Controls of REY enrichment in the early Cambrian phosphorites

Zhang, Hongjie; Fan, Haifeng; Wen, Hao; Han, Tao; Zhou, Ting; Xia, Yujie

doi:10.1016/j.gca.2022.03.003

Cited by 26 publications

(24 citation statements)

References 114 publications

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“…The PAAS-normalized REY patterns of Zhijin phosphorites exhibit positive La anomalies, positive Gd anomalies, negative Ce anomalies (0.32-0.45), and HREE depletions (Figure 8). This and previous results suggest that both the negative Ce anomalies (0.32-0.52) and Y/Ho values (45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60) of Zhijin phosphorites represent seawater characteristics [31]. Meanwhile, the Sr-Nd isotopes of Zhijin phosphorites are consistent with those of Cambrian seawater [88].…”

Section: Effect Of Organic Matter On Rey Enrichmentsupporting

confidence: 81%

“…Previous studies revealed that redox stratification developed during the Ediacaran-Cambrian transition with oxic surface seawater and anoxic/euxinic deep seawater [20]. The whole-rock Fe isotopes (~0‰) from the MSC phosphorus deposit indicate that these phosphorites were deposited under an oxic seawater environment [52]. However, the whole-rock Fe isotopes (~0-0.45‰) of the Zhijin phosphorus deposit indicate a fluctuating oxic-suboxic seawater environment [52].…”

Section: Controls On δ 13 C Orgmentioning

confidence: 98%

“…The whole-rock Fe isotopes (~0‰) from the MSC phosphorus deposit indicate that these phosphorites were deposited under an oxic seawater environment [52]. However, the whole-rock Fe isotopes (~0-0.45‰) of the Zhijin phosphorus deposit indicate a fluctuating oxic-suboxic seawater environment [52]. The redox environment of Zhijin seawater recorded by Fe isotopes is consistent with the weakened hydrodynamic condition recorded by petrography during the Zhijin phosphorus rock series sedimentary (see Section 2.2.).…”

Section: Controls On δ 13 C Orgmentioning

confidence: 99%

“…The PAAS-normalized REY patterns of typical phosphorites (e.g., Meishucun phosphorites) during the early Cambrian Period exhibit obviously positive La and Gd anomalies, and negative Ce anomalies, as well as HREE depletion characteristics [51,52], which are thought to be influenced by diagenesis. Due to this influence, Ce anomalies exhibit a positive correlation with the ∑REY, and a negative correlation with Dy N /Sm N ratios [51].…”

Section: Diagenetic Evaluationmentioning

confidence: 99%

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Assessment of the Effect of Organic Matter on Rare Earth Elements and Yttrium Using the Zhijin Early Cambrian Phosphorite as an Example

Yang

Fan

et al. 2022

Minerals

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The geochemistry of rare earth elements and yttrium (REY) in phosphorite has been widely studied. However, the effect of organic matter on REY enrichment has not been well determined. We utilized paired inorganic (δ13Ccarb) and organic (δ13Ccarb) carbon isotopes, total organic carbon (TOC), and REY content (∑REY) of the Zhijin Motianchong (MTC) phosphorite and compared them with those of Meishucun (MSC) phosphorite to reveal the effect of organic matter on REY. The δ13Ccarb of the MTC area (≈0‰) is heavier than that of the MSC area (−5.23‰ to −1.13‰), whereas δ13Corg is lighter (−33.85‰ to −26.34‰) in MTC than in MSC (−32.95‰ to −25.50‰). Decoupled δ13Ccarb and δ13Corg in MTC indicate the contribution of chemoautotrophic organisms or methanotrophic bacteria. Compared to the MSC phosphorite, the MTC phosphorite has higher ∑REY and TOC, and these parameters have a positive relationship. MTC phosphorite has REY patterns resembling those of contemporary organic matter. Furthermore, dolomite cement has a higher ∑REY than dolomite in the phosphorus-bearing dolostone. Additionally, pyrites are located on the surface of fluorapatite in the Zhijin phosphorites. It is reasonable to suggest that the REY was released into the pore water owing to the anaerobic oxidation of organic matter at the interface between seawater and sediment, resulting in the REY enrichment of Zhijin phosphorites.

