The rare earth elements in rivers, estuaries, and coastal seas and their significance to the composition of ocean waters

The aqueous geochemistry of the rare-earth elements and yttrium

Much attention has been paid, in recent years, to the potential application of the Ce anomaly, measured in various marine phases, as a paleoceanographic indicator of widespread marine anoxia. In this paper we present and discuss results from recent studies of present-day rare earth element (REE) distributions (and hence Ce anomaly distributions) in the marine environment which are particularly pertinent to paleoceanography. Subsequently, we review and discuss the validity of the recent literature in which Ce anomalies have been employed as paleoredox indicators.

Application of the Ce anomaly as a paleoredox indicator: The ground rules

The Neoproterozoic oxygenation event: Environmental perturbations and biogeochemical cycling

Crystallization ages of volcanic rocks, dredged or drilled from the Walvis Ridge (ten sites) and the Rio Grande Rise (one site), have been determined by the 40Ar/39Ar incremental heating technique. The fundamentally age-progressive distribution of these basement ages suggests a common hot spot source for volcanism on the island of Tristan da Cunha, along the Walvis Ridge and Rio Grande Rise, and for the formation of the continental flood basalts located in Namibia (Africa) and Brazil (South America). The Walvis Ridge-Rio Grande Rise volcanic system evolved along a section of the South Atlantic spreading-axis, as the African and South American plates migrated apart, astride, or in close proximity to, an upwelling plume. Reconstructions of the spatial relationship between the spreading-axis, the Tristan hot spot, and the evolving Walvis Ridge-Rio Grande Rise volcanic feature show that, at about 70 Ma, the spreading-axis began to migrate westward, away from the hot spot. The resulting transition to intraplate hot spot volcanism along the Walvis Ridge (and associated termination of Rio Grande Rise formation) also involved a northward migration of previously formed African seafloor over the hot spot. Rotation parameters for African motion over fixed hot spots (i.e., absolute motion) have been recalculated such that the predicted trail of the Tristan hot spot agrees with the distribution of radiometric and fossil basement ages along the Walvis Ridge. African absolute motion has been extended to the South and North American plates, by the addition of relative motion reconstruction poles.

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Evolution of the Walvis Ridge-Rio Grande Rise Hot Spot System: Implications for African and South American Plate motions over plumes

Cerium:A chemical tracer for paleo-oceanic redox conditions

Cretaceous Tertiary phenomena in the context of seafloor rearrangements and P(CO2) fluctuations over the past 100 m.y.

Reliability of the reported stability constant for CePO40, as related to Ce redox formulations in seawater

Effect of Binders on Combustion of the Aluminum Powder

Abstract Dioctyl sebacate (DOS), paraffin (PW), fluororubber (FR), and polyurethane (PU) are widely used as binders in aluminized propellants and explosives. In this study, ignition and combustion of aluminum powders coated with DOS, PW, FR, and PU are investigated. The flame speeds of the aluminum powders coated with DOS, PW, and PU are found to decrease with an increase in the content of these binders. The flame speed of the aluminum powder coated with FR is greater than those of the aluminum powders coated with DOS, PW, and PU. In this case, combustion improvement is due to the reaction between the alumina shell and FR.

Y.-G. Liu

Papers

Cerium:A chemical tracer for paleo-oceanic redox conditions

Cretaceous Tertiary phenomena in the context of seafloor rearrangements and P(CO2) fluctuations over the past 100 m.y.

Reliability of the reported stability constant for CePO40, as related to Ce redox formulations in seawater

Effect of Binders on Combustion of the Aluminum Powder

Effect of Binders on Combustion of the Aluminum Powder