nat sci - minerals
TRANSCRIPT
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. :: .r...,,,-r n r\ ! ! :, *i.l\ tI > ir fd{lut i' ': :
!ti-I1 /!l" i\ r l-
Minerals:l"
1. naturallY occurrtng
2. homogenuous,solid :
3. cornPositicna. chenric':'l (clefinite but.generally not fixed)
b. PtrYsica4, orderecl aiorni.c ?fl'?rrlerl€flts. .trtrrrt f :'rme'l oy ill(lrganic prrrcersses
Mi neral oi rls - natttri:liy occurri n g 4]1ryThgf sr"tbstances
*Tire orderly p.arterns ihat
crystallin u- stru cture
ffq'NERALS
witrtout crYstalline structure
aton:s of elements assume in a rr''ineral is called iis
* Polymorplrs r ntinerals lra"ing the
crystalli;',e struc:t r]'es I
examPles:
same composition/elernents br-rt different
-* Pvt'tqano ir.-arcasite . -;
-- -l -^^^nrla I- Calcite atrd -.-,ragonite .---__ I
*Alias es:1. Caiclte - islan'l sPa;
2. FYrite - 1os1'1i cl'rld
3. Quart;. - ice cnilstals
Georgius t\gr:cola (Georg Bar'rer) D",f.q Metallica- , ..,,,,' ,,, , ,i, ,, . ,
Optical Fic';:e*ies;
2- dotrble refrtl;tion
':---
fff:1":',oJ11J':1,. rrerar oytlrald unngu*rg"3,; consists rr a sroup oi' crvstai
t,,,,"r, Tii';i':*n'.f,-nuuu the same relation to the'"j"ll::::,^oj' ,-th* same chemical an* physical properttes
s':rintlettv ancl cltsPti'
because ;:[l are ui ;.erlain bY
af'ang€'Tlentex. pr,smatic
cubic '
*Nicolas steno - pointed out that the angles between correspo.nding faces on
"rfttuft of a nrine:tai [quartz] are always the same
* Rome de I'Lsle
*Law of consta*cy of Interfacial Angles - angles between equivalent faces of
crystals of the .ru"l* substance, measured at the same temperature are
constant.
2. crystal habit - e.iternal shaPe
ex. botrYoidar, iihrous, grar"uiar
3: color - i': ti:e brightr'.ess or Carl"ness of a mineral :r-,- -^-.-{-r'.._. - resurl of ilie ieflection of light within the visible spe -trum
a. idroch,om:tic - ex. rruscovite (white or c.olorless), azurite (azure blue),
' rnalachite (green): sulfur (yellow)
b'. allochr:matic - ex' quartz
4. streak' is the color qiven by a pulverized mineral
eX'a.hernatite:streak=reddish.brown/indianred| : color = red to black
b lir'ronite : streak = Yq'llow: color = bl''-,wn
5. luster - qual:':, 3nd intensity of right that is reflected frcm I re surface of a
lnir,eral- can be lrouPed into: 'r
a metailic - luster "rf untarnished rnetal; the usual characteristic' of
Iike atoms in the same geom€
I
dark and opaque rnineralsex. nylite, golcl
h. non-metallic - ir,utatl"rizes the colored nrir erals , , l :,
, b. i resit'rous - appearance of resin .
b.; vitrer-rus - glass
u.s ouiil"urt'i:b.4 adamantiire - diamondb.5 silkY - silklikeb.i pearly - iridescent pearl-like lusJer..,
u.z 'grenJv
-rpp"ars to be covered wiil. thin layer of oil
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6. lrarciness - abiliiy of a rninerill to-withstand abrasion or scratching- in .licated in ternrs of the Mohs' Scale of Hardness
q
114-r5 diamond hardest
Practical scale:
r;, specific
ex.:
gravity. - refers to the ratio of the weight of a volumeof material tothe weight of an eclual volume of waier
- spr:ing scale; hefting the mineral by hand
| 2.65 feld 2.56-2.76old
c. boti a and b
19.3
q. cleavage -,i:iers to the characteristic tendency.of mat,minerals tc spiii. c:'
sepa:'ate easily along certain planes- govenred by interrial arrangement_ weak,:lssl
a. .ype of brr cring \b. greater alomic sPacing
rfectvery good at 9C degrees to each other'
fair at 90 dectrees I9,n9-.--.--iat 56.dsgleeg !r 124 degree.- amohibole
e
Perleei-oei-ellA Oegrees; rhombohperfect _ diamond
calcitefluorite
CLr-coin
feldspar
'r nerft':ctv 'F
sphalarite
g. fracture - refers to the nature.of ir''" surr"ce formed by the ''rreaking in the:
oir""i'"n other than those of the cleavage
' -i-\a' cort:hcidal (ex' quartz)
b ri;'i;;;i'itint"'Yc' hai;'liY' d' irregu'ar
- ^r ^r'"^{rrral rnta: ruintiing or-
l0.parting-breakingalongp|anesofstructuralweakness;resultofttpressure
ll.tenacity-resistarcethatamiiteralofferstobreaking'crushing'bendirig'tei ring
a. brittle - breaks or powders eas.ilY ,
n' tnuiiuuble - hammered into thin sheets
c. sectile - can be cut'into thin shavings with a knife
' cl' 'Cttctile - drawn into wire
". ;;ilL - n*nos but does not return to origina' shape
nr
12.
