56
Review Mid)Term Exam #1
Review&
Mid)Term&Exam&
Learning&Objec9ves&–&Chapter&1&
• I&can&describe&fundamental&characteris9cs&of&
planet&Earth&
• I&can&explain&the&scien9fic&method&and&why&
the&science&of&geology&is&important&in&our&daily&
lives&
Fundamental&characteris9cs&of&Earth&
1. You&will&inherit&Earth&
2. Earth&scien9sts&use&cri9cal&thinking&including&&repeatable&observa9ons&and&testable&ideas&to&understand&Earth.&Any&other&method&is&based&on&faith.&
3. Earth&is&4.6&billon&years&old.&
4. Earths&surface&is&a&complex&system&of&interac9ng&rock,&water,&air,&and&life.&
5. Earth&is&con9nuously&changing.&
6. Earth&is&the&water&planet.&
7. Life&evolves&on&a&changing&planet.&Life&con9nuously&modifies&Earth&and&Earth&con9nually&modifies&life.&
8. Humans&depend&on&Earth&for&natural&resources.&
9. Natural&hazards&pose&risks&to&humans.&
10. Humans&significantly&alter&Earth&and&climate&is&changing.&
Peak%oil%–%We%probably%won’t%“run%out”%of%oil.%But%it%is%likely%to%get%very%expensive.%
Global%warming%–%How%quickly%will%warming%proceed%and%what%are%the%potenDal%consequences?%
Soil%erosion%–%It%is%esDmated%that%65%%of%Earths%soil%is%degraded%by%erosion,%deserDficaDon,%and%salinizaDon.%
Fresh%water%–%Around%the%world%drought,%and%overuse%threaten%water%resources.%
Economic%minerals%–%Mineral%resources%are%finite%and%increased%demand%can%make%some%of%them%unaffordable.%
Can%you%think%of%other%global%challenges?%%%%%
Humankind%is%faced%with%global%challenges.%How%will%we%manage%them?%
Learning&Objec9ves&–&Chapter&2&
• I&can&describe&Earth,&the&Sun&and&other&objects&of&the&Solar&System&and&their&chemical&
differences.&
• I&can&explain&the&Solar&Nebula&Hypothesis.&• I&can&discuss&the&sources&of&heat&to&early&Earth&and&the&consequences&of&heat&buildup&
&
&
&
&
&
&
Terrestrial%planets%are&small&and&rocky,&with&thin&atmospheres,&
silicate&and&metallic&shells.&
&&
&O,&Fe,&Si,&Mg,&Ca,&K,&Na,&Al&
%MERCURY%%%%%%%%%% %%%%%%%%VENUS%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%EARTH%%%%%%%%%%% %%MARS%
Gas&Giants&are&massive&planets&with&thick&
atmospheres.&&
He, H, CO2, H2O, N2, CO, NH3, CH4&
Jupiter&
Saturn&
Uranus&
Neptune&
Because the solar nebula was rotating, it contracted into a disc, and the planets formed with orbits lying in
nearly the same plane.
Nebula Collapse and Condensation Rotation started by shockwaves from a nearby explosion (?)
