Phosphorus sedimentary

The sediment reservoir (1) represents all phosphorus in particulate form on the Earth s crust that is (1) not in the upper 60 cm of the soil and (2) not mineable. This includes unconsolidated marine and fresh water sediments and all sedimentary, metamorphic and volcanic rocks. The reason for this choice of compartmentalization has already been discussed. In particulate form, P is not readily available for utilization by plants. The upper 60 cm of the soil system represents the portion of the particulate P that can be transported relatively quickly to other reservoirs or solubilized by biological uptake. The sediment reservoir, on the other hand, represents the particulate P that is transported primarily on geologic time scales. 

As in the case of igneous processes, the sedimentary processes of rock formation lead to the formation economic mineral deposits. Many valuable mineral deposits of iron, manganese, copper, phosphorus, sulfur, zirconium, the rare Earths, uranium and vanadium owe their origin to sedimentary processes. Some of these constitute special types of sedimentary rocks, while others form important constituents of sedimentary rocks. 

Syn-sedimentary chemical deposits form by chemical and biochemical precipitation of valuable metal components carried in solution, concomitant with the formation of the enclosing sedimentary rock. The manner of such deposition depends on the concentration of the metal in the solvent, the solubility of the precipitating product, the solution chemistry, and the deposition environment. Iron, manganese, phosphorus, lead, zinc, sulfur and uranium are some of the elements that have formed economically valuable deposits by chemical precipitation during sedimentation. 

In the control area, Lombador, the phosphorus, an essential element in plants nutrition, presents, in the relationsoil-plant, a different behavior from the other areas. This can be related to the substratum rock in the Lombador area which is composed of metassediments (turbidites) and are not included in Volcano Sedimentary Complex as the other areas where mining works have occurred. 

Phosphorus is one of the most widely distributed elements on earth. It is found as phosphate salts in nearly all igneous rocks and in sedimentary deposits and sea beds. Phosphorus occurs in more than three hundred minerals, usually associated with Ca, Mg, Fe, Sr, Al, Na, and several other metals, and with anions such as silicates, sulfates, oxides, hydroxides, and hahdes. 

The apatite group minerals are the most abundant phosphorus-bearing minerals on Earth, typically as accessory minerals in basic to acidic igneous rocks, pegmatites, hydrothermal veins and cavities, carbonates, contact and regionally metamorphosed rocks, and sedimentary rocks (Deer et al. 1996). The principal members of the apatite group include fluoroapa-tite (Ca5(P04)3F), chloroapatite (Ca5(P04)3Cl), hydroxyapatite, and carbonate apatite (Ca5(P04, C03)3(F,0H)) (Deer et al. 1996). 

Bedded Ores. These often are composed of oolites of hematite, sidcrite. iron silicate, or less commonly, limonitc in a matrix of sideriie. calcite. nr silicate. They have a wide geographic distribution associated with cither sedimentary rocks. They sometimes contain fossils and line grains of sand. They nften have a fairly high phosphorus content and may he self-fluxing. 

To begin the discussion, we will present briefly a view of the modern carbon cycle, with emphasis on processes, fluxes, reservoirs, and the "CO2 problem". In Chapter 4 we introduced this "problem" here it is developed further. We will then investigate the rock cycle and the sedimentary cycles of those elements most intimately involved with carbon. Weathering processes and source minerals, basalt-seawater reactions, and present-day sinks and oceanic balances of Ca, Mg, and C will be emphasized. The modern cycles of organic carbon, phosphorus, nitrogen, sulfur, and strontium are presented, and in Chapter 10 linked to those of Ca, Mg, and inorganic C. In conclusion in Chapter 10, aspects of the historical geochemistry of the carbon cycle are discussed, and tied to the evolution of Earth s surface environment. 

Phosphorus-rich sedimentary rocks (limestones, mudstones, siltstones) Groundwater from porous rock or from karst features (limestone, dolomite and calcrete) Mainly arid F, U, Rn Irrigated agriculture Mo, Pb... 

Many such studies of sedimentary phosphorus profiles, also incorporating pore water measurement of soluble reactive phosphate, have demonstrated that redox-controlled dissolution of iron (hydr)oxides under reducing conditions at depth releases orthophosphate to solution. This then diffuses upwards (and downwards) from the pore water maximum to be re-adsorbed or co-precipitated with oxidized Fe in near-surface oxic sections. The downwards decrease in solid phase organic phosphorus indicates increasing release of phosphorus from deposited organic matter with depth, some of which will become associated with hydrous iron and other metal oxides, added to the pool of mobile phosphorus in pore water or contribute to soluble unreactive phosphorus . The characteristic reactions involving inorganic phosphorus in the sediments of Toolik Lake, Alaska, are shown in... 

Engle, D. L., and O. Sarnelle. 1990. "Algal use of sedimentary phosphorus from an Amazon floodplain lake Implications for total phosphoms analysis in turbid waters." Limnology and Oceanography 35 487-490. 

Ruttenberg, K. C., and M. A. Goni. 1997. "Phosphorus distribution, (C N P) ratios, and delta 13C in arctic, temperate, and tropical coastal sediments tools for characterizing bulk sedimentary organic matter." Marine Geology 139, 123-145. 

Potential processes that may be called upon to explain the large discrepancy between excess N2 and NOs deficits within the SNM are (1) sedimentary denitrification, (2) anammox, (3) metal (Fe, Mn)-catalyzed denitrification, and (4) non-Redfieldian organic matter mineralization (Codispoti et al., 2001 Devol et al., 2006a,b). The first of these possibilities requires a decoupling between nitrogen and phosphorus cycles (e.g. possible greater burial of phosphorus in continental margin sediments). The less likely additional requirement is that the maximal inputs from the sediments should occur at the same depth as the water column peak of N02. In other words, the exact coincidence of the extrema in NOs , N02, ... 

Compton J., Mallinson D., Glenn C., Eilippelli G., Follmi K., Shields G., and Zanin Y. (2000) Variations in the global phosphorus cycle. In Marine Authigenesis from Global to Microbial, Spec. Publ. 66 (eds. C. R. Glenn, L. Prevot-Lucas, and J. Lucas). Society for Sedimentary Geology, Tulsa, pp. 21-33. 

Guidry M. W. and Mackenzie F. T. (2003) Igneous and sedimentary apatite dissolution and the long-term phosphorus cycle. Geochim. Cosmochim. Acta 67(16), 2949-2963. 

Heterotrophic respiration fueled by the rain of organic matter from the surface ocean is ubiquitous in marine sediments. Its rate determines one of the important characteristics of the sedimentary environment the depth of redox horizons below the sediment-water interface. Heterotrophic respiration is the process by which carbon and nutrients are returned to the water column it is important in the marine fixed nitrogen and sulfur cycles and the accumulation of metabolic products sets the conditions for the removal of phosphorus from the oceans in authigenic minerals. A great deal of effort has been directed toward quantifying the rates, pathways, and effects of metabolism in sediments. 

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