4'I
14.
', 5.
16.
1'l .
f. elastic
fluorescence' artd phosphoresceneet.
magnetism
reaction to HCI
taste
srnell
striations
. CI.ASSIFICATION OF MINERALIE.I-CCORDING TO CHEMICAL GROUPS
native elements old, sulfur, diamondoxides maqnetite, hematitesulfides rite, qalenasulfatescarbonates calcite. dolomite
apatite
EIGHT MOST ABUNDANT ELEMENTSIN THE EARTH'S CRUST
27.72B.135X0
silica Tetrahedron . basic burlding block of the earth's crust
*polyrnerization
Silicates - most abunCant mineral group r
Feldspars - rnost abundant mineral
(bl Silicon.Oxygen Tctraledron cxpandcd
3.632.832.59
hclsphatessilicates uartz, feld l-
(rl Teuahcdron
(d) Top view
Silicate Structures
orthosilcate ornesosilicatesorosilicate
cyclosilicate
irrosilicate
phyllosilicate' (si2o5)-
lectosilicate
'1. quarlz2. feldspars3. nephelilg4. sodalite5. leucite
epidote, hemimorphite
beryl ,
roxenedouble chain SjaOrr amphibole
sheet silicatequartz, feldspar
framework
t
COMMO}{ ROCK-FORMING MI NERALS
6. mica
amphibole9. olivine
(sio4)independent SiOq grou
(Si2Oz)lir.king of 2 SiO4(si6o16):rinq silicateschain silicates
sinqle chain (Si
II
,l'Definitions:
. -*.. cfrnred, r:onsolidatedirlocirs - r1:ltursuv ::il;;i.;;r, glass oroiganic ttiatter, rocx
4.1 lGNDOus R(Juri"u '
t ^r mrnerals'niaterials whiclr maybe conposeo ut
a cornbination of these' l
Iglteorts roclcs:fLatin "ig7lf$" fire) - fgrrned by direct
nlilgttt' Magntu
crystaUiztrtion and solidification of
- "l{llr,acled nrixttrrd'
E l,s gi il ile;tuilssleri$ii- rnol:ih
-'1,:, t*.,?f,
,lTilo",',u*d r:l:?:51 tlissslvecl sases ' : or in rhe upper rnantle due to
' forr:retl n' o "*uti
Jtltrtr partial *ati'ie ii 't'qti'wer cnist or in the upPer rnar
- ' ';;i;;,';'ic iieat,anrl/ot decreasT:.[:Tlfapped lruithrn
the earth's cnrst
-;.;,i;;'l.placecl on tho earth's surla(
-;;,;;n.,,. cltnmbers
*,*;r{:L::::f;j::,t',# l,"f,f'Na' K,'
-r ^:- S(Oi - PnllclPat- <rjssalvecr gases ;;;ii;:;riiu,*",r uirlo*tv and explosive characteristics
- rilnfie ',f t"nt1t"*tit"J' 6i]0'- 1200'C
- ,]"rir, L'I20-,:aPor, COr, SOz
- Xlrvn
Lli.'ir.r-,j:,Pggn. tltsnltic Inagmfl
l"t. Grnnitic nraEitna
" 50% Si0z. 't:900-12C0"C
highlY fluid
eolr6Y, sloa
' T: lower than B00oC
- highlY viscous
l.Ld.tiri,--nn{erysldliag'lstr . -c^L^ni:'.i.aciion $eries = '-o;j-"'tiy series of change"
J- ' ,1".',-tts Reactiorr Series .,i. ,
.," r in whish the'earlier fornred inrler$s
:; n ll; t' -*:i'iil1: :, : Tf i;' :'il:r:'; il; ';;'i #'oi;"' r'm "''t i' trre
, tt,rti.*. in the mineral
is graduallY
rnrgma'fbr
ex.: plagioclase (Ca-rich torl(rich)f.)iscontinuous Reaction Series : reactiorr in which an early crystallized mineral reacts
