Geology Exam One

• 1000 b.c.e.– Greeks distinguish stars and planets– Stars rotate around a fixed point– Planēs: “wanderer”
• – What was the Sun? • A burning bowl of oil(A ball of red hot iron)
• Geocentric
• Helicocentric

• 

Ask prof

They made this machine that they noticed the ball would swing at different angles at different types which the swing helped them determin which way out Earth rotated.

• • Big Bang Theory
• – 13.7 billion years ago
• – Explosion of matter from a single point
• – Evidence for the theory
• • Unsolved mysteries
• – Where did matter come from?
• A meterorite
• – Multiple cycles of expansion and collapse

• • When did the expanding begin?
• – All of the mass and energy in the Universe was packed into a single small point
• – 13.7 Ga it exploded and has been expanding ever since
• • A rapid cascade of events.
• – Protons and neutrons formed within 1 second.
• – Hydrogen atoms formed within 3 minutes.
• – Hydrogen fused to form new light elements (He, Be, Li, B) via big bang nucleosynthesis
• After Big Bang
• With expansion and cooling...
• – Hydrogen forms H2
• - The fuel of stars
• – Molecules coalesced into gaseous nebulae

• • Heavier elements– From stellar nucleosynthesis.
• • The mass of a star governs its element production.
• Large mass stars burn more rapidly, are short lived, and create heavier elements up to Iron.
• Small Mass stars burn slowly, burn slowly, live longer, create lower elements up to carbon.
• • A 3rd, 4th or nth generation nebula forms 4.56 Ga• The nebula condenses into an accretion disc
• • Particles coalesce to form planetesimals and stars

• • Our Place
• – Earth is one of nine planets in the solar system
• – The solar system is on an arm of the Milky Way galaxy
• – Our Sun is one of 300 billion stars in this galaxy
• 
• • Small planetoid collides with Earth• Debris forms a ring around the Earth • The debris coalesces and forms the Moon
• 

• Multiple mass, extinctions, 90% of Earth's history is void of complex life, stable oxigenation. 1 billion years ago.
• • Earth is 4.5 billion years old
• – Stable oxygenation 1 billion years ago
• • Life evolves
• – Positions on watch
• • Humans
• – Primitive: 3-4 million years ago
• – Modern: 90,000 years ago
• 

A mineral is a naturally occurring inorganic solid element or compound, with a definite chemical composition and a repetitive internal crystal structure.

• ~ Atoms in a mineral are specifically ordered.
• ~A solid with disordered atoms is called a glass.
• 
• ~Crystalline structure based on atomic patterns.
• 

• ~ Ordered atoms in crystals form a 3-D lattice
• ~ Lattices are patterns that repeat in 3 dimensions
• ~ This internal pattern controls mineral properties• Crystalshape • Symmetry
• 
• ~No it can not be fully seen by the Human eye.
• ~Instrumentation allows us to “see” atoms • A beam of electrons passes through material • Atoms scatter electrons, which pass between them • A shadow on the detector indicates a row of atoms • This principle drives theelectron microscope
• ~X-Ray Diffraction (XRD) probes crystal lattices
• ~Unique lattice spacing is used to ID minerals

• A polymorph is one or two or more minerals with an identical chemical composition but with different arrangements of atoms. Example, diamond and graphite.
• ~Same composition but different crystal structure
• ~Polymorphs reveal the importance of bond type
• ~Diamond and graphite are carbon polymorphs• Diamond–Strongcovalentbonds;hardestmineral • Graphite – Weak Van der Waals bonds; softest mineral
• 

A nucleation point is a pit in a rock or mineral which becomes filled with a carbonite. When these two meet it forms a fissing at the surface. Example, HCL and calcite.

• Luster - vitreous, waxy-greasy, pearly, satiny, earthy/dull, and porcelaneous.
• Color
• Hardness - talc 1, fingernail 2.5, nail 4.5, glass plate 5.5, quartz 7, diamond 10
• Streak - color of residue
• Cleavage - near or at 90 degrees, number of cleavage planes
• Fracture

Near or at 90 degrees, number of cleavage planes

• Silicates - olivine, amphibole, pyroxene, biotite, muscovite, quartz, potassium feldspar, plagioclase fledspar, serpentine
• Carbonates - caclite, dolomite
• Oxide - corundum, hematite, magnetite
• Halaide - halite
• Sulfate/Sulfide - gypsum, chalcopyrte, pyrite, galena, sphalerite
• Native Element - gold, copper

• • Produce a Melt
• – Powdered maficsamples
• – Heat sample until all minerals melt• Cool Sample
• – Allows minerals tocrystallize– Quench at different temperatures
• –Investigate minerals
• 
• Discontinuous Series
• • Growth and Decay
• –A new mineral begins to crystallize at the expense of another
• – Produces an incomplete series
• –Chemistry of the magma changes multiple times
• 
• Continuous Series
• • Complete Series
• –Mineral growth is not at the expense of other crystals
• –Provides an intact record of magma composition through cooling
• –Does not record changes of all chemical elements
• 

• • Contributions to Science
• – Developed the mechanism for the formationof various magmas
• – Intimate understanding of the behavior of mineral crystallization
• – Insight into Earth history

• Plutonic (intrusive) - rocks that form below the Earth's surface.
• Volcanic (extrusive) - rocks that form by being shot out of a volcano.

