Geology 1403 Exam #2 Study Notes

This review focuses on major points from Chapters 3 (Minerals), 4 (Igneous Rocks), 6 (Sedimentary Rocks), and 7 (Metamorphic Rocks).
The exam will cover various topics including mineral properties, igneous rock formation, sedimentary processes, weathering, and soil formation.

Parts of an Atom: Protons, Neutrons, Electrons.
Ion: An atom that has gained or lost one or more electrons, resulting in a charge.
- Cation: A positively charged ion.
- Anion: A negatively charged ion.
Ionic Bond: A chemical bond formed through the transfer of electrons from one atom to another, resulting in attraction between oppositely charged ions.
Covalent Bond: A bond formed when atoms share electrons.
Definition of a Mineral: A naturally occurring, inorganic solid with a definite chemical composition and a crystalline structure (five parts: naturally occurring, inorganic, solid, definite chemical composition, orderly crystalline structure).

Crystallization: The process where a solid forms with a well-defined structure; requires a suitable temperature and pressure for crystal growth.
Physical Properties for Identification: Hardness, Luster, Color, Streak, Cleavage.
Mineral Cleavage: The tendency of a mineral to break along defined planes due to its atomic structure.
Stable vs. Metastable: Stability refers to a mineral's resistance to change under specific conditions (metastable means a mineral is stable under certain conditions but could change under others).
Mineral Growth Requirements: Sufficient space, cooling rate, and supersaturation of ions.

Rock Cycle: The continuous transformation between igneous, sedimentary, and metamorphic rocks through various processes (weathering, metamorphism, eruption, burial, etc.).
Igneous Rock: Formed from the cooling and solidification of magma or lava.
Magma vs. Lava: Magma is molten rock beneath the surface; lava is molten rock that reaches the surface.
Partial Melting: Occurs due to differences in melting points of minerals (related to Bowen’s Reaction Series).
Magma Components: Silica, Alumin, Iron, Magnesium, Calcium, Sodium, Potassium, and Trace Elements.
Textural Terms: Aphanitic (fine-grained), Phaneritic (coarse-grained), Porphyritic (mixed), Vesicular (gas bubbles).
Bowen’s Reaction Series: Sequence of mineral crystallization from cooling magma, illustrating the relationship between temperature and mineral formation.

Importance: Provide insights into Earth's history, past environments, and natural resources.
Components: Fragments of pre-existing rocks and minerals, organic materials, and chemical precipitates.
Diagenesis: The physical and chemical changes occurring in sediments after deposition.
Types of Sedimentary Rocks: Detrital (formed from fragments) and Chemical (formed from precipitation).
Weathering Types: Physical (breaking down without changing composition) and Chemical (alteration of minerals).
Soil Formation: Involves weathering, transportation of sediments, and mechanical and chemical alterations.

Soil Horizons: Layers within the soil (O, A, E, B, C horizons).
Zone of Leaching: Upper layers where minerals are washed away.
Zone of Accumulation: Lower layers where leached materials accumulate.
Factors Affecting Soil Formation: Climate (temperature and precipitation), parent material, time, organisms, landscape position.
Pedalfer, Pedocal, Laterite: Soil types related to climatic conditions, forming different profiles based on moisture and temperature.

Metamorphism: Process by which existing rocks are altered by heat, pressure, and fluids.
Protolith: The original rock from which a metamorphic rock forms.
Contact vs. Regional Metamorphism: Contact occurs due to heat from magma, while regional involves pressure and heat over large areas.
Foliation: Alignment of minerals under directed pressure, forming layers in metamorphic rocks.
Metamorphic Index Minerals: Minerals that indicate the conditions of metamorphism (e.g. chlorite, garnet).

Mafic/Felsic: Mafic rocks are rich in magnesium and iron, whereas felsic rocks are rich in silica and aluminum.
Sill, Dike, Pluton, Laccolith, Batholith: Types of igneous intrusions formed from magma below the Earth’s surface.
Fractal Crystallization: Refers to the process where the composition of a melt changes as crystallization occurs, leading to different mineral compositions in rocks.