Seep-carbonate lamination controlled by cyclic particle flux

Himmler, Tobias; Bayon, Germain; Wangner, David J.; Enzmann, Frieder; Peckmann, Jörn; Bohrmann, Gerhard

doi:10.1038/srep37439

Cited by 20 publications

(6 citation statements)

References 35 publications

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“…(MDAC 5: age8 → age7, MDAC 2: age4 → age 3). Our estimated carbonate precipitation rate of 5.3 mm/ka from one of the aragonite linings appears slow compared to other studies that find rates between 4 and 50 mm/ka in a crust from the Nile deep-sea fan (Bayon et al 2009), around 10-20 mm/ka in the Barents Sea (Crémière et al 2016a), 48 mm/ka in a theoretical study of carbonate precipitation (Luff et al 2004), and approximately 470 mm/ka for a carbonate build-up in the northern Arabian Sea (Himmler et al 2016). Fig.…”

Section: Timing Of Mdac Formation and Potential Driving Processescontrasting

confidence: 56%

U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway

et al. 2017

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We investigated methane-derived authigenic carbonate (MDAC) crusts and nodules from a cold seep site on the northern Norwegian continental shelf in ca. 220 m water depth to determine the timing and mode of their formation. Gas bubbling observed during remotely operated vehicle (ROV)-assisted sampling of MDAC crusts revealed ongoing seep activity. Authigenic carbonates were present as crusts on the seafloor and as centimetre-size carbonate-cemented nodules at several intervals within an adjacent sediment core. Aragonite-dominated mineralogy of the MDAC crusts suggests formation close to the seafloor at higher rates of sulphate-dependent anaerobic oxidation of methane (AOM). In contrast, dolomite-cemented nodules are consistent with the formation at the sulphate-methane-transition zone deeper within the sediment at lower rates of AOM. The δ 13 C-carbonate values of bulk rock and of micro-drilled aragonite samples vary between − 22.2‰ and − 34.6‰ (VPDB). We interpret the carbon in aragonite to be mainly derived from the anaerobic oxidation of thermogenic methane, with a minor contribution from seawater dissolved inorganic carbon (DIC). AOM activity is supported by high concentrations of AOM-related biomarkers of archaea (archaeol and 2-sn-hydroxyarchaeol) and sulphate-reducing bacteria (iso and anteiso-C 15:0 fatty acids) in the crusts. The dolomite nodules exhibit higher δ 13 C-carbonate values (− 12‰ VPDB) suggesting a smaller amount of methane-derived carbon, presumably due to the contribution of DIC migrating from depth, and lower AOM rates. The latter is supported by orders of magnitude lower concentrations of archaeol and sn-2-hydroxyarchaeol in the sediment interval containing the largest dolomite nodules. δ 18 O values of pure aragonite samples and dolomite nodules indicate the precipitation of carbonate close to isotopic equilibrium with seawater and no influence of gas hydrate-derived water. U-Th dating of two MDAC crusts shows that they formed between 1.61 ± 0.02 and 4.39 ± 1.63 ka BP and between 2.65 ± 0.02 and 4.32 ± 0.08 ka BP. We infer both a spatial and temporal change in methane flux and related MDAC formation at this seep site. These changes might be caused by regional seismic events that can affect pore pressure or re-activation of migration pathways thus facilitating fluid flow from deep sources towards the seabed.

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Section: Timing Of Mdac Formation and Potential Driving Processescontrasting

confidence: 56%

U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway

et al. 2017

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“…The Black Sea features large columnar carbonate deposits that project into anoxic bottom waters, and studies have shown that such conditions are favourable for anaerobic methane‐metabolizing microbial communities (Michaelis et al ., ; Treude et al ., ). Ephemeral anoxic conditions due to enhanced primary production in surface waters have also been inferred for carbonate formation in bottom waters of the Mediterranean Sea (Bayon et al ., ), similar to the situation in the oxygen minimum zone (OMZ) on the Makran continental shelf, where seep deposits project into oxygen deprived bottom waters (Himmler et al ., , , ). Moreover, Teichert et al .…”

Section: Discussionmentioning

confidence: 99%

Oil seepage and carbonate formation: A case study from the southern Gulf of Mexico

et al. 2019

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Oil seeps from the southern Gulf of Mexico can be regarded as natural laboratories where the effect of crude oil seepage on chemosynthesis‐based communities and carbonate precipitation can be studied. During R/V Meteor cruise 114 the seep sites UNAM (Universidad Nacional Autónoma de México) Ridge, Mictlan Knoll and Tsanyao Yang Knoll (Bay of Campeche, southern Gulf of Mexico) were investigated and sampled for authigenic carbonate deposits containing large amounts of liquid oil and solid asphalt. The δ13C values of individual carbonate phases including: (i) microcrystalline matrix aragonite and calcite; (ii) grey, cryptocrystalline to microcrystalline aragonite; and (iii) clear, fibrous aragonite cement, are between −30‰ and −20‰, agreeing with oil as the primary carbon source. Raman spectra reveal that residual heavy oils from all sites are immature and most likely originate from the same reservoir. Geochemical batch modelling using the software code PHREEQC demonstrates how sulphate‐driven oxidation of oil‐derived low‐molecular to high‐molecular weight hydrocarbons affects carbonate saturation state, and shows that the oxidation state of carbon in hydrocarbon compounds and oxidation rates of hydrocarbons control carbonate saturation and precipitation at oil seeps. Phase‐specific trace and rare earth element contents of microcrystalline aragonite and calcite, grey cryptocrystalline aragonite and clear aragonite were determined, revealing enrichment in light rare earth elements for grey aragonite. By comparing trace element patterns of carbonates with those of associated oils, it becomes apparent that liquid hydrocarbons constitute an additional source of trace metals to sedimentary pore waters. This work not only demonstrates that the microbial degradation of oil at seeps may result in the precipitation of carbonate minerals, it also elucidates that trace metal inventories of seep carbonates archive diagnostic elemental patterns, which can be assigned to the presence of heavy hydrocarbons in interstitial pore waters.

