GEOL 102 Minerals and Rocks

Ionic Bonding

Attraction of ions of opposite charge to one another resulting in a neutral charge

Covalent Bonds

When atoms share electrons

Elements

Atoms with the same number of protons. Substances that can't be changed into other substances by normal chemical methods

Minerals

Naturally occurring, inorganic crystalline solids that have a definite chemical composition. Have characteristic physical properties.

Naturally occurring

Excludes manufactured substances such as glass and steel.

Inorganic

Indicating that it is not made from living or fossilized organic material (ie. Amber)

Crystalline Solid

It is made at temperatures and pressures at the Earth's surface, substance in which the atoms are arranged in a regular, repeating pattern

Crystal

solid, bound by smooth surfaces, whose orderly arrangement reflects an internal atomic structure.

Mineraloids

Differ in at least one way to a mineral. (ie Opal - don't have regular crystalline structure)

Chemical Composition

Elemental composition of a mineral and the way in which atoms are bonded. It also determines their characteristic physical properties

Hardness

Relative measure of a mineral's resistance to scratching

Mohs Scale

Hardness scale, higher number scratches lower number.

Lustre

Light reflected from the surface of a mineral

Non-metallic Lustre

Dullest to highest lustre. Earthy - silky - pearly - greasy - resinous - vitreous - specular - adamantine

Diphaneity

Mineral's ability to transmit light.

Transparent

Transmit light freely

Translucent

Transmit light although it may be hard to see through them

Opaque

Does not transmit light at all and appear solid

Colour

Can be misleading with minerals. Impurities can change it and some minerals have several different varients. Opaque minerals can tarnish.

Streak

Colour of a mark that a mineral makes on unglazed porcelain tile when you scratch the tile with a mineral. Always the same, doesn't tarnish.

Feel

Mineral can feel greasy or soapy like talc

Taste

Can have taste, ie halite is salty

Magnetic

Some minerals can attract magnets

Specific Gravity

Weight of a given mineral relative to the weight of an equal volume of water

Chemical Reaction

Ie. hydrochloric acid might make it fizz, like calcite

Fluorescence

Mineral glows under ultraviolet light

Scent

Can smell, ei sulfur

Iridescene

Changes in composition, interfere with light to produce different colours at different angles. Schiller effect. Ie Iridescent Agate and Labradorite

Opalescence

Shattering of light that created iridescent colours on a milky background (translucent, slightly whitish)

Crystal Form

Given an open space, minerals can grow taking on distinct shapes. Minerals crystalline structure is responsible for the outward shape of the crystal.

Cleavage

Tendency to break along preferred planes of weaknes or weak bonds and typically leaves a planar surface when broken.

Fracture

Breaks unevenly. Ie quartz

Crystal Habit

Normal appearance, or general shape, of individual minerals or mineral aggregates that form in nature given an open space

Acicular

Appears as needle-like crystal

Botryoidal

Grape-like rounded forms

Euhedral

Occurs as well-formed crystals showing good external form

Prismatic

Shapes like slender prisms

How Crystals Form

Solidification out of magma or precipitation out of water supersaturated with dissolved ions

Silicate

Mineral that contains SiO2 bound together as tetrahedra

Non-silicate

Doesn't contain SiO2. Oxides, Sulfides, Sulfates, and native metals, Halides, Carbonates, Phosphates. Ie Hematite, Galena, Gypsum, gold, Halite, Calcite, Apatite

Silica Tetrahedra

Composed of one SI and four O. (negatively charged) Ie. Olivine (isolated), Pyroxene (single chain), Amphibole (double chain), Mica (2-D), Quartz and feldspar (3-D)

Non-renewable Resources

Can't be renewed within a human's lifespan. Most raw materials.

Ie. Fossil fuels, oil, gas, potash, iron, uranium, diamonds, and soils.

Feedback Loop

Outputs influence the performance of the system

Positive Feedback Loop

Increases a quantity of the system

Negative Feedback Loop

Dampens a quality of the system, keeps the system more stable

Stratigraphic Record

Layers of rock and their relationships to one another

Formation

Rock layer of the same rock type or a group of associated rock layers that occur over a large area and have a specific geologic age

Contacts

Surface (boundary) between 2 formations

Strata

Layers of sedimentary rock

Stratigraphic Column

Vertical cross-section where the rock layers are divided into stratigraphic formations

Uniformitarianism

Processes operating at the present are the same processes that have operated in the past

Original Horizontality

Beds of Sediment deposited in water were formed as horizontal or nearly horizontal layers. Sedimentary rocks that aren't horizontal have been subjected to some other geological process such as folding or faulting.

