Aluminum oceanic sources

Surface water enrichment is the result of aeolian and fluvial inputs, which are thought to be the most important sources of Th to the ocean. Thorinm-232 has been proposed as a link between the radiogenic thorium isotopes and trace metals and anthropogenic pollutants. " While the pathways are very different for the radiogenic thorium isotopes, Th is delivered to the ocean in a fashion similar to many pollutants and trace metals. For example, Guo et found Th distributions in the Gulf of Mexico and off Cape Hatteras in the North Atlantic Ocean agreed well with the general distribution pattern of aluminum. 

As shown in Table 11.1, hydrothermal emissions are a major source of soluble iron, manganese, and zinc and a minor source of aluminum, cobalt, copper, and lead. Other elements with significant hydrothermal inputs include lithium, rubidium, cesium, and potassium. Considerable uncertainty also surroimds these flux estimates because they are the result of extrapolations from measurements made at a small number of hydrothermal systems at single points in time. These fluxes appear to vary significantly over short time scales as tectonic activity abruptly opens and closes cracks in the oceanic crust. 

Other Sources of Fluorine. M. H. Klaproth discovered that cryolite, the mineral which later came to be used as a flux in the industrial electrolytic production of aluminum, is a fluoride of sodium and aluminum (76). In 1878 S. L. Penfield, in a research consisting of eight analyses of amblygonite, proved that, contrary to the views of Carl Friedrich Rammelsberg, fluorine and hydroxyl can replace each other in the same mineral (155). Traces of fluorine are found in all types of natural water in oceans, lakes, rivers, and springs (156). 

Uncertainties in phenocryst abundance estimates are a significant source of error, particularly for major and highly compatible elements in the main phenocryst phases. In most cases related to ocean drilling samples, phenocryst abundances in a particular sample are rarely known to better than about 5 vol.%. The most abundant phenocrysts are olivine and plagioclase, which contain the elements magnesium, silicon, calcium, aluminum, and nickel. 

The most abundant metals, which exist as minerals in Earth s crust, are aluminum, iron, calcium, magnesium, sodium, potassium, titanium, and manganese (see p. 62). Seawater is a rich source of some metal ions, including Na, Mg and Ca. Furthermore, vast areas of the ocean floor are covered with manganese nodules, which are made up mostly of manganese, along with iron, nickel, copper, and cobalt in a chemically combined state (Figure 20.2). 

Also included in Table 1 is an estimate of the average oceanic residence times for these elements. A shorter residence time indicates a more rapid removal from the oceans. Another way to estimate the relative reactivity of elements with crustal sources is to compare their sea water concentrations with their abundance in the Earth s crust. This is presented in Table 2 (with a normalization to aluminum) and is shown graphically in Figure 1. If variations in the composition of continental materials and differences in the solubility of the elements from these materials are not too great, then to a first approximation the... 

Phosphate rock was formed over millions of years as sedimentary deposits on the ocean floor, mostly as calcium phosphate. There are also igneous forms of this rock. While phosphate rock is mostly calcium phosphate, different sources contain varying amounts of silica, fluorides, sulfates, iron, aluminum, and so on. 

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