THE DISTRIBUTION OF CALCIUM CARBONATE IN DEEP SEA SEDIMENTS

1974 ◽  
pp. 58-76 ◽  
Author(s):  
A. T. S. RAMSAY
Keyword(s):  
Calcium Carbonate ◽  
Deep Sea ◽  
Deep Sea Sediments

Enhanced erodibility of deep-sea sediments by presence of calcium carbonate particles

2020 ◽  
Vol 40 (5) ◽  
pp. 559-571
Author(s):  
Jun Young Seo ◽  
Sun Min Choi ◽  
Ho Kyung Ha ◽  
Kyung Eun Lee
Keyword(s):  
Calcium Carbonate ◽  
Deep Sea ◽  
Deep Sea Sediments

scholarly journals Mechanism and Influencing Factors of REY Enrichment in Deep-Sea Sediments

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 196
Author(s):  
Jiangbo Ren ◽  
Yan Liu ◽  
Fenlian Wang ◽  
Gaowen He ◽  
Xiguang Deng ◽  
...  
Keyword(s):  
Deep Sea ◽  
Research Progress ◽  
Bottom Current ◽  
Knowledge Map ◽  
P2o5 Content ◽  
Deep Sea Sediments ◽  
Potential Resource ◽  
And Migration ◽  
Adsorption Desorption ◽  
Sediment Interface

Deep-sea sediments with high contents of rare-earth elements and yttrium (REY) are expected to serve as a potential resource for REY, which have recently been proved to be mainly contributed by phosphate component. Studies have shown that the carriers of REY in deep-sea sediments include aluminosilicate, Fe-Mn oxyhydroxides, and phosphate components. The ∑REY of the phosphate component is 1–2 orders of magnitude higher than those of the other two carriers, expressed as ∑REY = 0.001 × [Al2O3] − 0.002 × [MnO] + 0.056 × [P2O5] − 32. The sediment P2O5 content of 1.5% explains 89.1% of the total variance of the sediment ∑REY content. According to global data, P has a stronger positive correlation with ∑REY compared with Mn, Fe, Al, etc.; 45.5% of samples have a P2O5 content of less than 0.25%, and ∑REY of not higher than 400 ppm. The ∑REY of the phosphate component reaches n × 104 ppm, much higher than that of marine phosphorites and lower than that of REY-phosphate minerals, which are called REY-rich phosphates in this study. The results of microscopic observation and separation by grain size indicate that the REY-rich phosphate component is mainly composed of bioapatite. When ∑REY > 2000 ppm, the average CaO/P2O5 ratio of the samples is 1.55, indicating that the phosphate composition is between carbonate fluoroapatite and hydroxyfluorapatite. According to a knowledge map of sediment elements, the phosphate component is mainly composed of P, Ca, Sr, REY, Sc, U, and Th, and its chemical composition is relatively stable. The phosphate component has a negative Ce anomaly and positive Y anomaly, and a REY pattern similar to that of marine phosphorites and seawater. After the early diagenesis process (biogeochemistry, adsorption, desorption, transformation, and migration), the REY enrichment in the phosphate component is completed near the seawater/sediment interface. In the process of REY enrichment, the precipitation and enrichment of P is critical. According to current research progress, the REY enrichment is the result of comprehensive factors, including low sedimentation rate, high ∑REY of the bottom seawater, a non-carbonate depositional environment, oxidation conditions, and certain bottom current conditions.

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