The Geochemistry of the Earth - Thanatia: The Destiny of the Earth's Mineral Resources - page 106

Table 5.1 Composition of the main spheres and of the whole Earth (Javoy, 1999)

Mantle Oceanic

crust

Contin.
crust

Core Oceans Atmos. Whole

Earth

% vol 81.89 0.085 0.44 17.56 0.033 1.48E-08 100

%
mass

7 0.072 0.36 32.54 0.023 0.842 ppm 100

O 44.12 44.33 47.25 3 88.889 23.16 30.76

Si 20.89 23.1 27.58 7 16.39

Mg 25.09 4.66 2.65 0.0053 16.82

Al 1.24 8.47 8.36 0.87

Ca 1.49 8.07 4.57 0.0412 1.02

Fe 6.53 8.17 5.13 80 30.43

Ni 0.17 0.3 4.65 1.63

Ti 0.058 0.9 0.42 0.04

Cr 0.169 0.2 0.77 0.36

Mn 0.081 0.11 0.09 0.57 0.24

Na 0.14 2.08 2.37 1.0764 0.10

S 0.01 4 0.0902 1.31

K 0.03 0.12 1.58 0.0398 2.59E-02

U 5E-12 2E-11 1.00E-06 6.96E-12

Th 1.2E-11 4.4E-11 3.50E-06 2.07E-11

Cl 1.9383 4.46E-04

Br
B 0.0005 1.15E-07

C 0.04 0.0028 2.68E-02

N 75.56 6.36E-08

Rare
gases

1.28 1.08E-09

Table 5.1 shows the composition of the main layers on Earth based on Javoy
(1999). Only four elements constitute nearly 95% of the Earth's mass. In order
of abundance, these are O, Fe, Mg and Si. The relative importance of Mg relies
on the geochemistry of the mantle, rather than on the other layers of the solid
Earth. Silicon and iron predominate in the upper crust and core, respectively.
Other estimations were given by different authors such as Mason (1966), Ringwood
(1966), Ganapathy and Anders (1974) and Smith (1979a). All primary upper mantle
compositions agree to within a few percent relative to major and minor elements.
For the core, the composition is not so strictly defined but the general agreement is
on FeNiCoCrMnSiOS combinations. Yet, as stated by Javoy
(1999), the only significant discrepancy between chemical models of the Earth lies
in the lower mantle.
If one only takes into account the outer layers, i.e. the continental crust, hydro-
sphere and atmosphere, these constitute 92.87%, 3.15% and 0.0712% by volume,
respectively.