First Quarter Review

What are the characteristics of a mineral?

SolidInorganic – not livingCrystalline structure/patternDefinite chemical makeup – same

elements/compoundsNaturally occurring – not man-made

How are minerals used?

Ore - valuableGemstones/jewelryNutritionDiamond drill bitsCleaning productsReclamation: fix the land after mining –

return to original or better condition

How are rocks classified?

Texture – mineral grains: coarse, medium, fine

Mineral composition – mixture of more than 1 mineral, sediment

Formation – how they are formed, not where they are found

The Rock Cycle

Continual – no beginning, no endRocks can travel any pathActions between changes… Look for key

words

Sedimentary Rocks

Sediment – bits of rockWEDCC: weathering (breaking down to

create sediment), erosion (moving of sediment), deposition (dropping of sediment), compaction (squeezing of sediment), and cementation (sediment glued together after the evaporation of mineral solution)

Can be formed from any type of rock

Sedimentary Rock Types

Organic – once living material: limestone, coral

Chemical – minerals crystallize out of water - evaporation

Clastic – cemented together: conglomerate, sandstone, silt, shale

Igneous Rocks

Melting, cooling, and hardeningIntrusive: magma – below surface, cools

slowly, large crystals; coarse-grained texture – granite

Extrusive: lava, above surface, cools quickly, small crystals, fine-grained or glassy texture – basalt, obsidian

Stone Mountain - batholith

Metamorphic Rocks

Heat – from mantlePressure – from layers of rock aboveFoliated (banded, layered) and nonfoliated

(nonbanded, not layered)Composition can actually be changedCan be formed from any rock typeGneiss, marble, slate, phylite, schist

Fossils

Remains or traces of once living thingsMold (imprint), cast (rock fills in), petrified

(mineral replacement - forests), amber, tar/asphalt (LeBrea Tar Pits)

Trace fossils – evidence of activity (tail, footprint)

Index fossils – short lifespan, widespread geographically, numerous: trilobite and ammonite

Relative Age/Dating

ApproximateIndex fossils date rock layersSuperposition (older on bottom in geologic

column)Original horizontality – undisturbed Uniformitarianism – gradual, consistent –

past helps us understand present

Absolute Age/Dating

Exact age in yearsRadioactive decay: rate of decay in

radioactive element – unstable to stable (half life)

Carbon-14: on once living organisms (carbon, organic) – up to 50,000 years

Geologic Time

Breaks geologic time into manageable parts: eon, era, period, epoch

Based on changes in fossil evidence (life changes)

Paleozoic (largest mass extinction), Mesozoic (reptiles – dinosaurs), Cenozoic (mammals, now)

Gaps in time – only a few organisms fossilized

Fossil Fuels

From once living organisms; millions of years to form

We rely on themPhotochemical smog (worse in spring,

summer), acidic precipitation (rain), worsens global warming/ozone damage

Nonrenewable - depleting rapidlyCoal, petroleum (oil), natural gas

Alternative Energy

Expensive to implementLess pollutionWind (renewable), biomass (organic,

renewable), solar (Sun’s radiation, photocell, renewable), hydroelectric (Lake Lanier, dam, renewable), geothermal (renewable), nuclear (fission, nonrenewable, radioactivity?)

Conservation

Use lessUse what we do have more efficientlyRecycle Water at night, don’t let the water run,

carpool, turn the lights off, use energy-saver settings on appliances

Causes of Soil Erosion/Pollution

MiningFarmingDeforestationDesertificationBuilding/development (business and

residential)Business/factory wasteHuman litteringVehicles

Soil Conservation

Prevent erosion of soilDust Bowl – loss of topsoil due to erosion

(wind)Cover crops (protect topsoil), contour

plowing, crop rotation (prevent nutrient depletion), terracing (flat sections on hills), windbreaks (slow down wind)