GE261

Evidence of Plate tectonics 1

Varying thickness of crust

Evidence of plate tectonics 2

Earthquakes

Evidence of plate tectonics 3

Mohorvičić Discontinuity

Alfred Wegner

Rock types, Mountain belts, Fossils fit across great bodies of water, Continental drift

Evidence of plate tectonics 5

Glacial deposits at equator, coral at poles

Crust

Lithosphere Upper, asthenosphere lower

core

Fe + Ni

Mantle

Fe + Mg + Si

Magnetic Reversal

Polens periodically Switch, magnetic reversal is recorded in Rocks

mid Atlantic Ridge

Discovered by submarines in WWII, evidence of seafloor spreading

Magnetic inclination

Vertical angle between line of force and earth’s surface

Magnetic declination

Angle between geographical/True north and magnetic north

Paleomagnetism

A magnetic signature by inclination and declination

Types of plate boundaries

Divergent, convergent, transform

Divergent plate boundary

Volcanoes, earthquakes, Rifts/Vallies, molten material forms volcanoes. ex: cali, iceland, east africa, red sea triple point

convergent margin

ocean to ocean subduction zone, ocean to continent subduction zone, continent to continent subduction zone

subduction zones

feature volcanoes, earthquakes, deep trenches in ocean crust,

transform plate boundary

occur bc earth isnt flat - jagged edges, plates slide past each other, occur on divergent margins,

minerals

naturally occurring inorganic solids with repeating crystalline structure

Quartz Formula

SiO2

Quartz

concoidal fractures, no cleavage, six sided crystal

mineral identification tools

crystal form, cleavage, hardness, color, streak, luster, specific gravity

silicates

most abundant group of minerals on planet, contain SiO4-4. by itself, single chain, double chain, sheets

SiO4-4 by itself

olivine, has Ca, Mg, or Fe

SiO4-4 single chain

pyroxene group, have Ca Mg or Fe. ex Augite, Garnet

SiO4-4 double chains

Amphioble group, have Cu, Mg, Fe. ex Hornblase

SiO4-4 sheets

1:1 clay, 2:1 clay

1:1 clay

1 tetrahedral SiO4-4 + 1 octahedral. Kaolinite

2:1 clay

1 octahedral between 2 tetrahedrals SiO4-4, Smectite group. SWELLS WITH WATER - bad foundation, good water permeable layer

micas

similar to 2:1 clay but Si is replaced with Al and has K between sandwiches, so it doesnt absorb water.