ERTH 209 Midterm #1

Nebular Hypothesis

The hypothesis which explains the evolution of the solar system, comprised of the Big Bang, followed by a supernova, and finally the creation of a nebula.

Nebular Hypothesis Steps

1. Nebula contracts/rotates

2. Formation of rotating disk

3. Planetesimals form

4. Planets form

Rocky Planets

Mercury, Venus, Earth, Mars

Gas Giants

Jupiter, Saturn, Uranus, Neptune

Earth’s Layering

1. Inner core (solid)

2. Outer core (liquid)

3. Mantle (solid)

4. Crust (continental and oceanic, solid)

Lithosphere

Final layer of the Earth comprised of rock and the crusts. About 5-250 km thick.

Asthenosphere

The lower layer of the crust/middle area of the upper mantle comprised of plastic-like materials. About 300 km thick.

Volcanic Outgassing

Geophysics

The study and prediction of earthquakes and volcanic eruptions, internal structure of the earth, petroleum exploration, etc.

Hydrogeology

The study and exploration of groundwater and surface water reserves and management of drinking water supplies, etc.

Mineralogy

Investigating the composition of minerals in rocks, ore deposits, etc.

Structural Geology

The study of plate tectonics, mapping of rock deformation, petroleum exploration, ore deposits, etc.

Sedimentology

The study of the processes of depositing sediment, petroleum exploration, etc.

Paleontology

The study of the history of life and ancient life, stratigraphic correlation, change through time, etc.

Plate Tectonics

A theory describing the origin, movement, and recycling of the lithospheric plates and resulting landforms. Combines continental drift and seafloor spreading.

Continental Drift Hypothesis

The hypothesis which states that the continents were not always oriented the way they are today, instead having ‘drifted’ into the modern positions.

Pangaea

The supercontinent proposed by Continental Drift Hypothesis which existed 330-200 million years ago.

SONAR

War technology now generalized for oceanic travels. Uses sound and time to measure the depth of the ocean.

Bathymetry

The measurement of the ocean’s depths and the charting of the seafloor.

Seafloor Spreading Hypothesis

The theory that new crust is constantly forming at the Mid-Oceanic Ridge, and old crust is recycled at oceanic trenches.

Mantle Convection

The driver of plate motion as proposed by Hess. Warmer mantle rises and creates a rift valley and colder mantle sinks and creates a trench.

Marine Paleomagnetic Record

Mobile iron particles in magma align with their current field and remain in that position after the magma cools. Symmetrical on either side of the Mid-Oceanic Ridge.

Terrestrial Paleomagnetic Record

Reversals in the polarity at certain intervals within the lava cooled on the side of volcanoes.

Divergent Plate Boundaries

The boundary that occurs when plates move apart and form new basaltic crust, and cause shallow earthquakes and minor volcanism.

Oceanic-Oceanic Divergent Plate Boundaries

Rifting and spreading along a narrow zone in the seafloor has created the Mid-Atlantic Ridge, a mid-ocean mountain chain where volcanoes and earthquakes are concentrated.

Continental-Continental Divergent Plate Boundaries

Rifting and spreading between two plates below land which has created parallel valleys in a zone with volcanoes and earthquakes.

Convergent Plate Boundaries

The boundary which occurs when plates collide. Causes shallow and deep earthquakes, mountain formation, sometimes trenches and volcanoes, and Continental/Island Arcs.

Oceanic-Oceanic Convergent Plate Boundaries

When two oceanic plates collide, they form a deep-sea trench and volcanic island arc.

Continental-Continental Convergent Plate Boundaries

When two continental plates collide, the crust crumples and thickens, creating high mountains and a wide plateau. Ex. Tibetan Plateau.

Oceanic-Continental Convergent Plate Boundaries

When an oceanic plate collides with a continental plate, the oceanic plate subducts and a volcanic belt of mountains is formed at the continental plate margin. Ex. Andes Mountains

Island Arcs

Paths of islands in the ocean which are created by the subduction of an oceanic plate. Form on the overriding plate. Ex. Pacific Ring of Fire.

Wadati-Benioff Zone

Zone of earthquakes that extend away from the plate boundary created by the subduction of an oceanic plate. Depth of the earthquake shows the depth of the plate.

Accreted Terranes

Small crustal masses transported from afar which fuse onto the continent through collision. Seen in sandstone deposits in Western North America.

Transform Plate Boundary

The plate boundary in which two plates slide past each other and cause shallow earthquakes. Valleys and small mountains possible.

Continental-Continental Transform Plate Boundary

When two terrestrial plates slide past each other and create a fault. Ex. San Andreas Fault

Oceanic-Oceanic Transform Plate Boundary

Seafloor spreading centres are offset by mid-ocean ridge transform faults, where the two oceanic plates slide horizontally past each other.

Hot Spots

Areas where shallow earthquakes and volcanoes occur where there is no plate boundary. Caused by a mantle plume (stationary heat source) and proposed by J. Tuzo Wilson.

Mineral Checklist

1. Naturally Occurring

2. Inorganic

3. Solid

4. Ordered Internal Structure

5. Distinct Chemical Composition

Element

A substance that cannot be broken down into simpler substances by chemical or physical means.

Atom

The smallest particle of matter that retains the essential characteristics of an element.

Atomic Number

The number of protons in a nucleus.

Mass Number

The number of protons and neutrons.

