Identification of primary Ce-anomaly signatures in fossil biogenic apatite: implication for the Cambrian oceanic anoxia and phosphogenesis

Morad, S.; Felitsyn, S. B.

doi:10.1016/s0037-0738(01)00093-8

Cited by 95 publications

(38 citation statements)

References 15 publications

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“…The trend is opposite to that of typical hydrothermal sedimentary rocks [38,39], but similar to exhalative rocks described by Zheng et al [16]. We speculate that this is caused by a low temperature (below 100°C) due to a mixing of lake water and hot hydrothermal fluid, which is much cooler than modern mid-ocean ridge hydrotermal fluid with a temperature of several hundred degrees celsius [40]. Last, the Eu and Ce anomaly patterns of doloarenites are somewhat similar to those of Tiaohu basalts (Figure 4, Table 3).…”

Section: Ree Resultssupporting

confidence: 61%

Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section, Santanghu area, Xinjiang, NW China

Liu

Jiao

et al. 2012

Sci. China Earth Sci.

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The Permian Lucaogou Formation is an important hydrocarbon source rock in the Junggar, Turpan, and Santanghu basins in Xinjiang, NW China. For the first time, dolostones associated with mantle-originated exhalative hydrothermal fluid flows are discovered in Yuejingou section in the Santanghu Basin area. They include dolomicrite, doloarenite, and a small amount of dolorudite, and are finely (0.05-0.15 cm thick) interlaminated with lime micrite and dolomicritic analcime laminites. Alkali feldspar and analcime grains are common in doloarenite and are interpreted as having been derived from analcime phonolites and peralkaline magmatic rocks. These magmatic fragments were brought up from subsurface by hydrothermal fluid flow and had experienced exhalative brecciation, transport, and deposition on the lake floor. The matrix consists dominantly of dolomite and ankerite smaller than 0.01 mm. The dolostones can be subdivided into four types on the basis of mineral composition and content. The detrital analcime and alkaline feldspar grains and tuff lithics are interpreted as intraclasts, which were deposited in an under-filled starved lake basin. The  18 O PDB values of dolostones are 5‰ to 21.1‰, and 11.9‰ on average; the 87 Sr/ 86 Sr ratios of dolostones are 0.70457 to 0.706194, and 0.705005 on average. These values, in combination with evidence of multiepisodes of peralkaline extrusion, suggest a mantle origin of the hydrothermal fluids, which may have promoted primary dolomite formation. The fluid from the upper mantle caused serpentinization of ultramafic rocks that intruded into the lower crust to obtain Mg 2+ and Fe 2+ , and injected the ions into the lake water as the Mg and Fe sources for dolomite and ankerite. Hydrothermal fluids associated with peralkaline magmatic rocks also provided Ca 2+ , Mg 2+ , Fe 2+ , and CO 3 2 . Explosive breccias formed and dolostones were convoluted near the vent of hydrothermal fluid exhalation, whereas laminated dolostones formed farther away from the vent. The dolostones are primary dolomite deposition in an intracontinental rift basin and associated with mantle-originated hydrothermal fluids. They provide an insight into the origin of dolomite formation in the geologic history and clues to understand the sedimentary environments and tectonic conditions in northern Xinjiang during the late Paleozoic. primary dolostone, mantle-originated hydrothermal exhalative deposits, intracontinental rift, Permian, Santanghu Area Citation: Liu Y Q, Jiao X, Li H, et al. Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section,

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Section: Ree Resultssupporting

confidence: 61%

Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section, Santanghu area, Xinjiang, NW China

Liu

Jiao

et al. 2012

Sci. China Earth Sci.

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“…In recent years, much attention has also been paid to the potential application of Ce anomaly as a paleooceanographic indicator of widespread marine anoxia, as well as a redox proxy in paleosols (Wright et al, 1987;MacLeod and Irving, 1996;Gallet et al, 1996;Holser, 1997;Morad and Felitsyn, 2001;Picard et al, 2002). However, many oxidizing waters do not exhibit negative Ce anomalies.…”

Section: Introductionmentioning

confidence: 99%

Adsorption of REE(III)-humate complexes onto MnO2: Experimental evidence for cerium anomaly and lanthanide tetrad effect suppression

Davranche¹,

Pourret²,

Gruau³

et al. 2005

Geochimica et Cosmochimica Acta

176

107

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Experiments were conducted to evaluate the impact of organic complexation on the development of Ce anomalies and the lanthanide tetrad effect during the adsorption of rare-earth elements (REE) onto MnO 2 . Two types of aqueous solutions-NaCl and NaNO 3 -were tested at pH 5 and 7.5. Time-series experiments indicate that a steady-state is reached within less than 10 h when REE occur as free inorganic species, whereas steady state is not reached before 10 d when REE occur as REE-humate complexes. The distribution coefficients (K d REE ) between suspended MnO 2 and solution show no or only very weak positive Ce anomaly or lanthanide tetrad effect when REE occur as humate complexes, unlike the results obtained in experiments with REE occurring as free inorganic species. Monitoring of dissolved organic carbon (DOC) concentrations show that log K d REE organic /K d DOC ratios are close to 1.0, implying that the REE and humate remain bound to each other upon adsorption. Most likely, the Ce anomaly reduction/suppression in the organic experiments arises from a combination of two processes: (i) inability of MnO 2 to oxidize Ce(III) because of shielding of MnO 2 surfaces by humate molecules and (ii) Ce(IV) cannot be preferentially removed from solution due to quantitative complexation of the REE by organic matter. We suggest that the lack of lanthanide tetrad effect arises because the adsorption of REE-humate complexes onto MnO 2 occurs dominantly via the humate side of the complexes (anionic adsorption), thereby preventing expression of the differences in Racah parameters for 4f electron repulsion between REE and the oxide surface. The results presented here explain why, despite the development of strongly oxidizing conditions and the presence of MnO 2 in the aquifer, no (or insignificant) negative Ce anomalies are observed in organic-rich waters. The present study demonstrates experimentally that the Ce anomaly cannot be used as a reliable proxy of redox conditions in organic-rich waters or in precipitates formed at equilibrium with organic-rich waters.

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“…Ce anomalies More frequently than europium anomalies, the cerium anomaly (Ce/Ce*) N has been used to address redox states in phosphorites during their diagenesis (e.g., Elderfield and Pagett, 1986;Wright et al, 1987;Morad and Felitsyn, 2001;Girard and Lécuyer, 2002;Kemp and Trueman, 2003;Jiang et al, 2007;Khan et al, 2012).…”

Section: Eu and Ce Anomaliesmentioning

confidence: 99%

Preservation of successive diagenetic stages in Middle Triassic bonebeds: Evidence from in situ trace element and strontium isotope analysis of vertebrate fossils

et al. 2015

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Identification of primary Ce-anomaly signatures in fossil biogenic apatite: implication for the Cambrian oceanic anoxia and phosphogenesis

Cited by 95 publications

References 15 publications

Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section, Santanghu area, Xinjiang, NW China

Primary dolostone formation related to mantle-originated exhalative hydrothermal activities, Permian Yuejingou section, Santanghu area, Xinjiang, NW China

Adsorption of REE(III)-humate complexes onto MnO2: Experimental evidence for cerium anomaly and lanthanide tetrad effect suppression

Preservation of successive diagenetic stages in Middle Triassic bonebeds: Evidence from in situ trace element and strontium isotope analysis of vertebrate fossils

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