Geology Midterm Flashcards
Dominant organism of Precambrian
Stromatolites
Dominant Organism of Paleozoic
Trilobites
Dominant Organism of Mesozoic
Dinosaurs
Dominant Organism of Cenozoic
Humans
The Great Dying
Ended Paleozic Era; Siberan Straights erupted
Ending of Mesozoic Era
A Meteor hit earth
Evidence of Ending of Mesozoic Era
iridium in K/T rocks; Shock Quartz; Crater
Era
Due to mass extinction
Period
Due to New dominant species
Epoche
Due to new dominant mammal
Rockslide
Fast; Sedimentary; Rock Slides down bedding plane
Lahar
Fast; Volcanic ash mixed with water; Grey
Mudflow
Fast; Clay mixed with water; Usually in spring due to snow melt; Very fluid
Slump
Slow; Saturation of water causes soil below surface layer to drop downhill; Surface stays intact
Creep
Slow; Slow movement of soil; Due to freeze/thawing; Causes tiliting of objects
Solification
Slow; Top layer melts (in spring), moves slowly over permafrost; In Arctic climates
Main cause of mass movements
Moisture
Factores that affect mass movements (most important first)
- Amount of moisture, adds weight + makes slippery; 2. Angle of Slope; 3. Lack of vegetation; 4. Rock Type, sedimentary are more likely to slide; 5. Roundness (More round= faster)
How to prevent mass movements
Fence/ walls (temperary fix); Leaving enough space; Plant vegetation; Provide good drainage (best way) (Most expensive)
Angle of Repose
Max angle sediments can retain; Larger particle = large angle of repose
Mechanical Weathering
Accomplished by physical forces that break down into smaller + smaller pieces without changing a rock’s mineral composition; Ex: Frost wedging, biological activity, unloading
Chemical Weathering
A chemical transformation of rock into one or more new compounds
Hydrolysis
Chemical Weathering; Rock reacts with acid + water to form clays
Dissolution
Chemical Weathering; Carbonate (rock) and acid rain create calcium carbonate solutions; Sink holes and caves
Oxidation
Chemical Weathering; Rock with O2 or goundwater with Fe is a powerful agent that makes rock red
Weathering of granite
Hydrolysis
Weathering of Basalt
Oxidation
Weathering of Sandstone
Granual disintegration
Weathering of Limestone
Dissolution
Shale weathering
Hydolysis
Tropical weathering
Strong Chemical
Polar + Desert Weathering
Weak chemical + weak physical
Mid-latitude (Michigan)
Strong chemical + strong mechanical
How do caves form?
From dissolution
Usefulness of gravel
drains fast
Usefulness of sand
drains fast
Usefulness of loam
Best for plants; Lots of organics
Usefulness of silt
Poor aeration; Compacts easily
Useflness of clay
absorbs water; Doesn’t let water pass through
How foliation forms
From pressure due to plate collisions
Pressure on Metamorphic rocks
Foliation
Increased heat on Metamorphic rocks
Larger crystals
Hydrothermal solution (chem. Fluids) on Metamorphic rocks
Chemical change
Contact metamorphism
Change due to heat; Small scale; Heat has to come in contact to change rock
Karat
Gold; K/24K x100= % K
Caret
Diamon; 1 c = 1/5 grams
Color of diamond
on D-Z scale; D= best color; Z+ = fancy/rare colored diamonds
Clarity
Loop clan; Eye clean; Slightly included
Loop clean
no imperfections when seen with loupe
Eye clean
No imperfections when seen with naked eye
Slightly included/included
Can see imperfections with eyes
Cut
One of the the 4 c’s human can control; Faceting and cabochoning
Cabochoning
for obq gems
Faceting
For TPT and TLT gems
Round Brilliance
designed to show off diamond
4 C’s
Cut, clarity, color, caret
Intrusive
Igneous rocks that form at depth
Extrusive
molten rock that solidifes at the surface
Magma
molten rock stored in Earth’s crust
Lava
magma that reaches the surface
Mafic rock
low in quartz; dark in color
Felsic rock
high in quartz; light in color
Bowen’s reaction series
Minerals that will cryallize at highest temp: Olivine; Minerals that will crytallize at lowest temp: quartz, mica, k-feldspar
Phoryritic
Igneous rock with two different sized crystals; Two distinct cooling rates
Phaneritic
Coarse grained; slowly cooled magma for 100’s of years
Vesicular
Air bubbles; rapid cooling in minutes/second
Aphanetic
Fine grained; Rapidly cooled in days
Dangers of coal mining
black lung
Reclamation Act of 1977
A company must prove that the land can be reclaimed before mining permits are issued
Mining law of 1872
Authorized the propecting and mining for economic minerals; To promote development and settlement of land in the West
