first quarter review
DESCRIPTION
TRANSCRIPT
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)