322 Appendix
A 7 Geochemical Statistics
Chemical Composition of Crust, Ocean, and Atmosphere
o
Si
Al
Fe
Ca
Na
Mg
K
Ti
H
P
CI
N
Ar
Coz
Cont. crust
46.3
28.1
8.2
5.6
4.2
2.4
2.3
2.1
0.6
0.14
0.10
100.0
Ocean crust
43.6
23.9
8.8
8.6
6.7
1.9
4.5
0.8
0.9
0.2
0.14
100.0
Seawater
85.8
0.04
1.1
0.14
0.04
10.7
2.0
tr
99.8
Atmosphere
21.0
78.1
0.9
0.03
100.0
The crust is mainly made of alumuno-silicates, with the alkaline and earth-alkaline elements as
cations, and with iron inside and outside of the silicate minerals. Continental crust has a composition
resembling that of granodiorite, ocean crust that of basalt. Seawater is largely a solution of sodium
chloride. The atmosphere is a mixture of nitrogen and oxygen, both intimately tied to biological
cycling.
Composition of Igneous and Sedimentary Rocks
Si02
Alz03
FeO
Fez03
CaO
NazO
MgO
K20
H2O
TiOz
MnO
P20S
CO2
C(org)
S03
Igneous
(continent)
59.1
15.3
3.8
3.1
5.1
3.8
3.5
3.1
1.1
1.1
0.3
0.1
99.4
Sedimentary
(continent)
57.9
13.3
2.1
3.5
5.9
1.1
2.7
2.9
3.2
0.6
0.1
0.1
5.4
0.7
0.5
100.0
a)Assumed as zero in the calculation.
Tholeiitic
basalt
(deep sea)
50.2
16.2
7.1
2.6
11.4
2.8
7.7
0.2
1.5
0.2
0.1
99.8
Alkali
olivine
basalt
(ocean
volcanoes)
48.2
16.5
7.6
4.2
9.1
3.7
5.3
1.9
2.9
0.2
0.5
99.9
Red clay
(deep sea)
53.7
17.4
0.5
8.5
1.6
1.3
4.6
3.7
6.3
1.0
0.8
0.1
0.4
0.1
100.0