The global geochemical cycle

It was shown in previous chapters that intense hydrothermal activities occurred in the Neogene age in and around the Japanese Islands under the submarine and subaerial environments. In this chapter the influence of these hydrothermal activities on the seawater chemistry, and the global geochemical cycle are considered. 

Implication tor the Origin ot tiuroko and tpithermal Vein-Type mineralizations and the Global Geochemical Cycle... 

The Importance of Iron in the Global Geochemical Cycling of Elements... 

Seafloor hydrothermal alteration processes are important for the global geochemical cycles of many elements, and the record of these processes in the oceanic crust reveals much information about these cycles. Rather robust flux information can be obtained from a variety of elements that have rather low initial abundances in basalt (H2O, CO2, K2O, rubidium, caesium, uranium) or that are rather sensitive to alteration ( Sr/ Sr) and 5 0. Fluxes of many other elements are rather poorly constrained because of substantial primary magmatic variation. 

The first and most important step in the modelling of chemical reactions is to decide whether they are controlled by chemical thermodynamics or kinetics, or possibly by a combination of the two. This also applies to the modelling of more complex chemical systems and processes, such as waste repositories of various kinds, the processes describing transport of toxic materials in ground and surface water systems, the global geochemical cycles, etc. 

A final chapter treats the global geochemical cycling of phosphate, a topic of intense, current geochemical interest. 

Shikazono N (2003) Geochemical and tectonic evolution of arc-back arc hydrothermal systems implication for the origin of kuroko and epithermal vein-type mineralization and the global geochemical cycle. Developments in geochemistry 8. Elsevier, Amsterdam Walther JV, Wood BJ (1986) Fluid-rock interactions during metamorphism, vol 5, Advances in... 

Hudson R. J. M. et al. (1994). Modeling the global carbon cycle Nitrogen fertilization of the terrestrial biosphere and the "missing" CO2 sink. Global Bio-geochem. Cycles 8, 307-333. 

In section 2.3 and in Chapter 3, it is shown that the formation of back-arc basins take important role for the mineralization (back-arc deposits (Kuroko deposits), epithermal Au veins) and global geochemical cycle. Thus, it must be worth considering the formation mechanism of back-arc basins. 

Tajika, E. (1992) Evolution of the atmosphere and ocean of the Earth global geochemical cycles of C,H,0,N, and S, and degassing history coupled with thermal history. Doctoral Thesis, University Tokyo, 416 pp. 

Milliman JD (1993) Production and accumulation of calcium carbonate in the ocean budget of a non-steady state. Global Geochem Cycles 7 927-957... 

Godfrey JD (1962) The deuterium content of hydrous minerals from the East Central Sierra Nevada and Yosemite National Park. Geochim Cosmochim Acta 26 1215-1245 Goericke R, Fry B (1994) Variations of marine plankton 6 C with latitude, temperature and dissolved CO2 in the world ocean. Global Geochem Cycles 8 85-90 Goldhaber MB, Kaplan IR (1974) The sedimentary sulfur cycle. In Goldberg EB (ed) The sea, vol. 4. WUey, New York... 

In the seventies, the growing interest in global geochemical cycles and in the fate of man-made pollutants in the environment triggered numerous studies of air-water exchange in natural systems, especially between the ocean and the atmosphere. In micrometeorology the study of heat and momentum transfer at water surfaces led to the development of detailed models of the structure of turbulence and momentum transfer close to the interface. The best-known outcome of these efforts, Deacon s (1977) boundary layer model, is similar to Whitman s film model. Yet, Deacon replaced the step-like drop in diffusivity (see Fig. 19.8a) by a continuous profile as shown in Fig. 19.8 b. As a result the transfer velocity loses the simple form of Eq. 19-4. Since the turbulence structure close to the interface also depends on the viscosity of the fluid, the model becomes more complex but also more powerful (see below). 

Barenbaum A.A. (2000). Selforganizing mechanisms in global geochemical cycle of the substance on the Earth. Synergetics, 3, 275-295 [in Russian]. 

Walker J. C. G. (1979) The early history of oxygen and ozone in the atmosphere. Pure Appl. Geophys. 117, 498-512. Walker J. C. G. (1986) Global geochemical cycles of carbon, sulfur, and oxygen. Mar. Geol. 70, 159-174. 

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