Chapter 3
Secondary Minerals
Abstract This chapter introduces secondary minerals such as clay minerals,
hydroxides and oxides in soils. Clay minerals, which are major secondary minerals
in soils, are phyllosilicates that have 1:1 or 2:1 type layers. The 1:1 type minerals are
kaolinite and halloysite. The 2:1 type minerals are smectite, vermiculite, micaceous
minerals, and chlorite. Gibbsite and manganese oxides are introduced as examples of
hydroxides and oxides, respectively. This chapter also constitutes the basic part of
treatment of the inorganic constituents in soils. Secondary minerals have an effect on
the chemical, physical, and biological functions of soils. As the size of secondary
minerals is approximately 2 μm or less, electron micrographs and X-ray diffraction
(XRD) are effective for characterizing these minerals. Schematic diagrams are used
to interpret the chemical structure of phyllosilicate clay minerals.
3.1 Introduction
The secondary minerals in soil are minerals that are stabilized under various soil
environments. The major secondary phyllosilicates in soil are summarized in
Table 3.1 with their idealized chemical formulae (Deer et al. 2013). Formula units
in association with O 5 (OH) 4 and O 10 (OH) 2 are also used for 1:1 and 2:1 type
phyllosilicate minerals, respectively (Kodama 2012). The major oxides, hydroxides,
and other relevant minerals in soil (Kampf et al. 2012) are summarized in Table 3.2.
This table includes minerals described in other chapters. Other non-crystalline
secondary and primary inorganic materials in soil are described in Chap. 4. These
minerals and materials in soil can be altered further if environmental conditions
change.
Environmental factors that affect the behavior of secondary minerals include
water, temperature, redox condition, biological activities, and time (Churchman
and Lowe 2012). In addition, human activities affect secondary minerals and
materials through agricultural soil management, civil engineering, and other activities. As examples, the dry–wet cycle affects the shrink–swell behavior of smectitic
soils, and the exchangeable cation composition of secondary minerals is easily
affected by application of a fertilizer, inundation of seawater, etc. Changes in
© The Author(s) 2018
M. Nanzyo, H. Kanno, Inorganic Constituents in Soil,
https://doi.org/10.1007/978-981-13-1214-4_3
37
Secondary Minerals
Abstract This chapter introduces secondary minerals such as clay minerals,
hydroxides and oxides in soils. Clay minerals, which are major secondary minerals
in soils, are phyllosilicates that have 1:1 or 2:1 type layers. The 1:1 type minerals are
kaolinite and halloysite. The 2:1 type minerals are smectite, vermiculite, micaceous
minerals, and chlorite. Gibbsite and manganese oxides are introduced as examples of
hydroxides and oxides, respectively. This chapter also constitutes the basic part of
treatment of the inorganic constituents in soils. Secondary minerals have an effect on
the chemical, physical, and biological functions of soils. As the size of secondary
minerals is approximately 2 μm or less, electron micrographs and X-ray diffraction
(XRD) are effective for characterizing these minerals. Schematic diagrams are used
to interpret the chemical structure of phyllosilicate clay minerals.
3.1 Introduction
The secondary minerals in soil are minerals that are stabilized under various soil
environments. The major secondary phyllosilicates in soil are summarized in
Table 3.1 with their idealized chemical formulae (Deer et al. 2013). Formula units
in association with O 5 (OH) 4 and O 10 (OH) 2 are also used for 1:1 and 2:1 type
phyllosilicate minerals, respectively (Kodama 2012). The major oxides, hydroxides,
and other relevant minerals in soil (Kampf et al. 2012) are summarized in Table 3.2.
This table includes minerals described in other chapters. Other non-crystalline
secondary and primary inorganic materials in soil are described in Chap. 4. These
minerals and materials in soil can be altered further if environmental conditions
change.
Environmental factors that affect the behavior of secondary minerals include
water, temperature, redox condition, biological activities, and time (Churchman
and Lowe 2012). In addition, human activities affect secondary minerals and
materials through agricultural soil management, civil engineering, and other activities. As examples, the dry–wet cycle affects the shrink–swell behavior of smectitic
soils, and the exchangeable cation composition of secondary minerals is easily
affected by application of a fertilizer, inundation of seawater, etc. Changes in
© The Author(s) 2018
M. Nanzyo, H. Kanno, Inorganic Constituents in Soil,
https://doi.org/10.1007/978-981-13-1214-4_3
37