Superposition

Within a sequence of undisturbed sedimentary rocks, the layers get younger going from the bottom to the top.

Principle of Lateral Continuity

Erosion can remove sediments, making them discontinuous even though they originated as one continuous unit

Cross-cutting Relationships

Younger features cut across older features. Faults, dikes, and erosion, must be younger than the material that is faulted, intruded, or eroded

Principle of Fossil Succession

Fossils are preserved remains or traces of organisms from the past. A geological time span can be identified by its suite of fossils since different organisms lived during certain time periods, and follow one another in an accepted and recognized order based on decades of research

Inclusions

Fragments of a rock unit that are found enclosed within another rock unit . The rock that supplied the rock pieces must be older than the rock unit within which the pieces are enclosed

Unconformities

Rock layers that are deposited over time mainly without interruption are said to be conformable beds. There is no gap in time in the age of the beds.

Represents a gap in time between preserved beds due to erosion and/or lack of material resulting in no deposition

Angular Unconformity

Tilted bed underlies a horizontal bed

Nonconformity

Break in time occurs between older metamorphic or igneous rocks and younger sedimentary rocks

Disconformity

Gap in time is not readily apparent with horizontal sedimentary beds on either side of the unconformity

Statigraphy

Branch of geology that is concerned with the order and relative position of strata and their relationship to the geological time scale

Zircon

Mineral that forms in igneous rocks that are useful for uranium - lead dating. The lead in zircons mostly comes from radioactive decay of the uranium. Also very resistant to weathering

KAISi3O8

Feldspar (SIlicate)

CaCO3

Calcite

KCl

Halides

FeS2

Pyrite

Ca5(PO4)3

Apatite

Fe2O3

Hematite

Cu

Copper

CaSO4

Gypsum

Mica

Breaks in flat planes, sheets

Galena

Breaks along three planes at right angles to one another, cubic fragments

Rock Cycle

Cycle of processes that occur in the Earth's crust to create and destroy rocks

Rock

A naturally occurring solid mass or aggregate of minerals or mineraloid matter

Sedimentary Basins

Receive dissolved ions and particles produces by weathering

Sediments

Generated through weathering and erosion

Igneous Rocks

Form from melted rock

Extrusive Igneous Rocks

Form when lava erupts at the surface and cools rapidly. Resulting rocks are fine-grained, like basalt, or have a glassy texture

Intrusive Igneous Rocks

Form when magma intrudes into unmelted rock and cools slowly. Slow cooling allows large crystals to grow, coarse-grained, like granite.

Metamorphic Rocks

Heat and/or high pressure recrystallize existing sedimentary or igneous rocks

Igneous Rock

Rock that has formed by the cooling and crystallization (solidification) of molten rock

Magma

Originates deep within the Earth's lithosphere / upper mantle due to the melting of rock and associated minerals

Lava

Name given to molten rock when it reaches the Earth's surface from volcanic activity

Influences on size of a mineral crystal

Rate of cooling, original temperature of the magma, and the crystallization temperature of the mineral the crystal is composed of.

Phaneritic Texture

Visible grains and mineral crystals have an interlocking crystalline texture

Aphanitic Texture

Crystals are too small to see with naked eye

Vesicles

If the solidifying igneous rock contains gas, bubbles of the entrapped gas may form holes as the rock solidifies.

Volcanic Glass

Rapid cooling, or chilling, prevents the crystallization of minerals.

Pumice

Frothed natural glass as a result of excessive gas in the magma

Obsidian

Very rapid cooling forms this natural glass

Equigranular

All mineral crystals are approximately the same size

Porphyritic

Large mineral grains surrounded by a finer-grained groundmass

Gabbro

A mafic, coarse-grained intrusive igneous rock

Granite

Felsic, intrusive, phaneritic, igneous

Rhyolite

felsic, extrusive, aphanitic, igneous

Basalt

Mafic, fine grained, aphanitic, extrusive, igneous

Andesite

intermediate, extrusive igneous rock