with the remaining licluid which constantly. changes its conrposition during cooling to form
ancther mineral
ex.. 'ii,,,, Enstatite + Forsterite + Melt
2 Mg SiOr MgzSiOa SiOz
Magmatic ;lifferentiation : a general piocess in which the original magma with its full
.ung. of cornponent elements is separated into rocks of different mineral composition
a. fractionation
b, filter o:essing. c. assimilation of the wall rock
d. magnra-mixing
Morlqresl-af.tnsglqaa. external.forces - sqrteezing of rnagma chamber and causs filter pressing
b. internal forees - gur **punsion; stoping (magma move along fractures until they engulf
the ho$ rock)
tgnerrus rocks ,
- 80% of the mass of the earth's crust
- Genetically classified intorr''| a. plutonio: intrusivb
li, volcanie = extrusive Ic. liypabyssal
- Mineralo$ically:a, felsic - large proportions of K-feldspar and Na-plagiocl456 + quartz
b. mafic - Ca-plagioclase, large hmounts of{endrnagnesian mlrerals but littlequartz or K-feldspar
c. ultramafic - composed entirely offerromagnesiatt rninerals with minor amounts
- Major textures of feldsPars
Textirre Dcscription Inte'rpretationPhaneritic grains visible to the
naked eve
relatively slow cooling
Aphanitic grains not visible tothe naked eye _ _
relatively fast cooling
Forphyritic some grans coarse,
others line(phenocryst,
sioundmass/matrix)
two cooling rates
no minerals fonledr id s"tft; co4llg witElgSie eg
9X
Most Abundant lgneous Rocks
s.trapes brrfiirtiilve rock bcdies
" Flutoir ='any llass of intntsive rrrck regardless of its size or shape
a. batholithsb. :tcsksc, dikesd. sillse. lacolithf. tupolith
imflb rlancb:' r.retaliic and
' ' : -"L. :- i' (' '
\ro!r:n:iowith the
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non-metallic minerals (mining): gold district
5.1 Yolungoes ''
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: a vdni which connects a reservciir of maguu in the deptlis of tlie earlh's crust
surface of the earth: ejc"ts lava, fragmentaVpyrociastic rocks and gases
: cons (volcanic edifice)
A. Lavanffiu that h1S reached the surface of the earth
- different compositions ancl temperatures iesulted into lavas with a rango of physical
properry (i.e., r'iscosity) and fcafules.
a.. paloeho* riua -:t:glly fluid, T = 1000"c; thin; smooth, biilciwy, ropy suilace
b. aa l.vr - fi'-il; "ibtlu$;
iini.'guq $low moving; seu*rh neters thick;rough'
':' jugg*d, sPinose
c. pittorv-,ta.iu1"-Iffii;pted under water or ice; (toothpaste-like) '
#-
Extrusivefeiric r" ck[ K.ftiltdMptfiioclase, qtr arte, less
amountp of biotite or ampbibqle-. -. .
