Isotopic evidence for source of diagenetic carbonates formed during burial of organic-rich sediments

Irwin, Hilary; Curtis, C. D.; Coleman, Max

doi:10.1038/269209a0

Cited by 1,237 publications

(659 citation statements)

References 18 publications

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“…ð1:7Þ (Irwin et al 1977). In Phanerozoic strata, which have formed in the presence of relatively abundant O 2 and SO 2K 4 , this phenomenon is restricted to concretions or other zones, in which supplies of sedimentary organic matter have been large enough that methanogenesis has eventually become prominent.…”

Section: The Structure Of the Carbon Cyclementioning

confidence: 99%

The carbon cycle and associated redox processes through time

Hayes

Waldbauer

2006

Phil. Trans. R. Soc. B

428

308

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Earth's biogeochemical cycle of carbon delivers both limestones and organic materials to the crust. In numerous, biologically catalysed redox reactions, hydrogen, sulphur, iron, and oxygen serve prominently as electron donors and acceptors. The progress of these reactions can be reconstructed from records of variations in the abundance of 13 C in sedimentary carbonate minerals and organic materials. Because the crust is always receiving new CO 2 from the mantle and a portion of it is being reduced by photoautotrophs, the carbon cycle has continuously released oxidizing power. Most of it is represented by Fe 3C that has accumulated in the crust or been returned to the mantle via subduction. Less than 3% of the estimated, integrated production of oxidizing power since 3.8 Gyr ago is represented by O 2 in the atmosphere and dissolved in seawater. The balance is represented by sulphate. The accumulation of oxidizing power can be estimated from budgets summarizing inputs of mantle carbon and rates of organic-carbon burial, but levels of O 2 are only weakly and indirectly coupled to those phenomena and thus to carbon-isotopic records. Elevated abundances of 13 C in carbonate minerals ca 2.3 Gyr old, in particular, are here interpreted as indicating the importance of methanogenic bacteria in sediments rather than increased burial of organic carbon.

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Section: The Structure Of the Carbon Cyclementioning

confidence: 99%

The carbon cycle and associated redox processes through time

Hayes

Waldbauer

2006

Phil. Trans. R. Soc. B

428

308

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“…7) were interpreted by Halverson et al (2004) as an indication of early, microbially mediated diagenesis (cf. Irwin et al, 1977). Whilst this is valid, the newly enlarged dataset (Fig.…”

Section: Descriptionmentioning

confidence: 99%

“…15) can be assumed to be a direct reflection of the changing pore fluid composition of these elements. Changing availability of Fe and Mn either reflects microbial reduction of progressively more refractory oxidized sources of these minerals (Irwin et al, 1977) or downward diffusion from overlying seawater with fluctuating Fe-Mn chemistry. The lack of δ 13 C variability in dolomites implies buffering by a pre-existing fine-grained carbonate phase.…”

Section: Geochemistry and Petrologymentioning

confidence: 99%

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

Fairchild

Bonnand²,

Davies

et al. 2016

Precambrian Research

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms At the base of E3, interstratification of cap carbonate with ice-rafted and redeposited glacial sediments occurs. Early diagenetic stabilization of carbonate mineralogy from a precursor, possibly ikaite, to calcite or dolomite is inferred. E3 is predominantly dolomitic silt-shale, with sub-millimetre lamination, lacking sand or current-related sedimentary structures. Thin fine laminae are partly pyritized and interpreted as microbial mats. Dolomite content is 25-50%, with δ 13 C values consistently around +4‰, a value attributed to buffering by dissolution of a precursor metastable carbonate phase. Local calcite cement associates with low δ 13 C values. The carbonates form silt-sized, chemically zoned rhombic crystals from an environment with dynamically changing Fe and Mn. Three-dimensional reconstructions of cm-scale disturbance structures indicate that they represent horizontally directed sock-like folds, developed by release of overpressure into thin surficial sediment overlying an early-cemented layer.A shoaling upwards unit near the top of E3 displays calcium sulphate pseudomorphs in dolomite in the north, but storm-dominated limestones in the south, both being overlain by peritidal oolitic dolomites, exposed under the succeeding Wilsonbreen glacial deposits. There is no Trezona δ 13 C anomaly, possibly implying top-truncation of the succession.Regular 0.5 m-scale sedimentary rhythms, reflecting subtle variations in sediment texture or composition occur throughout E3 and are interpreted as allocyclic. They are thought to be mainly primary in origin, locally modified slightly during early diagenetic cementation. Rhythms are proposed to represent ca. 18 kyr precession cycles, implying 6-8 Myr deposition between glaciations.

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“…As discussed above, siderite concretions at Paola Ridge show evidences of precipitation within the fermentation zone (e.g., Irwin et al, 1977;Matsumoto, 1989;Wittkop et al, 2014). Authigenic siderite formed within the methanogenesis zone, where metabolic activity of microbial consortia triggers the precipitation of authigenic carbonates (e.g., Chafetz and Buczynski, 1992;Monty, 1995), may thus lack a consistent Ce anomaly as shown by Paola Ridge samples.…”

Section: Redox Conditions During Sedimentationmentioning

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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Isotopic evidence for source of diagenetic carbonates formed during burial of organic-rich sediments

Cited by 1,237 publications

References 18 publications

The carbon cycle and associated redox processes through time

The carbon cycle and associated redox processes through time

The Late Cryogenian Warm Interval, NE Svalbard: Chemostratigraphy and genesis

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

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