Scientific Method

Observation

Hypothesis: possible explanation that can explain a set of ovbserbations.

Theory: Scientific ideas supported by an abundance of evidence, passed many test and has failed NONE.

Sometime during the late stages of accretion a Mars-sized body impacted the Earth resulting in: 

1. Ejecting of debris into space.
2. Spped up Earth's rotation.
3. Tilting of the Earths orbited plane to 23 degrees.

Crust: Continental and Oceanic

Mantle: Upper Mantle and Lower Mantel

Core: Outer Core and Inner Core

Contintental Fit

Patterns of present day animal life.

Fossil Evidence

Related Rocks

Ancient Climates

• Wegner lacked a mechanism. He had no way to move the continents.
• He incorrectly beleived that ONLY the continents were moving.
• Continents are not independed plates. 
• Plates are often made of both continental and oceanic lithosphere.

Paleomagnetism from ancient lavas don't align with the present magnetic feild.

Lack of alignment indicates SEAFLOOR SPREADING and new lithosphere was being created pusing old lithosphere apart. 

Divergent:

• Sea Floor Spreading: new oceanic lithosphere is created where partially molten mantel material rises to fill the gap in the rift.
• Rift: A crack like valley which allows molten rock to erupt from below. 
• Decompression Melting: as mantle material rise toward the divergent plate boundary the pressure is reduced which causes melting.

Convergent

• Subduction is where one plate sinks beneath the other plate.
• Deep sea trench: Where plates meet and oceanic plate subducts while continental plate is being pulled lower. 
• Flux melting occurs w/ the oceanic plate, magma rises and creates volcanoes.  

Transform Boundaries

• Generates earthquakes. 

Flux melting is melting due to additon of volatiles (ex. sugar cube and water). This occurs at subduction zones, convergent plate boundaries. Oceanic crust is destroyed and new continetal crust is created due to accretion. 

• SOLID
• Naturally Occuring
• Homogenus 
• Inorganic (NO organic carbon)
• Crystalline solid: atoms are arranged in a particualar structure.
• Specific chemical compound. 
• Minerals formed with 1+ element.

Different versions of an element. Have the same atomic number but a different atomic weight. 

EX. All carbon atoms have 6 protons. The atomic mass=6. Protons(6)+Neutrons(6)=12.

Number of neutrons may change=isotope --> Carbon 13 (7 neutrons) (6 protons)

• Transfer of electrons. 
• Form when shells are nearly empty or nearly full. 
• Weak bond.

• Sharing of electrons
• Form when shells are about half full
• Strong bond.

• Atoms combine (bond) by losing, gaining, or sharing electrons to form minerals. 

• Chemical reactions between elements.
• Crystallization: the growth of a solid from a gas or liquid whose constitutents come together in the proper chemical proportions and crystalline arrangement. (i.e. ICE)

• Lower temperature of a liquid below its freezing point. 
• Liquids evaporate from a solution forming a supersaturated solution and results in precipitate.
• When atoms and ions in a solid become mobile and rearrange themselves at high temperature (>250°C)

What determines what minerals will form?

• Available elements.
• Ionic substitution.
• Conditions of crystallization. Ex: Diamond vs. Graphite

Silicates. 

Carbonates, Oxides, Suflides, Sulfates, Native Elements. 

What makes a gem: 

1. Beauty: reflected by color
2. Transparency
3. Brilliance: enhanced by cutting and polishing.
4. Durablitltiy: Based on hardness.
5. Rarity or perceived rarity. 

• Covalent bonds. 
• Polymorph of carbon along with graphite. 
• brought to surface quickly through Kimberlie pipes. 

Intrusive: Igenous rocks are formed underground deep within the earth when magma becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igenous rock. 

Extrusive: formed when volcanoes erupt, causing the magma to rise above the earths surface (lava) and cools above the surface. 

1. Raise temp (deper in the Earth the higher the temp)- "heat transfer melting"
2. Lower the pressure- "decompression melting"
3. Add volatiles- H20, CO2 etc. "flux melting" lowers melting temperature.

Partail Melting

• Rock are composed of different minals.
• Minerals melt at different temperatures.
• Only a fraction of a rock might melt, depending on the temperature and pressure conditions. 

Low 

• Felsic
• Intermediate
• Mafic
• Ultramafic

High

High Silica

Felsic >65% 

Intermediate 45-65% 

Mafic 45-55% 

Ultramafic <40% 

Low Silica

SILICA

ex. Felsic has high silica content (>65%) and the melting temperature is the lowest (600-800°).

resistance to flow.

High Resistance to flow

(Low melting temperature)

Felisc

Intermediate

Mafic

Ultramafic

(High Melting Temperature)

Low Resistance to flow

ex. honey: heated up it moves quicker

ex. Felsic has high vicosity because it is lower in temperatur

progressive crysal formation and settling.

progressively extracts iron and magnesium from the magma so the remaining magma becomes more felsic. 

Iron Composition in rocks 

High Silica=Low Iron

Low Silica=High Iron 

Low Iron

(High Silica)

Felsic

Intermediate

Mafic

Ultramafic

(Low Silica)

High Iron 

Horizontal Intrusions

(ex. window sill)

Vertical or semi-vertical intrusion.

• Gentle Eruptions
• Lava dominates
• magma/lava generally low in silica (mafic)
• low viscosity (resistance to flow)
• release gas
• occur commonly at divergent boundaries and hot spots
• ex. Kilauea, Hawaii; Mid-Atlantic Ridge

• Violent eruptions
• Mostly pyroclasics
• Lava high in silica (intermediate to felisc)
• High viscosity (resistance to flow)
• Gas is trapped
• Occur commonly at convergent boundaries and hot spots. 

Effusive: flood basalts

Pyroclastic: composite volcanoes, cinder cones, calderas.

Centeal Eruption: shield volcanoes, cinder cones, spatter cones. 

• primarily fissure eruptions
• mafic lava
• generally flat layers
• cover 100-1000's of km²
• ex. Columbia River Basalts

• Central vent filled from previous eruption.
• Pyroclastic layers, lava flows.
• Radiating dikes. 
• Ex. Mount Fuji (Japan)

• ex. Cascande Volcanoes (Mt. Ranier, Mt. St. Helens, etc.)
• Volcanoes of the Japan Ocean Island Arc
• Andes Volcanoes (think of ande's mints and how they are made up of layers) 

Calderas

• Central Vent
• Extremely large explosive eruption cas the COLLAPSE of the summit into an empty magma chamber.
• Primarily felsic pyroclastic rocks (low iron, high silica)
• 10s Km across
• Ex. Crater Lake, Yellowstone NP

• Basaltic Lava (Mafic)
• Pahoehoe-ropey
• Aa-blocky
• Lava Tube
• Pillow lava-shperical shape, characteristic of underwater volcanic eruptions.
• Columns.