1. Background: Geology http://www.answers.com/Geology
Geology - The scientific study of the origin, history, and structure of the earth - The Science of the Earth Different disiciplines of Geology - Historical discovers the past - Physical understanding the processes that operate on and inside Earth
Earth’s Internal Structure
- Crust
- The outermost solid layer of Earth
- Mantel
- the thick shell of dense, rocky matter that surrounds the core
- Core
- center & densest part
- largely metallic iron
- Atoms of Elements
-Formed in Solar Nebula
- Minerals
-General chemicals compound formed by geological process
- Rocks
- general combination of minerals
- Core Fe + Ni
- Mantle O + Si + Mg
- Crust O + Si

2. plate tectonics
theory that unifies many of the features and characteristics of continental drift and seafloor spreading into a coherent model and has revolutionized geologists' understanding of continents, ocean basins, mountains, and earth history.
plate tectonics theory holds that the lithosphere, the hard outer layer of the earth, is divided into about 7 major plates and perhaps as many as 12 smaller plates, c.60 mi (100 km) thick, resting upon a lower soft layer called the asthenosphere. Because the sides of a plate are either being created or destroyed, its size and shape are continually changing. Such active plate tectonics make studying global tectonic history, especially for the ocean plates, difficult for times greater than 200 million years ago. The continents, which are c.25 mi (40 km) thick, are embedded in some of the plates, and hence move as the plates move about on the earth's surface.

3. Types of Plate Boundaries
Compression
- compacts a block of rock & squeezes it into less space
- causes shortening
- reverse fault
- convergent boundary
Tension ( also called dilation)
- Pulls a rock apart and inc. its length
Causes lengthening
Normal fault
Divergent boundary
Shear
-Smears a block of rock and may eventually tear it apart into blocks of rock that slide past one of another along a strike-slip fault
Neither lengthening or shortening
Strike-slip fault
Transform boundary

4. Minerals
Inorganic, naturally occurring substances that have a characteristic chemical compound,
distinctive physical properties and crystalline structure
Crystalline structure
Is an orderly 3-D arrangement of atoms or molecules
General. Mineral Properties
Color
Luster
Is a des. Of how mineral surfaces reflect light
Metallic
Silvery, gold or brassy sheen
Nonmetallic
Luster unlike that of metal
Streak
Is color of substance after it has been ground to a fine powder
Metallic -Hematite
Hardness
- Measure of resistance to scratching mohs scale of hardness

5. Cleavage and Fracture
Cleavage surfaces occur as sets of parallel surfaces of weak chemical bonding ( attraction) between repeating, parallel layers of atoms in a crystal
Excellent cleavage
Direction reflects light in one direction from a set of obvious, lg, flat and even surfaces
Good cleavage
Directions reflects light in one direction from a set of many small, obvious, flat, but uneven surfaces
Poor Cleavage
Direction reflects light in one direction from a set of flat, uneven surfaces that are inconspicuous compared to the fracture surfaces
Most light is scattered randomly by the fractured surfaces
Fractured surfaces of some irregular masses can be described as
uneven
splintery (like splintered wood)
hackly ( jagged edges)
conchoidal fractures
smoothly curved fractures
opal and pure quartz

6. Rocks
Igneous Rocks
are rocks that form when magma or lava cool to a solid form, either glass or masses of intergrown mineral crystals
Common Igneous Rock Textures
Glassy
Completely lack grains
Vesicular texture
Have bubbles
Have solutions cavities (cave-like spaces)
Fractures
Irregular spaces b/t poorly sorted grains of diverse size
Randomly oriented small crystals: fine- grained crystalline texture
Grains gen. <1mm and too small to identify without a hand lens
Randomly oriented large crystals: coarse-grained crystalline texture
Grains gen. >1mm & lg enough to identify unaided
Extrusive vs. Intrusive
Extrusive
Igneous rocks that form at the planets surface
Extruded or violently ejected onto the surface through volcanoes
Intrusive
A body of magma that pushes its way into the Earth’s crust is Intrusive
Rocks that form by the cooling of intrusions
Felsic vs. Mafic
Felsic
Gen. light-colored
Quartz and potassium feldspar most abundant minerals
Mafic
Dark-colored
Proxene and plagioclase most abundant minerals

7. Sedimentary Metamorphic Rocks
are rocks formed when fragments of plants, animals, or rocks are compressed together or otherwise hardened; or they are masses of intergrown mineral crystals that precipitated from water( like the rock salt that remains when the ocean water is evaporated)
Common Sedimentary Rock Textures
Clastic texture: contain clast (fragments) of minerals, other rocks, plants, or animals
Detrital worn rock fragments
Silty detrital (clastic) texture
Sandy detrital (clastic) texture
Layered crystalline texture
Coarse-grained detrital (clastic) texture
Metamorphic
Metamorphic Rocks
are rocks changed from one form to another (transformed) by intense hear, intense pressure, or the action of hot fluids.
Common Metamorphic Rock Textures (p. 69)
Crystalline texture: glittery when rotated in bright light
Equigranular crystalline texture
Equingranular: all about the same size
Folded texture
Foliated small crystals and shiny reflection
Foliated: layered alighnemnt of flat-sided mineral grains so they are parallel to one another giving the appearance of folio-like (leaf-like)
Foliated equigranular crystalline texture

8. Green house effect
the property of the Earth’s atmosphere by which long-wavelength heat radiation from Earth’s surface is trapped or reflected back by the atmosphere
Earth’s climate system consists of 4 interacting subsystems
Atmosphere
hydrosphere
lithosphere
biosphere
solar energy drives the system
some of the incoming radiation is reflected back into space from the clouds, atmospheric pollutants, ice , snow and other reflective surfaces

9. Tectonic movement affect
surface relief
which influences atmosphere circulation
the geometry of continents and ocean basins
which controls ocean circulations and location of ice sheets
while volcanic and industrial gasses affect atmospheric composition
The Carbon Cycle
Natural fluxes of Carbon b/t the atmosphere, hydrosphere, biosphere, crust and mantel
1. carbon enters the atmosphere through volcanism, weathering and biological respiration and decay of organic matter in soils
2. photosynthesis incorporates carbon in the biosphere from which it can become part of the crust if buried w/accumulating sediment
subduction liberates carbon from oceanic crust into the mantel
anthropogenic activities release carbon to the atmosphere through fossil fuel-fuel use, combined w/deforestation and burning wood
The Greenhouse Gases
some of the short-wave (visible solar) radiation reaching Earth is absorbed by the land and oceans, while some reflects back
Earth also radiates long-wave radiation (infrared) back to space.
Greenhouse gases trap some of the outgoing long-radiation, causing the atmosphere to heat up
W/inc. conc. Of these trace gases, the air temp of the lwr atmosphere rises.
Historical Temperature Changes
- Hemispheric and global temp changes since the mid-nineteenth century (w/both land and ocean data)
- long term trend is a rise of temp,
- interval being about 0.6 degrees C