Earth Materials Minerals: The Crystalline State Minerals and Mineralogy Mineral Chemistry Atomic Structure of Minerals Minerals as indicators of the environment of their formation diamondquartzpyrite amethyst asbestos

Plate boundaries and Earthquakes

Supercontinent and Plate Motion Fig. 2.10

Supercontinent and Plate Motion 56 million years ago

Supercontinent and Plate Motion 120 million years ago

Supercontinent and Plate Motion 200 million years ago

Earth Materials Minerals: The Crystalline State Minerals and Mineralogy (p ) Mineral Chemistry (p ) Atomic Structure of Minerals (p ) Minerals as indicators of the environment of their formation (p. 92) diamondquartzpyrite amethyst asbestos

Definition of a Mineral Naturally formed (inorganic)

Definition of a Mineral Naturally formed (inorganic) Solid

Definition of a Mineral Naturally formed (inorganic) Solid Specific chemical composition –What chemical elements are present and in what proportions

Definition of a Mineral Naturally occurring (inorganic) Solid Specific chemical composition Crystal Structure –Ordered arrangement of atoms

Definition of a Mineral Naturally occurring (inorganic) Solid Specific chemical composition Crystal Structure Examples: quartz (SiO 2 ), calcite (CaCO 3 ), halite (NaCl)

Rock is an aggregate of one or more minerals

Polished section ~1 cm

Thin Section

Thin section under ordinary light Magnetite Mica Quartz Feldspar

Thin section under polarized light

What makes each mineral unique? (p.69) Composition What chemical elements are present and in what proportions –QuartzSiO 2 –Olivine (Mg,Fe) 2 SiO 3

What makes each mineral unique? (p.69) Crystal Structure How are the chemical elements packed together Halite (NaCl)

Extremely soft Extremely hard Both minerals are made of carbon (C)

Atomic Arrangement& Physical Properties 3D framework Sheet structure

Elements and atoms Chemical Elements most fundamental substance separated by chemical means Atoms smallest particle of matter retains all properties of an element

Fig. 3.1 Structure of an Atom

Ionan atom with excess charge cationsH + anionsO 2- Chemical Compound electrically neutral comb. of ions water, H 2 OH +, H +, O 2- Ions and Compounds ( p )

Complex ions Combination of ions with a charge Si 4+, O 4 8-  (SiO 4 ) 4- Silicate Ion

Transferring Electrons between atoms Fig. 3.2 Ionic Bonding

Fig. 3.4 Covalent Bonds in Water sharing electrons between atoms

Nature of Bonding and Physical Properties 3D framework Sheet structure Fig. 3.3 and 3.5

The Three States of Matter Solid Liquid Gas Ice in a glacier is a mineral Water in the oceans is not a mineral

Box B3.1 The Three States of Water Controlled by temperature and Pressure

low Temp, High Pressure favors solid state  In Geology, melting is a change of state high Temp, low Pressure favors gaseous state General Rule

Crystal Structure of Minerals (p ) Two factors that control the arrangement of atoms and ions Number of neighboring atoms/ions Size of atom/ion

Galena (PbS) Packing order of atoms

Packing arrangement Polymorphs (p. 79) Diamond Graphite Compounds that occur in more than 1 crystal arrangement

Size of ions of some geologically important ions Size is based on Charge Fig. 3.8

Silicate ion (SiO 4 ) 4- O 2- Si 4+

Ionic Substitution Olivine

Ionic Substitution Olivine Ions of Similar Size and Charge can substitute for each other For example

Ionic Substitution Olivine Mg 2 2+ (SiO 4 ) 4-

Ionic Substitution Olivine Fe 2 2+ (SiO 4 ) 4- Fe 2+ -->Mg 2+ Natural Olivine: (Mg,Fe) 2 SiO 4

Phase diagram Fig Minerals as indicators of their environments of their formation p. 92 Pressure

Fig geotherm

Diamonds from the Mantle Fig. 3.31

Fig. B3.1 Snowball