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“…gas hydrate is estimated to cover an area of about 55 km 2 today . Samples from water depths between 200 and 1,000 m represent sites with a possible link between hydrostatic pressure and hydrate dissociation (Çağatay et al, 2018;Crémière et al, 2013;Han et al, 2014;Himmler et al, 2016;Liebetrau et al, 2010Liebetrau et al, , 2014Mazzini et al, 2017;Prouty et al, 2016;Ruffine et al, 2013;Teichert et al, 2003;Tong et al, 2013;Yang, Chu, et al, 2018). 3. the average gas hydrate saturation estimated from pore water freshening analysis ranges from 45% to 55% of the total pore space we use 50% for calculation); 4.…”

Section: Estimating Past Methane Flux Caused By Gas Hydrate Dissociationmentioning

confidence: 99%

“…Samples from water depths greater than 1,000 m (Aharon et al, 1997;Bayon, Loncke, et al, 2009;Bayon et al, 2013Bayon et al, , 2015Çağatay et al, 2018;Crémière et al, 2013;Feng et al, 2010;Himmler et al, 2015Himmler et al, , 2019Kutterolf et al, 2008;Lalou et al, 1992;Liebetrau et al, 2010Liebetrau et al, , 2014Mazumdar et al, 2009;Prouty et al, 2016;Watanabe et al, 2008) represent sites with a weak link between hydrostatic pressure and hydrate dissociation, whereas samples from water depths less than 200 m represent sites were hydrate dissociation was not involved (Aharon et al, 1997;Crémière, Lepland, Chand, Sahy, Kirsimäe, et al, 2016;Feng et al, 2010). Samples from water depths between 200 and 1,000 m represent sites with a possible link between hydrostatic pressure and hydrate dissociation (Çağatay et al, 2018;Crémière et al, 2013;Han et al, 2014;Himmler et al, 2016;Liebetrau et al, 2010Liebetrau et al, , 2014Mazzini et al, 2017;Prouty et al, 2016;Ruffine et al, 2013;Teichert et al, 2003;Tong et al, 2013;Yang, Chu, et al, 2018). Note that the Norwegian margin was glaciated during the last Ice Age.…”

Section: Estimating Past Methane Flux Caused By Gas Hydrate Dissociationmentioning

confidence: 99%

Gas Hydrate Dissociation During Sea‐Level Highstand Inferred From U/Th Dating of Seep Carbonate From the South China Sea

Fang

Wang

et al. 2019

Geophysical Research Letters

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Gas hydrates represent a huge reservoir of methane in marine sediments, prone to dissociation in response to environmental changes. There is consensus that past events of gas hydrate dissociation in the marine environment mainly occurred during periods of low sea level. Here, we report geochemical data for 2-m-thick layers of seep carbonate collected from a hydrate-bearing drill core from~800-m water depth in the northern South China Sea. The aragonite-rich carbonates reveal positive δ 18 O values, confirming a genetic link with gas hydrate dissociation. Uranium-thorium dating of seep carbonates indicates that gas hydrates at the study site dissociated between 133,300 and 112,700 years BP, hence coinciding with the Last Interglacial (MIS 5e) sea-level highstand. We put forward the concept that a climate-driven increase in temperature was responsible for a period of pronounced gas hydrate dissociation.Plain Language Summary The gas hydrate reservoir is a dynamically changing system extremely susceptible to variations of seafloor temperature and pressure. Therefore, gas hydrate dissociation and subsequent methane seepage frequently occur during times of global climate change, especially during sea-level lowstands with reduced seabed pressure. However, this conclusion was mainly based on dating of seep carbonates sampled from the seabed. As a consequence, one cannot exclude that previous results have been compromised by a sampling bias since seafloor samples are easier to collect. Authigenic seep carbonates from drill cores represent a continuous record of gas hydrate dynamics. Our uranium-thorium dating of seep carbonate from drill cores provides a unique example of the effects of temperature and pressure on the stability of the hydrate system in the Dongsha area, northern South China Sea (SCS), during the last interglacial stage (MIS 5e, about 130,000 years BP). Representing the most similar and most contemporary analog to the current interglacial, the study of a methane release event in the SCS during MIS 5e will shed light on the expected trend of methane release events in the future, while providing insight into the response of low-latitude oceans to climate change.Supporting Information:• Data Set S1

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Seep-carbonate lamination controlled by cyclic particle flux

Cited by 20 publications

References 35 publications

U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway

U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway

Oil seepage and carbonate formation: A case study from the southern Gulf of Mexico

Gas Hydrate Dissociation During Sea‐Level Highstand Inferred From U/Th Dating of Seep Carbonate From the South China Sea

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