ffie(30-50% anorthite),
a,rnphibole,, gqoi*. (quartz may be present in
Intrusive
Granite Rhyolite
Diorite'Andesite
amounts of olivine"t'Gali,bro- ' Basalt
I .f
a ,l ll. F!'rqginstic materials
-:il:,:m#*'ffffiT$rrue**,s blown-out from a volcanic vent under pressure or
raoidlv expanding gases present in the magma
- rr*tpoi.d eitfiei+n in solid or plsstic state
- classification in telTns of sizes and shapes of the fragments r -a, blocks - > 64 mm; pieces of crustal layers or older lavas
b. bombs - > i4mm; spindle/spherical masses from the congealing of blebs tllj:d
Iava
" b"l bowdung
' i b'z breadcrustb'3 armored
,0 c. lapilli -2-64 mrn; saccretionary lapilli
4 ash-<2mm
+*r- Pu,nice, scori&, obsidian (volcanic glass)
..'j:a
T:
.;, ..:,ts, domppsite/strntevolcnnoes: altemntingla-yers of pyroclastic rocks and lava
ex.. Mt. ttu.ii, V.r,,nius, Stromboli' Etnq Mayon' Mont Pelpt'Krakatau
' nuee srdente (glowine cloud) : a higtrly hh?{ gas 'charged with incandescent
i ,rt porti"ie, ,oitrut i, i"g"*ii*r u *ouile ernulsio--n ydtidense enough to maintain
lntact with surface '
r.ldera - co.llapsed volcano (ex' Taaf,Laguna Bay)
.;r .:ir
b. Shield ".olcailoes - broad, gently sloping.v-;rcantjes comPo$ed of solidified lava flows;
rarelY stePPer than,f:dtigrees '
ex. Mauna Loa': '
, a
'il. Cindur cones - volcano that is constructed of loose fragmentilpyroclastics;slopes
about 30-33 degrees
ex. Parictrtin
- PACTF'IC RING.OF FIRE/CIRCIJM-PACTTTC BELT
Type of Volcanic Eruptions: -rr --^,.-|.^.rri.onh,erl .,cq.eq*. influencealfnir"ority of the magma aitd a{nourlf oi dissolved gases
- .\iolencs" "'r.n
,*pii* i, ,rtuit io ,rr" o*gree of fragmentation and the \
distance
a. Fflaw*iian - ubundant outpouring of lava flows; lava fountains; quiet liberation of gases
b. Stnoxnholinn - milil, explosive eruption of pasty, incandescent bombs and scoria
ql, accompanied by a white vapor cloud; discrete explosions
- c. vutrcaninn - btsw-out of solidified cnrsts (over the crater); acbompanied by a great-
;;;iifl.wei shaped eruption cloud containing an abundanco of ash; lava'flows may
issue
d. Flininn - eruption of extrerne violence; gas-blast eruption; eruption cloud resembles an
Italian stone pinetree (shooting upward of the column then spreading out); huge'
sustained eruPtion column
Felean - extreme explosiveness; nuee ardente
Phneatic'
F.trreatomagmntic l
Uliru-Ptiniatr - excessive emission of ash resulting to negative landformslLE
g
h.
n*Vqlpgnlg-Hazards (
a. ieplua fallb. pyroclastic fhll
lrnportnnt: geothermal energY
c. lava flowsd. lahars
(ex. Makban, Bacman, Tiwi)
e.
f.caldera collapse
tsunami
s[rMM3'nY
lava fottntains
ffiffi
.. j,::,r. i.:r:.il..l_,'1
:,t,il,i
i+:ir:ri,'i.i;i
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iiii-ig' btj;iElni.i.'i1.1 Z .E Y
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::: olii:i .E r,
l:..ir. 'itr.'..:+i
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o=do)
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LY:t
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wil,AT'r{rcntruc nivn ER,osnoN
iVE,:X'I.!!Eit,lNi- is the physical disintegtation arfci r,hernical decontposition by ivhich
rocks iire changed upon exposure to "agents" at or near the earth's surface, with little orno lranspo;t of loosened or altercd Inateriai
*- agents - hydrosllhere, a-tmosphere, biospher-e
.4. l\4cch*nical Weathering - is the breakdown. of rccks into smaller fiagnents by
vat'ious ph1151"'1 stresses
- ::tictly a lthysicul pl'oces:; willxnt a change in chemicalc1tilP)r'iliott
fr4 erhilnicaN Weath ering Frocesscs
a. ice wedging/ttost wedgingb. salt crystal gror,vth
L:. slrceting/unloading - releasc of confining p:ressure
exfoliation - fonnation of cprved sheets of rock by release of pressure
d. anirnals and plants
e. tlrermal expansion and contraction - seasonal/daiiy temperature changes
tr]. Chenrical Wcattering'- is the process"by rvhich chenrical reactions transform rocks
and nrinerals into ne;, shemicat cornbinations that are stable under conditions prevaillng at
or near the earth"s sur{-ace
lioie: more ef-fectittc itt x'armer clintcle:i - lrcat increase,s tlw xtte of ma:;t
