δ44/40Ca variability in shallow water carbonates and the impact of submarine groundwater discharge on Ca-cycling in marine environments

Holmden, Chris; Papanastassiou, D. A.; Blanchon, Paul; Evans, Siân

doi:10.1016/j.gca.2011.12.031

Cited by 80 publications

(37 citation statements)

References 72 publications

(121 reference statements)

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“…Subsequently, similar  44 Ca data were recently reported for different genera and varying environmental conditions (Pretet et al, 2013;Holmden et al, 2012). The overall mean value of  44 Ca was comparable within error: 0.81 ± 0.05 ‰ by Böhm et al (2006), yielding about + 0.5 ‰ offset from inorganic and sclerosponge aragonite, which was interpreted as the result of biological Ca isotope fractionation during Ca transmembrane transport (Böhm et al, 2006), similar to observations of biological fractionation on coccolithophores .…”

Section: Introductionsupporting

confidence: 84%

Controlling factors of Ca isotope fractionation in scleractinian corals evaluated by temperature, pH and light controlled culture experiments

Inoue

Gussone

Koga

et al. 2015

Geochimica et Cosmochimica Acta

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Section: Introductionsupporting

confidence: 84%

Controlling factors of Ca isotope fractionation in scleractinian corals evaluated by temperature, pH and light controlled culture experiments

Inoue

Gussone

Koga

et al. 2015

Geochimica et Cosmochimica Acta

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“…Nevertheless, there is no evidence for an adjacent river carrying lighter Li isotopes in the suspended material from basaltic and/or continental terrain (Pogge von Strandmann et al, 2010). Local effects like upwelling/downwelling and/or submarine groundwater discharge, which have been proposed as influences on Ca isotopes (Holmden et al, 2012), might have affected the local Li-isotope record. However, modern oceans are considered to be isotopically homogenous with respect to lithium (Chan & Edmond, 1988;Stoffyn-Egli & MacKenzie, 1984).…”

Section: Smaller Variations In Li-isotope Values During the Event Likmentioning

confidence: 99%

Lithium-isotope evidence for enhanced silicate weathering during OAE 1a (Early Aptian Selli event)

Lechler

Strandmann

Jenkyns

et al. 2015

Earth and Planetary Science Letters

104

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An abrupt rise in temperature, forced by a massive input of CO 2 into the atmosphere, is commonly invoked as the main trigger for Oceanic Anoxic Events (OAEs). Global warming initiated a cascade of palaeoenvironmental perturbations starting with increased continental weathering and an accelerated hydrological cycle that delivered higher loads of nutrients to coastal areas, stimulating biological productivity.The end-result was widespread anoxia and deposition of black shales: the hallmarks of OAEs. In order to assess the role of weathering as both an OAE initiator and terminator (via CO 2 sequestration) during the Early Aptian OAE 1a (Selli Event, ~120 Ma) the isotopic ratio of lithium isotopes was analysed in three sections of shallowmarine carbonates from the Pacific and Tethyan realm and one basinal pelagic section from the Tethyan domain. Because the isotopic composition of lithium in seawater is largely controlled by continental silicate weathering and high-and lowtemperature alteration of basaltic material, a shift to lighter  7 Li values is expected to characterize OAEs. The studied sections illustrate this phenomenon:  7 Li values decrease to a minimum coincident with the negative carbon-isotope excursion that effectively records the onset of OAE 1a. A second negative  7 Li excursion occurs coeval with the minimum in strontium isotopes after the event. The striking similarity to the strontium-isotope record argues for a common driver. The formation and destruction (weathering) of an oceanic LIP could account for the parallel trend in both isotope systems. The double-spike in lithium isotopes is probably related to a change in weathering congruencies. Such a chemostratigraphy is consistent with the hypothesis that an increase in silicate weathering, in conjunction with organic-carbon burial, led to drawdown of atmospheric CO 2 during the early Aptian OAE 1a.

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“…Finally, the timing of dolomitization and its fluid source remain challenging to infer, but 416 numerous models indicate that both seawater and external fluids can be involved in this process 417 (e.g., Land, 1985 (Komar and Zeebe, 2016). Figure 7D; Holmden et al, 2012b). (Figure 4), we 498 eliminate a secular change in seawater Ca and Sr ( Figure 7A) as the principal factor controlling 499 the stratigraphic trends in these carbonate rocks.…”

mentioning

confidence: 99%

The influence of seawater carbonate chemistry, mineralogy, and diagenesis on calcium isotope variations in Lower-Middle Triassic carbonate rocks

et al. 2017

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δ44/40Ca variability in shallow water carbonates and the impact of submarine groundwater discharge on Ca-cycling in marine environments

Cited by 80 publications

References 72 publications

Controlling factors of Ca isotope fractionation in scleractinian corals evaluated by temperature, pH and light controlled culture experiments

Controlling factors of Ca isotope fractionation in scleractinian corals evaluated by temperature, pH and light controlled culture experiments

Lithium-isotope evidence for enhanced silicate weathering during OAE 1a (Early Aptian Selli event)

The influence of seawater carbonate chemistry, mineralogy, and diagenesis on calcium isotope variations in Lower-Middle Triassic carbonate rocks

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