GEOLOGY MIDTERM REVIEW

HEMATITE Red streak Metal Heavy

magnetite Magnetic Heavy Metallic Black streak

plagioclase Scratches glass White 2 directional cleavage

Olivine Green- always Hard Crystalizes at highest temp. –First to form from a melt

gypsum Soft 1-2 Clear= selenite Opaque= alabaster Chalky feel

pyrite Fool’s gold Metal

halite Salty 3= 90 cleavage soft

galena 3= 90 cleavage Metal heavy

hornblende Black- always Hard- 5-6 Two directional cleavage

talc Softest mineral Greasier feel than gypsum

calcite Fizzes 3 ≠ 90 cleavage Double refraction Soft Main mineral in limestone and marble

K-feldspar Pink Scratches glass 2= 90 cleavage

muscovite Flakey- 1 directional cleavage Light in color

corundum Extremely hard= 9 May have hexagonal crystals Red= ruby Blue= sapphire

quartz Most common mineral Scratches glass NMV Hexagonal crystals Rock crystal- tpt All others- tlt

fluorite Soft Many colors; purple and green 4 directional cleavage

graphite Pencil “lead” Soft metal

biotite Dark color One directional cleavage Part of the mica family

chalcopyrite “bronzier” than pyrite –More of an orange color Contains copper Black streak

IGNEOUS ROCKS

GRANITE Intrusive igneous Cooled slowly Felsic Has quartz, plag., biotite, K-feld, hornblende Formed underground (dikes, sills, batholiths)

Andesite Extrusive intermediate Usually porphyritic Composite volcanoes

pumice Felsic Extrusive Composite volcanoes vesicular

basalt Extrusive Mafic Shield volcanoes From runny lava flows Pahoehoe and Aa are types of basalt

gabbro “black granite” Intrusive Mafic Formed underground (dikes, sills, batholiths) Granite’s mafic cousin

scoria Vesicular Mafic From cinder volcanoes Pumice’s “mafic cousin”

obsidian Felsic (even though dark) 99% quartz Conchodial fracture Cools on top of felsic lava flow

periodotite Mafic intrusive\ Contains olivine

rhyolite Felsic Composite lava flows

SEDIMENTARY

Crystalline limestone Fizzes Chemical precipitate Forms in deep ocean From dissolved shells fossiliferous

Rock gypsum Evaporite soft

shale Fine clastic From mud

sandstone Gritty From beach/desert clastic

coal Bioclastic From swamps Organic lightweight

chalk Soft Bioclastic (forminifera) fizzes

arkose High in K-feldspar Sandstone clastic

coquina Bioclastic Made of shells Forms near reefs

Conglomerate Fast moving river Breccia Alluvial fan

flintChert

Metamorphic

slate Metamorphosed shale Foliated Parent rock: shale

Gneiss Banded (striped) Foliated Parent rock- granite

marble Can be many colors Metamorphosed limestone Not foliated Will fizz (calcite)

Quartzite Metamorphosed sandstone Non foliated Will scratch glass Any color

Schist Foliated Highly reflective May have garnets

metaconglomerate

OTHER STUFF

Solution Mining

Silicate structures why common?

1 carat=.2 grams 50 cts= grams 25 grams= carats

Geodes Form from precipitation of quartz in a hollow opening

Gold % Divide by 24 (pure gold)

Rock cycle

viscosity Rhyolite High viscosity (thick) Explosive eruption Basalt Low viscosity (runny) Quiet eruptions

lithification Precipitation Evaporation Cementation compaction

oxidation

dissolution Usually limestone Acid rain Forms caves/sinkholes

caves

CLIMATE TROPICAL –Strong chemical DESERT –Slight mechanical POLAR –Slight mechanical MID LATITUDE (MI) –Strong chemical and mechanical

TYPES OF SOIL Sandy- drains fast Clayey- absorbs water; doesn’t let water pass through; poor for house foundations Loamy- best for plants

transgression Rise in sea level regression Drop in sea level