reucf irnts
Chcnricnl Wcatherinq Proccsses
a. Flydrolysis - H' or Otf of the water anAffinUe ions of the rninerals
Ex. I(-ibldspar
2l(Alsi?o8 + 2tt2co3 -F 9FI20
Ortlroclase Carbonic Acid Water
Al2iii205(ot-t),r -l- 4l-I4sio4 J- ?tc + 2{-ICo3'Kaolinite Silicic Acid Potassium Ion Bicarbondte l.on
{, :--*ffi
l). ulSSOllltl0n - Fr2U
Ex.b.l NaClb.2 FITO
CaCOr
. ,1;'
-- --Llnlversat solvent
T
T
HzO -,----+
Na -F
COz HzCOrFizCOr ------+ Caun F
1- FLO
2HCO:-
c. Oxidation *
Ex.2FeSz
4Fe'*
is the cornbiration of oxygen ioris ivith cations
gl&qlar dalrygolbstlqg or "onion-skin weathering" -- produces
relat ively untveathertd material
4SOt' + 4F-t+
2H?O
spheroidal boulders
X{.esults/f roducts:a. regolirlr - fragincntal and uncor.rsoiidated rocl< material that has coarse grains
rvith angular edges and a composition sinrilar to the unweathered rock
" b. very large increase in the surface area of the v/eathered rnatedal, f,,. soluble rnaterials
Xlilr:tons afT'ccting the nntes o{' weathering:
I. susceplibility ot'the consl-ituertt roirrurals to rveatltering
- Goldich Stability Series-- nrinerals forrned at liigher temperatures and pressures tend to be less stable in
uveathering environment than those formed at lower temperatures
2. climale or intensity of the weathering processes
-- total amount of precipitation
- intensity ol'rain-- sr:asonal variations-- infiltration -r
-- run-ofl'and rate of evaporation-- teulperature
''r'wnnn, hunrirlclimate Vs. coid clirnaLe
-J. amount ol'srrrface exposecl to the atmosphefe
f,i?0$'/Ory - forcehrl physical removal of material frorn ihe parent rock, alwa.gs
acconrparried by transportat.ion and eventually end in deposition
CI
+ 7O:r +-t- oz {-
zHzO F 2Fe'-' +4# -_| 4FErr'r +
of
a. running vraterb. grouncl waterc. glaciers
d. 'ivind€.'waves' ald currents
f- mass wasting:' :
g. oigarric activi\'
'" n Dcpositio n itrtti [ix.hit'icatiorl :
I
Il--
Lithifliq:ation - is the term for p group
sedirlen.rarr/ rocksof processes tlrat conrreft loose sediments into
u. C1:me6talion - the process by which sediments are convefted ilt<i roclr by the
cliemical precipiiation of rnineral material / cqment among the grains of the
sediment I
+
t{t-, .
silic.r, carbonates and irolt oxides
Ccrnpactittn = is tlie loss in over-allvolunie and pore space as sedinrent
particles are packed closer together by the weiglt of, overlying rnaterial
Cry:;tallization - refers to crystal developmelit and growth by precipitation
fi'om solution; no cement; grains are held together by inierloclcing crystals
Ser{inrept:ltion - tlre process of fornring sedinqnt in layers, including ttre separation
rocli partioles fit'lnr the palerrt Inaterial, transportation of these pa.rticles to the site
deposirir:n, actual cleposition/setiiing, litlrification and consolidaticn into rock,
oio.l
'\.
SEDIMEhITARY ROCKS
SedimentarY Rocks:
- Latin woi-d, sedimentum = "settling"
- formed from consolidation of materialsprecipitation and from secretion of organisms'
Sediments - finely divided matter consisting of mineral grains and organic
matter derived from pre-existing rocks and from life processes,.transported by
and deposited from alr, water or ice'
- origin:
(1) weathering and erosion of pre-existing rocks
izi cnemical prebipitation from solution(3) secretion of organisms
Ocean = ultimate destination
Partlcie size classification for sediments
Two Maior Textures of Sedimentary Rocks.
1. clastic [Greek k/asfos, "broken"] = discrete fragments and particles
2. non-clastic texture = minerals forming an interlocking crystal pattern' '
from pre-existing rocks, from
.
CommonSedimenf Narne
Gravelor
Rubble
[dden-WentworthSize Glass .
Particle Name
1116-21/256-1/16
Iypes of Sedlrrient'ary Kocr(s
a. Detrital sedimentary rocks'.particle size is the primary basis
Detrital RockUOOenlWentworth
Size Class(Particle Namq)-
CommonSediment
NameConglomerate
UI
Breccia
Boulder Gravel
RubbleCobblePebbleGranule
SandstoneSand Sand
sitt Mud siltstone Shale or mUdstone
Clay clavstone
b. chemical sedimentary rocks: formed by direct precipitation of minerals
from solution.
