Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments

Thiagarajan, Nivedita; Crémière, Antoine; Blättler, Clara L.; Lepland, Aivo; Kirsimäe, Kalle; Higgins, John A.; Brunstad, Harald; Eiler, John M.

doi:10.1016/j.gca.2020.03.015

Cited by 29 publications

(23 citation statements)

References 73 publications

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“…The study of authigenic carbonates in the cold seep area mainly focus on the determination of the origin, formation time of authigenic carbonates, and the source of seepage fluid by isotope method [11][12][13]. Some papers have discussed the different formation model of authigenic carbonates in the methane-bearing cold seep by studying sediment cores [14,15].…”

Section: Introductionmentioning

confidence: 99%

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Wei

Shang

et al. 2021

JMSE

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Authigenic carbonates are widely distributed in marine sediments, microbes, and anaerobic oxidation of methane (AOM) play a key role in their formation. The authigenic carbonates in marine sediments have been affected by weathering and diagenesis for a long time, it is difficult to understand their formation process by analyzing the samples collected in situ. A pore water environment with 10 °C, 6 MPa in the marine sediments was built in a bioreactor to study the stages and characteristics of authigenic carbonates formation induced by microbes. In experiments, FeCO3 is formed preferentially, and then FeCO3-MgCO3 complete isomorphous series and a small part of CaCO3 isomorphous mixture are formed. According to this, it is proposed that the formation of authigenic carbonates performed by AOM and related microbes needs to undergo three stages: the rise of alkalinity, the preferential formation of a carbonate mineral, and the formation of carbonate isomorphous series. This work provides experimental experience and reference basis for further understanding the formation mechanism of authigenic carbonates in marine sediments.

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Section: Introductionmentioning

confidence: 99%

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Wei

Shang

et al. 2021

JMSE

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“…Geophysical Research Letters disequilibrium can cause larger variance in replicate measurements and significant deviation in T(Δ 47 ) from precipitation temperatures (Guo, 2020). Importantly, a carbonate system out of isotopic equilibrium with respect to one set of equilibria may also yield disequilibrium behavior in other isotope systems, for example, Ca isotopes, and inform other geochemical data impacted by kinetics (e.g., Thiagarajan et al, 2020).…”

Section: 1029/2020gl088804mentioning

confidence: 99%

“…We attributed the unusually warm T(Δ 47 ) values and sample heterogeneity to variably expressed KIEs driven by fast tufa carbonate formation. Although magnitude of KIEs is independent, both Δ 47 and Ca isotopes are susceptible to precipitation rate-driven KIEs (Thiagarajan et al, 2020), and thus, we hypothesized that some amount of the tufa δ 44/40 Ca variability captured kinetics in ways that masked the expected patterns of Rayleigh distillation.…”

Section: Field Observations To Identify Closed-basin Chemistry Without Geochemical Toolsmentioning

confidence: 99%

P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels

Ingalls

Blättler

Higgins

et al. 2020

Geophysical Research Letters

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Understanding mechanisms, rates, and drivers of past carbonate formation provides insight into the chemical evolution of Earth's oceans and atmosphere. We paired geological observations with elemental and isotope geochemistry to test potential proxies for calcium-to-alkalinity ratios (Ca:ALK). Across diverse carbonate facies from Pleistocene closed-basin lakes in Owens Valley, CA, we observed less δ 44/40 Ca variation than theoretically predicted (>0.75‰) for the very low Ca:ALK in these systems. Carbonate clumped isotope disequilibria implied rapid carbonate growth-kinetic isotope effects, combined with the diverse carbonate minerals present, complicated the interpretation of δ 44/40 Ca as a paleoalkalinity proxy. In contrast, we observed that the high phosphate concentrations are recorded by shoreline and lake bottom carbonates formed in 11 Pleistocene lakes at orders of magnitude greater concentrations than in marine carbonates. Because the maximum phosphate content of water depends on Ca:ALK, we propose that carbonate P/Ca can inform phosphate levels and thereby Ca:ALK of aqueous environments in the carbonate record. Plain Language Summary Carbonate minerals record information about the local environments in which they form, for example, along the margins of a lake or on the seabed, as well as the aqueous and atmospheric chemistry at the time of mineralization (e.g., pCO 2 and pH). This information is recorded in both the chemical signatures and textures carbonate rocks acquire during precipitation. Formation of calcium carbonate requires both a source of calcium (Ca 2+) and carbonate (CO 3 2− or carbonate alkalinity [ALK]). The ratio of calcium to alkalinity (Ca:ALK) in lake or ocean water influences the rate of carbonate formation, the textures that carbonate will develop, and the chemical signatures recorded by the carbonate mineral. In this study, we tested several approaches to identify very low Ca:ALK chemistry in modern and ancient lakes. We found that water with extremely low levels of calcium and high levels of alkalinity forms carbonates with a characteristic "tufa" texture in stratigraphic positions tied to riverine and groundwater sources of Ca 2+. Moreover, the phosphate concentrations in these rocks were orders of magnitude higher than carbonates that precipitate under the high Ca:ALK conditions of modern oceans. Together, the results illustrated that identification of carbonate tufa textures in the rock record and phosphate measurements of carbonate rocks can be used to study the ancient environments and mechanisms by which carbonate rocks formed.

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“…As a result of AOM, an abundance of dissolved inorganic carbon arises and the alkalinity of pore water increases. The presence of seawater cations (Ca 2+ , Mg 2+ ) and elevated carbonate alkalinity promote the precipitation of authigenic carbonates [7,19], which show a wide range of mineralogical compositions. The occurrence of Mg-calcite and aragonite in cold seep marine environments has been reported by various authors [1,4,20].…”

Section: Introductionmentioning

confidence: 99%

“…Authigenic carbonates from cold seeps are unique archives for studying environmental conditions, including biogeochemical processes associated with the migration of methane-rich fluid through the sediment column [19,23,24]. The isotopic compositions of carbon and oxygen in authigenic carbonates are key to solving questions regarding conditions under which carbonates form [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

The Formation of Authigenic Carbonates at a Methane Seep Site in the Northern Part of the Laptev Sea

et al. 2020

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Authigenic carbonates from cold seeps are unique archives for studying environmental conditions, including biogeochemical processes associated with methane-rich fluid migration through the sediment column. The aim of this research was to study major oxide, mineralogical, and stable isotopic compositions of cold-seep authigenic carbonates collected in the northern part of the Laptev Sea. These carbonates are represented by Mg-calcite with an Mg content of 2% to 8%. The δ13C values range from −27.5‰ to −28.2‰ Vienna Peedee belemnite (VPDB) and indicate that carbonates formed due to anaerobic oxidation of methane, most likely thermogenic in origin. The authigenic pyrite in Mg-calcite is evidence of sulfate reduction during carbonate precipitation. The δ18O values of carbonates vary from 3.5‰ to 3.8‰ VPDB. The calculated δ18Ofluid values show that pore water temperature for precipitated Mg-calcite was comparable to bottom seawater temperature. The presence of authigenic carbonate in the upper horizons of sediments suggests that the sulfate–methane transition zone is shallowly below the sediment–water interface.

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Stable and clumped isotope characterization of authigenic carbonates in methane cold seep environments

Cited by 29 publications

References 73 publications

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

Laboratory Experimental Study on the Formation of Authigenic Carbonates Induced by Microbes in Marine Sediments

P/Ca in Carbonates as a Proxy for Alkalinity and Phosphate Levels

The Formation of Authigenic Carbonates at a Methane Seep Site in the Northern Part of the Laptev Sea

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