Planetesimal accretion - ~5 to 4.6 billion yrs ago
“Hadean%Era”%
In&9me&EARTH’S&interior&accumulated&
heat&
New&atmosphere&created&by&volcanic&
outgassing&and&delivery&of&gases&and&
water&by&ice)covered&comets.&
Early Earth began to heat as the last extraterrestrial collisions subsided 1. Rock is a good insulator – stores heat 2. Collisions produced heat that was stored 3. Radioactivity 4. Gravitational contraction
Earth Developed a Magma Sea 4.5-4.0 billion years ago
What&is&the&physical&consequence&of&mel9ng&a&ball&of&rock&with&&
many&different&types&of&elements&and&compounds?&
Fe/Ni%
Fe/Mg%
Increasing%Fe%toward%
core%
Increasing%Si%toward%surface%
There&are&certain&trends&in&Earths&chemistry.&
The&crust&is&rela9vely&depleted&in&Fe,&Mg&and&enriched&in&Si,&O&
Learning&Objec9ves&–&Chapter&3&
• I&can&interpret&the&role&of&plate&tectonics&in&shaping&the&topography&of&Earths&surface.&
• I&can&apply&my&knowledge&of&plate&tectonics&to&
predict&the&rock&chemistry&of&the&crust.&
• I&can&classify&types&of&plate&boundaries&and&the&processes&occurring&there.&
• I&can&iden9fy&natural&hazards&at&plate&boundaries.&
Main Types of Plate Boundaries
1. Convergent a) Ocean-ocean b) Ocean-continent c) Continent - continent
2. Divergent 3. Transform
Much&of&Earths&topography&reflects&
the&work&of&plate&tectonics&
The&role&of&&
par9al&mel9ng&
Granite&
Basalt&
ParDal%melDng%occurs&when&some&minerals&melt&
while&others&remain&solid&because&their&mel9ng&point&has¬&been&reached&
Convergent%boundary%–%3%types%
Ocean)ocean&convergent&boundary&
Two&oceanic&crust&plates&collide.&Older,&denser&plate&
usually&subducts,&site&of&Island%Arc%forma9on.&
&
Ocean)con9nent&convergent&boundary&
Plate&of&oceanic&crust&collides&with&plate&of&con9nental&crust.&
Oceanic&crust&is&subducted&&(goes&under)&con9nental&plate.&
Typically&an&Ocean)con9nent&boundary&will&precede&a&
ConDnent\conDnent%convergent%%boundary&
Copyright&©&2014&John&Wiley&&&Sons,&Inc.&
All&rights&reserved.&
Divergent%Boundary%Seafloor&spreading&leads&to&the&
forma9on&of&new&crust&that,&
compared&to&con9nental&crust,&is&
rela9vely&enriched&in&iron&and&
magnesium&and&depleted&in&silica&
(SiO2)&(because&it&reflects&the&
chemistry&of&the&mantle).&&
&
As&two&plates&con9nue&to&move&apart,&
the&rock&in&the&seafloor&grows&older&
as&its&distance&from&the&rij&zone&
increases,&and&as&it&ages,&it&cools&and&
becomes&denser&and&is&buried&under&
marine&sediments&that&are&deposited&
on&the&seafloor.&
Paleomagne9sm&confirms&the&seafloor&spreading&
hypothesis&
• Geomagne9c&field&
switches&from&reversed&
polarity&to&normal&
polarity&on&irregular&
basis&
• Iron&crystals&in&magma&
incorporate&Earth’s&new&
magne9c&orienta9on&
• Iron)rich&sediment&
par9cles&align&with&
geomagne9c&field&like&
compass&needles.&&
WHEN%LITHIFIED,%MAGMA%AND%SEDIMENTS%PERMANENTLY%RECORD%ORIENTATION%OF%GEOMAGENTIC%FIELD%AT%THAT%TIME!%
TRANSFORM%BOUNDARY%&
(side)to)side&plate&
movement)&
FAULT%%“a'place'where'the'crust'is'broken'and'the'broken'edges'
are'offset'rela7ve'to'each'other'(either'ver7cally'or'horizontally)”'
! Earthquakes%Tend%to%Occur%at%Plate%Boundaries.%
Plate&Tectonics&
explains&
chains&of&
volcanic&islands&&
Hot&Spots&
%%%%
%%
&
&
&
Lithospheric&Plates&Carry&Con9nents&and&
Oceans.&
Learning&Objec9ves&–&Chapter&4&
• I&can&describe&the&structure&and&behavior&of&an&atom.&
• I&can&explain&the&process&of&crystalliza9on&including&single&and&double&subs9tu9on.&
• I&can&categorize&the&major&rock)forming&
minerals&by&chemistry&and&typical&rock&type.&
