Earth Systems and Earth materials
Solar system: Inner planets (Mercury, Venus, Earth, Mars) – rocky planets
Outer planets (Jupiter, Saturn, Uranus, Neptune, Pluto)- gas and ice.
Planets condensed from solar cloud orbiting the sun.
Earth Systems:
Lithosphere the solid earth: (outer rocky crust)
Hydrosphere: includes all types of water and ice
Biosphere: all organic matters dead and alive
Atmosphere: gas surrounding Earth
Most Earth systems closed – except energy from sun
Cycles between and within systems:
Rock cycle
Hydrologic cycle,
Carbon cycle
Earth materials
Elements- periodic table of elements (Appendix 1)
Most rocks rich in Oxygen (O), Silicon (Si), Aluminum (Al) and Iron (Fe).
Earth’s crust is composed of rocks, which are composed of minerals.
Mineral: naturally occurring, usually crystalline substance with a narrow range in
chemical composition. Have characteristic physical properties. Exclude organic
compounds.
Native elements: e.g. copper, gold, carbon (diamond, graphite).
Amorphous minerals: non-crystalline (glassy).
Minerals composed of chemically bonded ions (atoms with electrical charge).
Halite (rock salt) : NaCl
Important mineral groups
Carbonates: CO3 – calcite (e.g. Ca CO3)
Oxides: O – hematite (Fe2O3)
Sulfides; S – Galena (PbS)
Native elements: gold, copper, lead, carbon etc.
Sulfate: SO4—Gypsum Ca SO4
Silicates (most important group) – SiO4 -- Quartz (SiO2)
Most rocks in Earth’s crust composed of silicates
Basic building block of silicates is silicon tetrahedron- SiO4
Isolated tetrahedra, chains, double chains, sheets,
3-D framework
Physical properties of minerals
Hardness (Mohs scale), 1 (talc) – 10 (diamond)
Cleavage: planes of weakness along which the mineral breaks
Crystal shape: cubic, bipyramid etc.
Color not reliable
Rocks
Igneous, metamorphic, sedimentary
Rock cycle: because the Earth is a dynamic planet, the 3 rock types are converted into
each other.
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