Crust continental

Taylor, S. R. (1964). Abundance of chemical elements in the continental crust A new table. Geochim. Cosmochim. Acta 28,1273-1285. 

Volume 34 Rolf Meissner. The Continental Crust A Geophysical Approach. 

Dewey, J.F. (1980) Episodicity, sequence, and style at convergent plate boundaries. In Strangway, D.W. (ed.). The Continental Crust and Its Mineral Deposits, Geol. Assoc. Canada Special Paper, 20, 553-573. 

In contrast to the southern volcanic zone, Parinacota volcano lies on very thick continental crust (> 70 km) in the central volcanic zone of Chile. Bourdon et al. (2000a) showed that young Parinacota lavas encompass a wide range of U-Th disequilibria. excesses were attributed to fluid addition to the mantle wedge but °Th-excesses in lavas from the same volcano are more difficult to explain. The lavas with °Th-excesses also have low ( °Th/ Th) (< 0.6) characteristic of lower continental crust characterized by low Th/U and in their preferred model. Bourdon et al. (2000a) attributed the °Th-excesses to contamination by partial melts, formed in the presence of residual garnet, of old lower crustal materials. 

Convergent margins are generally considered to be the principle present-day tectonic setting where new continental crust is formed (-1.1 kmVyr, Reymer and Schubert 1984). As illustrated on Figure 23, this new crustal material is characterized by Th/U ratios that are even lower than the Th/U ratio of the MORB mantle (2.6, Sun and McDonough 1989) yet the Th/U ratio of the bulk continental crust (3.9, Rudnick and Fountain 1995) is close to the Th/U ratio of the bulk silicate earth (see Bourdon and Sims 2003). There are several possible explanations for this paradox. Firstly, it is possible that the processes that formed the continental crust in the past were different to those in operation today. Since... 

Taylor SR, McLennan SM (1995) The geochemical evolntion of the continental crust. Rev Geophys 33 241-265... 

Taylor S.R., McLennan S.M. The continental crust Its composition and evolution, Oxford Blackwell, 1985. 

We see that the total element abundance on the continental crust of Earth today (see Figures 1.4 and 1.5), is poorly reflected in the availability of the elements in the sea. Two major reactions affected the availability of the non-metals and the metals apart from abundances both concern solubility of salts ... 

Abundances of chemical elements in rocks, sediments, and the continental crust of China... 

KEYWORDS Elemental abundance, rocks, sediments, continental crust, China... 

The estimated abundances of 76 elements in the continental crust based on... 

The data listed in Table 1 factually reflect abundances of chemical elements in various kinds of geological media of rocks, soils, sediments and in the continental crust of China, because the samples have a good representativity for various media and elements analyzed by high-quality analytical methods under strict quality... 

Yan, M.C. Chi, Q.H. 2005. The Chemical Compositions of the Continental Crust and Rocks in the Eastern Part of China. Beijing Science Press. 171 p. 

Let us first introduce some important definitions with the help of some simple mathematical concepts. Critical aspects of the evolution of a geological system, e.g., the mantle, the ocean, the Phanerozoic clastic sediments,..., can often be adequately described with a limited set of geochemical variables. These variables, which are typically concentrations, concentration ratios and isotope compositions, evolve in response to change in some parameters, such as the volume of continental crust or the release of carbon dioxide in the atmosphere. We assume that one such variable, which we label/ is a function of time and other geochemical parameters. The rate of change in / per unit time can be written... 

Figure 7.15 A simple ocean-atmosphere-continent system. Pressure of C02 enhances Ca release from the continental crust (which is assumed to be made of CaSi03) and controls the depth of calcite saturation. Calcite precipitation is therefore controlled by the hypsometric curve, equation (7.4.8), and Pco2-...

Continental crust is assumed to be made of calcium silicate. High C02 pressure increases weathering and Ca2+ in the runoff according to the fictitious reaction... 

Albarede, F. Brouxel, M. (1987). The Sm/Nd secular evolution of the continental crust and depleted mantle. Earth Planet. Sci. Letters, 82, 25-35. 

Hofmann, A. W. (1988). Chemical differentiation of the Earth the relationship between mantle continental crust, and oceanic crust. Earth Planet. Sci. Letters, 90,... 

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