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Section: Effect Of Organic Matter On Rey Enrichmentsupporting

confidence: 81%

Section: Controls On δ 13 C Orgmentioning

confidence: 98%

Section: Controls On δ 13 C Orgmentioning

confidence: 99%

Section: Diagenetic Evaluationmentioning

confidence: 99%

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Assessment of the Effect of Organic Matter on Rare Earth Elements and Yttrium Using the Zhijin Early Cambrian Phosphorite as an Example

Yang

Fan

et al. 2022

Minerals

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“…However, many studies believe that the Ce anomalies in francolite may also involve REY fractionation during diagenetic uptake and relate to porewater REY chemistry, which cannot effectively constrain the redox environment [38][39][40] If the poor correlation between Ce/Ce � values and Y/Ho ratios in phosphorites indicates that this principle is also applicable to phosphorites [40]. There is a poor correlation between Ce/Ce � values and Y/Ho ratio (R 2 = 0.06, p>0.05) (Fig 9b), indicating that the Ce anomaly of Zhijin phosphorites may not only be affected by the REDOX state of seawater, but also may be caused by REY fractionation during diagenetic absorption.…”

Section: Sedimentary Environment Of Phosphoritesmentioning

confidence: 99%

Studies on geochemical characteristics and biomineralization of Cambrian phosphorites, Zhijin, Guizhou Province, China

Gao

Yang

et al. 2023

PLoS ONE

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Phosphate rocks, an important ore resource in Guizhou Province, China, are mainly hosted within the Sinian Doushantuo Formation and the Cambrian Meishucun Formation. In addition, the phosphate rocks of the Cambrian Meishucun Formation are rich in biological fossils. Although numerous studies investigating the genesis of phosphate deposits have been performed, the relationship between biological activity and the formation of phosphate deposits in the lower Cambrian Meishucun Formation has not been convincingly explained. This study focuses on the biological fossil assemblage, the characteristics of phosphorus, and the relationship between biological and phosphorus enrichment of the lower Cambrian phosphorites. The primary objectives of our study are to analyze the role of organisms in the formation of phosphorites, restore the phosphorus-formation environment of the Cambrian Meishucun Formation, and construct a sedimentary model of the phosphorites in the Meishucun Formation. The results indicate that there is a significant positive correlation between biological activity and the deposition of phosphorites, that is, the higher the degree of biological enrichment and differentiation, the stronger the deposition. The geochemical analysis of several profiles in the Zhijin phosphorite block shows that the phosphorite block was deposited in an oxygen-rich environment and was affected by a high-temperature hydrothermal fluid. Upwelling ocean currents supplied abundant phosphorus and other nutrients, which provided the conditions for small shells and algae to flourish. Biochemical activity was a crucial factor in the deposition of the phosphorite.

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Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

Xie

2023

Surface & Interface Analysis

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The rare earth elements (REEs)‐bearing phosphorite was a potential REE resource, which contained all REEs except polonium, among them lanthanide, cerium, neodymium, and yttrium were especially enriched. REEs mainly occurred in fluorapatite (Fap) and had a high positive correlation with phosphorus content. By adopting a new green environmental fatty acid collector GJBW and through one roughing and one refining reverse flotation process, all REEs were pre‐enriched. The flotation concentrate was further leached with citric acid (CA), and all REEs were further enriched. The results of X‐ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray photoelectron spectroscopy (XPS) showed that dolomite (Dolo) was removed and Fap was enriched in phosphorite, the selective enrichment of phosphorus and REEs was realized. Density functional theory (DFT) calculation revealed the mechanism of deep purification of REEs and phosphorus in phosphorite by CA at the micro‐scale. The results showed that the number and strength of bonding between CA and Dolo (104) surface were greater than that between CA and Fap (001) surface, and CA was more easily adsorbed on Dolo (104) surface. Under the same conditions, Dolo in phosphorite was more easily leached by CA, while Fap was further enriched. This process provided a theoretical basis for the comprehensive recovery of REEs and phosphorus from phosphorite.

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Controls of REY enrichment in the early Cambrian phosphorites

Cited by 26 publications

References 114 publications

Assessment of the Effect of Organic Matter on Rare Earth Elements and Yttrium Using the Zhijin Early Cambrian Phosphorite as an Example

Assessment of the Effect of Organic Matter on Rare Earth Elements and Yttrium Using the Zhijin Early Cambrian Phosphorite as an Example

Studies on geochemical characteristics and biomineralization of Cambrian phosphorites, Zhijin, Guizhou Province, China

Selective removal of dolomite from rare earth element‐bearing phosphorite by flotation and leaching and the adsorption mechanism of agents on mineral surfaces

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