Isotopes

Atoms with the same number of protons, different number of neutrons.

Compounds

A substance formed by a chemical combination of two or more elements.

Bonding

The sharing or transferring of elections to attain stable electron configuration.

Ionic Bonding

Transferring elections from one element to another.

Covalent Bonding

The process of sharing elections between two elements.

Silicates

Most common mineral group shaped in a Silicon-Oxygen Tetrahedron.

Silicate: Single Tetrahedron

A type of silicate which has no cleavage and alternates it’s chemical bonding pattern to face or look away from you between Mg/Fe. Called Olivine, gem variety is Peridot.

Silicates: Single Chains

Pyroxene Group: Augite, cleavage at two planes @ 90 degrees.

Silicates: Double Chains

Amphibole Group: Hornblende, cleavage at two planes @ 60 and 120 degrees.

Silicates: Sheet Silicates

Mica Group: Biotite, Muscovite, one plane of cleavage. Used in electronic insulators, paint, cement, etc.

Silicates: Framework Silicates

3D networks of tetrahedra.
Feldspar group: orthoclase, plagioclase, two planes of cleavage at 90 degrees. Used in glass, ceramics, soaps, cement, tarred roofing materials, etc.

Quartz: no cleavage, semi-precious gemstone. Used in glass, paints, abrasives, pressure gauges, etc.

Iron Oxides

Nonsilicates which include iron ore. Ex. Hematite, Magnetite.

Aluminum Oxides

Nonsilicates. Ex. Corundum, which produces gem-quality minerals (rubies, sapphires) and has a hardness of 9.

Carbonates

Nonsilicates which form when metallic or semi-metallic elements combine with carbonate ion. Dissolve in weak acids.

Calcite: Cement, lime, aggregate. Limestone, marble.

Dolomite: Mg-rich limestones.

Sulfates

Light-coloured, low-density nonsilicates.

Gypsum: Evaporite deposits around hot springs and clay beds, used in drywall, wall board, plaster, insulation.

Sulfides

Sulfur and metallic or semi-metallic nonsilicate elements. Ores of lead, iron, zinc, and copper which form in hydrothermal veins. Ex: Pyrite, Galena.

Halides

Nonsilicate minerals which form when a metallic element forms with a halogen (Cl, F, Br, I). Ex: Halite, Fluorite.

Native Elements

Free, uncombined elements. Ex. Metals which are dense, soft, malleable, and ductile. (Gold, Silver, Copper). Ex. Nonmetals which are transparent to translucent. (Sulfur, Diamond).

Moh’s Hardness Scale

1. Talc

2. Gypsum

3. Calcite

4. Fluorite

5. Apatite

6. Orthoclase

7. Quartz

8. Topaz

9. Corundum

10. Diamond

Cleavage

The tendency of a mineral to cleave (break) along planes of weak bonding. Described by the number of planes and the angle of intersection.

Mineral Properties

• Crystal Form

• Luster

• Colour

• Streak

• Hardness

• Cleavage

• Fracture

• Specific Gravity

Crystal Form

The external expression of the mineral’s internal orderly arrangement of atoms. Internal angles remain the same.

Lustre

How light is reflected from the mineral’s surface. May be metallic (pyrite) or non-metallic.

Non-Metallic Lustres

• Vitreous/Glassy (Quartz)

• Greasy (Halite)

• Silky/Pearly (Orthoclase)

• Waxy/Resinous (Talc)

• Earthy (Dolomite)

Colour

The property dictated by what element is bonded within the mineral. Changes how light is reflected through the mineral.

Streak

The colour of the mineral in powdered form. Most useful for minerals with a metallic lustre, checked via streak test. Mineral must be softer than 6-7.

One Plane of Cleavage

Micas, such as Biotite and Muscovite, as well as clay minerals, split along this plane of cleavage.

Two Planes of Cleavage

• Intersecting at 90 degrees: Pyroxenes, Feldspars

• Do not intersect at 90 degrees: Amphiboles

Three Planes of Cleavage

• Intersecting at 90 degrees: Halite

• Do not intersect at 90 degrees: Calcite

Four Planes of Cleavage

Fluorite has an octahedron internal cleavage plane which allows it to form a rhombus when it breaks.

Fracture

Minerals that do not exhibit cleavage when broken. Ex. Quartz (Conchoidal) and Asbestos (Fibrous)

Specific Gravity

The weight of a mineral to the weight of an equal volume of water.

Tenacity

The ability to retain original shape when force is applied.

• Brittle (Quartz)

• Flexible

• Malleable (Gold)

Reaction with Acids

Mineral property that deduces what elements are in the mineral based on how it reacts to an acid. Looking to determine if it’s a carbonate.

Double Refraction

The mineral property which refracts the light as it travels through a mineral.

Unique Properties

• Smell (Sulfur)

• Feel (Talc and Graphite)

• Taste - (Halite)

• Magnetism (Magnetite)

Gems

Minerals which are rare, hard, and chemically resistant.

Refractive Index

The degree to which light is bent.

Dispersion

The ability to split light into different spectral colours.

Igneous Rock

Rocks melt in the hot, deep crust and upper mantle and crystalize.

Sedimentary Rock

The weathering and erosion of rocks exposed at the surface. Rock created through deposition, burial, and lithification.

Metamorphic Rock

Rocks under high temperatures and pressures in the deep crust and upper mantle which recrystallize in a solid state of new minerals.