In-Situ Mining
Leaching; Solution mining that uses and acid (cyanide) to dissolve metal
Examles of solution mining
copper, gold, salt, nickel, uranium
Solution mining
uses liquid to dissolve minerals
Pros of Surface mining
Cheaper; Safer; Able to remove more material
Cons of Surface mining
Need alrge area; Hurts enviorment
Pros of Underground mining
Access to valuable ore; Less waste; Can dig in populated areas;; Ability to go deeper
Cons of Underground mining
Ventiliation issues; collapse issues; expensive
Halides
Halogens (Cl,F); Halite, Fluorite
Native Elements
On periodic table; Gold (Au) and Uranium (U)
Oxides
O alone; Hematite, magnetite
Suflides
S; Ex: FeS2; Galena, pyrite
Sulfates
SO4; Gypsum
Carbonates
COO3; Calcite, Dolomite
Silicates
SiO4; Most abundent mineral group
Feldspare
Most common
Diaphanetly
Amont of light that passes through mineral; TPT (Transparent), TLT (Translucent); OPQ
Color
Unrealiable because many minerals come in different colors
Streak
most useful for metallic minerals
Clevage
Way minerals split along planes of weakness; 1: flaky/platy; 2: stairs; 3=90: Cubes/Rectangles
Hardness
1-2: can scratch w/ finger nail; 3-4: Copper penny scratches mineral; 4-5: Iron nail scratches mineral; 5 and greater: Scratches glass
Luster
Amount of light a mineral reflects; Metallic, Nonmetallic vitreous (glass), nonmetallic earthy
Mineral Rules
Must be naturally occuring; Must be inorganic; Must be solid; Must have an orderly internal structure; Must have a definite chemical composition
Rhyolitic Lava
Thick; More explosive
Basaltic Lava
Thin, runny; Quiet
Hot spot
Shield volcano
Divergent
fissure
continent/continent
cinder
Ocean/continent
composite
Shield volcano eruption type
runny lava; quiet
Shield volcano cone shape
wide and big; genlty slopes
Products of shield volcanos
Pahohoe + Aa; Pele’s hair
Cinder eruption type
Gaseous; Erupts once
Cinder Cone shape
Steep, small, and made of scoria
Products of Cinder
Scoria and gas
Caldera
Strato-> massive eruption with pyroclastic flow; Basaltic-> quiet, mainly lava
Composite Eruption type
Explosive; Little lava, mainly pyroclasts; Thick lava; Felsic rocks
Composte cone shape
Large; High viscosity lava; Deep slopes; Layers of pyroclastic +lava
Products of composite
pyroclasts; thick lava; pumic, rhyolite; ash
4 ways sediments turn into sedimentary rock
Compaction; Cementation; Precipitation;Evaportation
Transgression
Sea level rises; Finining upward; 1. Limestone, 2. Shale, 3. Sandstone
Regression
Sea level drops; Coarsing upward; 1. Sandstone, 2. Shale, 3. Limestone
Varves
Dark layers (fine material) (winter) + light layers (coarse material) (Summer); 1 set= 1 year; Usually sandstone
Gradded bedding
Large particles settle out first; High energy to low energy enviroment; deep water
Cross bedding
result of wind or water currents changing direction
Assymetrical ripple marks
Shallow water or wind; Indicated currents direction
Symmetrical Ripple marks
Deep water with no current
Ripple marks
Hard to preserve; Sand + sandstone
Mud Cracks
Form in alternating wet/dry enviroments; Areas called Tidal flats; Sandstone +Shale
Parent rock of slate
Shale
Parent rock of phyllite
Slate
Parent rock of schist
phyllite
Parent rock of gneiss
Schist or granite
Parent rock of jaspillite
Iron formation
Parent rock of quartzite
Sandstone
Parent rock of Marble
Limestone or dolomite
Parent rock of hornfels
basalt or scoria
Parent rock of anthractite
coal
Parent rock of metaconlomerate
conglomerate
Increasing metamorphism (Lowest pressure to highest)
Slate-Phyllite-Schist-Gneiss-Jaspillite
Low degree of metamorphism
Chlorite Muscovite and biotite
High Degree of Metamorphism
Stilimanite
Low viscosity
Runny lava
high viscosity
Thick lava
Calculate mass of ore from a pit
Volume (LWH) x % x Density = mT
1 caret=
.2 grams
Rate of plate movement
Distance/ difference in age
Plates move…
Towards the smallest island (oldest)
Silicate minerals are so common because…
Si + O2 are common elements; Difficult to weather away
What color is a D diamond
Colorless
What color is a G diamond
Light yellow
VS
Referring to clarity; Very slighly included
Volcano high in silica
Composite
A silica poor, iron rich, fine grained volcanic rock
basalt
What lithification process creates sandstone?
Cementation
What lithification process creates limestone?
Precipitation