• I&can&describe&where&minerals&occur&in&my&
daily&life.&
A&Rock&is&a&solid&aggregate&of&minerals.&
&
&
&
Four&different&minerals&are&obvious&in&this&piece&of&Granite.&
Atoms&are&the&smallest&components&of&nature&
with&the&proper9es&of&a&given&substance.&
%
• Electrons&(nega9ve&charge)&
• Protons&&&(posi9ve&charge)&
• Neutrons&&&(no&charge)&
Atoms&bond&to'achieve'a'stable'electron'configura2on.'Most&atoms&
bond&to&achieve&&8&electrons&in&the&outer&shell&)&the&so)called&
“Octet%Rule”&
Types&of&
Silicate%Structures%
Si2\%O4+%Na+%Ca%2+%Al%3+%Fe%2+%(3+)%Mg%2+%K%+%
Metallic%CaDons%
&&&&&&&&&&&
&&&&&&&&&&&
&&&&&&&&&&&
&&&&&&&&&&&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
&&
&
&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
&&
&
Mg2+%
Fe2+% Single%%SubsDtuDon%
Na+%
Si4+%
Double%SubsDtuDon%
Ca2+%
&&&&&&&&&&&
&&&&&&&&&&&
Al3+%
&&&
&
There%are%seven%common%rock\forming%minerals.&
&
Olivine%%Pyroxene%
Amphibole%
BioDte%
The%Feldspar%Group%
Quartz%
Calcite%
Orthoclase%and%Plagioclase%
Silicates&–&Earths&most&abundant&mineral&group&
Learning&Objec9ves&–&Chapter&5&
• I&can&iden9fy&where&igneous&rocks&form&on&
Earths&surface.&
• I&can&apply&my&knowledge&of&plate&tectonics&to&
predict&the&type&of&igneous&rock&that&will&form&
in&any&loca9on.&
• I&can&classify&types&of&igneous&rocks&in&terms&of&
texture&and&composi9on.&
Igneous&rock)forming&environments&
%%%Felsic %%%%%%%%%%%%%Intermediate %%%%%%%%%%Mafic%%%%%%%%%%%%%Ultramafic%
Intrusive%%%%%%Extrusive%
ComposiDon%
Texture%
The%Igneous%Minerals%
Granite%
Rhyolite% Andesite%
Diorite%
Basalt%
Gabbro%
PeridoDte%
The%Igneous%Rocks%
Igneous&rock&is&a&ubiquitous&component&of&Earth’s&crust&
because&it&evolves&as&a&product&of&tectonic&processes.&
Learning&Objec9ves&–&Chapter&6&
• I&can&describe&&common&magma&types&and&
why&and&where&they&form&
• I&can&predict&the&shape&and&erup9on&style&of&volcanoes&based&on&magma&type&
• I&can&discuss&the&impacts&of&volcanic&erup9ons&
BASALTIC&
&
ANDESITIC%&
&
RHYOLITIC&
Mount%St.%Helens,%1980%
AndesiDc%magma%erupts%explosively%because%it%tends%to%have%high%gas%content.%It%is%viscous%and%therefore%traps%gas,%builds%pressure%and%explosively%erupts.%High%viscosity%is%related%to%high%silica%content&
There&are&three&common&
types&of&magma:&&
Shield&Volcano&
• Low&silica,&low&gas&magma&originates&in&the&mantle.&
• Fluid,&basal9c&lava&results&in&“Aa”&and&“Pahoehoe”.&
• Low&viscosity&creates&broad,&gentle&slopes.&
• Some9mes,&PhreatomagmaDc%erupDons%(rapid&expansion&of&steam)&occur&
when&lava&contacts&water.&
• Eight&main&islands&are&exposed&9ps&of&the&Hawaiian&Ridge.&• &&Age&range&is&modern&to&~6&million&years&old.&
• Volcanoes&develop&on&the&Pacific&Plate&as&it&moves&across&the&Hawaiian&Hotspot.&&
Hawai‘i%
Atoll%formaDon%
FEATURES%OF%STRATOVOLCANOES%(composite%volcanoes)%
• Alterna9ng&
andesi9c&lava&
flows&and&layers&
of&explosively&
ejected&
pyroclas9cs.&&
• Magma&is&
intermediate,&
making&the&lava&
viscous&and&
difficult&to&erupt.&
• Explosive&
erup9ons&due&to&
buildup&of&gases.&
Rhyolite&caldera&complex&
Mid\ocean%Ridges&
develop&at&Spreading%Centers&Basal9c&flow&creates%global&network&of&interconnected&ridges&
submarine%volcanism%
Spreading&Center&Volcanism&
1.#
2.# 3.#
4.#
For#each#loca/on#describe:#magma#type,#volcano#type,#erup/on#style#
Rhyoli9c,&Rhyoli9c&Caldera&Complex,&Explosive&
Basal9c,&Shield&Volcano,&Effusive&
Basal9c,&Shield&Volcano,&Effusive&
Andesi9c,&Stratovolcano,&Explosive&
Plate&Movement&Powers&
the&Rock&Cycle&