• Plutonic (intrusive) - rocks that form below the Earth's surface.Volcanic
• (extrusive) - rocks that form by being shot out of a volcano.

• Mafic - composed mostly of pyroxene, calcium-rich plagioclase feldspar and olivine that have relatively high magnesium and iron contents and a relatively low silicon content.
• Intermediate - (e.g., andecite and diorite) and the magmas they crystalize from, that have a composition in between that of mafic and felsic rocks and magmas.
• Felsic - composed mostly of quartz, sodium-rich plagioclase, and potassium feldspars
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• There are different types of magma due to the composition of each type. Explain how it was formed.
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• •Partial melting
• Heat up the rock
• More felsic minerals melt out first
• Transport the melt separating it from more mafic crystals
• Between 2% to 30% of a rock melts under most conditions found in the Earth
• Oppisite of Bowen's Reaction Seires

• Differentiation-Mafic crystals settle, Remaining magma more silicic
• Not Efficient Enough-Process normally can produce an intermediate magma• Rarely extensive enough to make felsic
• 
• • Differentiation
• – Mafic crystals settle
• – Remaining magma more silicic• Not Efficient Enough
• – Process normally can produce an intermediate magma
• – Rarely extensive enough to make felsic

ASK!!!!!

Glassy, vesicular, aphanitic, porphyrtic, phaneritic, pegmatitice, this tells us how and where the rocks were formed.

• • The most important rock type
• – Sedimentary rocks record history
• – What a geologist sees
• – Formations in the Grand Canyon
• • Location of formation
• – Only form at the Earth’s surface
• – Cover 80% of the surface
• – Less than 1% of Earth’s mass

• Clastic
• • “Klastos” – Greek word meaningbroken
• • Sediment = Clasts
• – Where do clasts come from? loose sediment
• – How are clasts made? by combining loose sediment into the 5 step process
• – What process takes loose clasts and makes them into solid rock? Cementation
• Chemical
• • Precipitation
• – Make minerals out of water solutions
• – A major process is evaporation
• • Evaporites
• – 80% of water evaporates = Gypsum
• – 90% of water evaporates = Halite
• • Seawater evaporation
• – 80% of minerals formed are halite
• – 13% of minerals formed are gypsum
• – 7% are carbonates and other salts
• • Chemical Balance
• – Travertine (Chemical Limestone)
• • CO2 degasses from groundwater
• • Water now becomes less acidic
• • Calcium carbonate (Limestone) precipitates
• – Limestone
• • CaCO3
• • WILL REACT WITH HCl
• • Reacting with preexisting rock
• – Limestone turns to dolostone whengroundwater has Magnesium present
• – Silica replacement
• • Dissolved silica begins to replace less stable minerals in a rock
• • Most fossils are not the minerals that make up bone
• • Just like petrified wood
• Biochemical / Organic Rocks
• • Organisms do work
• – Concentrate mineralsin shells and skeletons
• – Can make limestones
• – Biochemical chert
• • Planktonic shells of silica accumulate on the ocean floor
• – Coal and oil shale
• • Contains pure carbon
• • EXTREMELY IMPORTANT
• 

• Step 1: Weathering
• •Breaking up or corroding rock
• 1.Mechanical Weathering
• –Physical break up of pre-existing rock
• –Root wedging, frost wedging, salt wedging, thermal expansion, animal attack
• 
• 1.Chemical Weathering
• –Chemical reactions break down preexisting rock
• –Dissolution, hydrolysis, oxidation, hydration, organic chemical processes
• 
• 
• Step 2: Erosion
• • Sediment removed from rock
• – Follows mechanical weathering
• – Occurs at the start of transportation
• 
• Step 3: Transportation
• • Moving Agent
• – Gravity
• – Ice
• – Water
• – Wind
• – Others?Grain size increases
• • Moving distance
• – Greatly effects what sedimentary rock will eventually form
• 
• Step 4: Deposition
• • End of the road
• – Sediment can nolonger be transported
• – Agent of transport loses the energy to carry sediment farther
• – An accumulation of sediment occurs
• – Leads to lithification
• 
• Step 5: Lithification
• • Making rock
• – Sediment put under pressure by accumulation
• – Squeezes out water and air from sediment voids
• – Compaction of grains
• • Cementation
• – Typically silica or calcite
• – Acts as the glue
• 

No because rocks differ in composition which can increase or decrease the speed of parcipitation.

How far it has traveled

Look at lab book