the seepage induced the precipitation of pyrite, siderite and other carbonate phases. The occurrence of this array of authigenic precipitates is thought to be related to fluctuation of the sulfate-methane transition zone (SMTZ).Concretions of authigenic minerals formed in the near sub-bottom sediments of the Paola Ridge were investigated for their geochemical and isotopic composition. These concretions were collected in an area characterized by the presence of two alleged mud volcanoes and three mud diapirs. The mud diapirs are dotted by pockmarks and dissected by normal faults, and are known for having been a site of fluid seepage for at least the past 40 kyrs. Present-day venting activity occurs alongside the two alleged mud volcanoes and is dominated by CO 2 -rich discharging fluids. This discover led us to question the hypothesis of the mud volcanoes and investigate the origin of the fluids in each different domed structure of the study area.In this study, we used stable isotopes (carbon and oxygen) of carbonates coupled with rare earth element (REE) composition of different carbonate and non-carbonate phases for tracing fluid composition and early diagenesis of authigenic precipitates. The analyses on authigenic precipitates were coupled with chemical investigation of venting gas and sea-water.Authigenic calcite/aragonite concretions, from surficial sediments on diapiric structures, have depleted values. The siderite REE pattern shows consistent LREE (light REE) fractionation, MREE (medium REE) enrichment and positive Gd and La anomalies. As shown by the REE distribution, the 13 C-depleted composition and their association with chemosymbiotic fauna, calcite/aragonite precipitated at time of moderate to high methane flux close to the seafloor, under the influence of bottom seawater. Authigenic siderite, on the other hand, formed in the subseafloor, during periods of lower gas discharges under prolonged anoxic conditions within sediments in equilibrium with 13 C-rich dissolved inorganic carbon (DIC) and 18 O-rich water, likely related to methanogenesis and intermittent venting of deep-sourced CO 2 .

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Bivalve shell horizons in seafloor pockmarks of the last glacial‐interglacial transition: a thousand years of methane emissions in the Arctic Ocean

Ambrose

Panieri

Schneider

et al. 2015

Geochem Geophys Geosyst

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We studied discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (∼1200 m water depth) and western Svalbard (79°00′ N, 06°55′ W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20–30 cm thick and centered at 250–400 cm deep in the cores. The carbon isotope composition of inorganic (δ13C from −13.02‰ to +2.36‰) and organic (δ13C from −29.28‰ to −21.33‰) shell material and a two‐end member mixing model indicate that these taxa derived between 8% and 43% of their nutrition from chemosynthetic bacteria. In addition, negative δ13C values for planktonic foraminifera (−6.7‰ to −3.1‰), concretions identified as methane‐derived authigenic carbonates, and pyrite‐encrusted fossil worm tubes at the shell horizons indicate a sustained paleo‐methane seep environment. Combining sedimentation rates with 14C ages for bivalve material from the shell horizons, we estimate the horizons persisted for about 1000 years between approximately 17,707 and 16,680 years B.P. (corrected). The seepage event over a 1000 year time interval was most likely associated with regional stress‐related faulting and the subsequent release of overpressurized fluids.

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Methane-derived carbonates and authigenic pyrite from the northwestern Black Sea

Cited by 426 publications

References 70 publications

Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

Anomalous sea-floor backscatter patterns in methane venting areas, Dnepr paleo-delta, NW Black Sea

Authigenic minerals from the Paola Ridge (southern Tyrrhenian Sea): Evidences of episodic methane seepage

Bivalve shell horizons in seafloor pockmarks of the last glacial‐interglacial transition: a thousand years of methane emissions in the Arctic Ocean

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