*Precipitation occurs in two.ways:
(1)lnorganicprocessessuchasevaporationandchemica|actirTity can produce chemical sediments'
- iximprei: dripstone and halite (salt)
(2) Organic processes of water-dwelling organisms form
biochemical sediments
Rock NameGroup Texture Composltton
Limestone
lnorganic
Clastic or non-clastic
calclte, u?uu3
Dolomite,CaMq(COs)z
Dolomite (Dolostone)Non-clastic
Non-clastic MicrocrYstallinequartz, SiOz
Chert
Rock saltNon-clastic Halite,NaCl
Non-clastic Gypoum,CaSOo'2HzO
RocK gYPsum
Calciie, CaCOg Limestone
OrganicClastic or non-clastic
ChertNon-clastic
Torc6sttc
MicrocrYstallineouartz, SiOzAltered Plantremains
Coal
-..
SedimentarY $tnuctu res
*provide additional information with regard to the depositional environment'
':rmed as bedding or stratificationl1, l-aYering [also t(
:l1.1 strataor bed: thickness of tftu layer is 1 cm or more
l.2taminafion:thicknessofthelayerislessthanlcm
*may result from differences,Qetween |ayers in texture (e.g., change in
grain sizei'ti*iui tomposition' color or cementation'
-beddingptanes.=flatsurfaces.alongwhichrockstendtoseparate
e end of one episode of sedimentation and the beginning of
another
(b)pauseindepositioncanleadtothecreationofbeddingplanes
2'Ripp|emarks.=smatlridgesofsandformedbymovingwindorwater
2,lCurrentripp|emardE:lfairorwaterismovingessentiallyinonedirection
2.2oscillatoryripplemarks:Resu|tfromtheback-and-forthmovementofsurface*.u"'inshal|owwaterenvironments
3'Cross.beddingisanarrangementofsmallbedsatanangletothemainsedimentarY laYering
by a Progressive4. Graded beddingdecrease in grain size
5'Mudcracksarepolygonul",.u.k,thatformwhenmudshrinksasiidries'
is a tYPe of bedding characterized
upwaid through the bed'
fiNETAMOffiFffiC RCCKS
Metarnorphic rocks = rocks resutting from changes in temperature andpressLtr'e ancl frotr changes in the chemistry of tlreir poi'e fluids.
= can be formed from igneous, sedimentary, orprevior-rsly nretanrorphosed rockb.
= solid-state .reaction= consist of a fabric of irrterlocl<ing crystal grains,
usually with preferred grain orientation.
*Changes -,,.t.* new minerals, textures and structures-')\
occur in the solid rock; witltout melting of rock
I. Principal agents of metamonphisrn
a. lentperature- rarely below 200oC, upper limit is ihe melting'temperature of
tlte tock
b. Pressurcli b.1 confiping/static = pressLr-e applied equrally on all surface of tlre
BT5r"r, ecl/dynamic - pressLrre applied unequally on the surfaceof a body
b.2.1 compressive - flattens objects perpendicular to appliedpfessLl[e
b.2.2 shearing flattens objects parallel to tlre applied
pressLlre
*Fcrliation - parallel arrangement of textural or structrrral featuresin apy type of rock; planar structure that results from flattening of
tlre constituent grains of a metamorphic rock'
c. Chentically active/migrating f/uids- loss and gain of ions and atoms- snrall arnir-rnt of pore fluid provides an inrportant medir-rrn of
transPotl
'Mletasornatisln
introduction of ions fronr an external
generally connected with magmatic
source
intrusions
I'r
T-- \l,/ilil
new material (front magma) + pore fluid = new mineralstable in the new chemical environment
l[. Types of metamorphlstm
a. Contact/thenmal metarnorphisrn = metamorphism resulting fromthe intrusion of lrot magma into cooler rocks.
*dorninant factor: temperatu re
fvlelarrorphitr
Qracle.
Ll. Regional metamorphism = metamorphism caused by relativelyhigh ternperature and both directed and confining pressure
= *affects broad regions of the Earth'scrrrst, usually in areas of tectonic activity. '
= foliation*heat: great depths, earth movements, batholiths"pressure: burial, tectonism
, | .t t,. -,:. .
c. l-lyclrothenmal nnetamorphlsm = metamorphism cauSed by
migratingftLridsandbyionsdissolvedinthehotfluids.lll. Textures of dretamorphic rocks .,,. .' .,
a. slaty = nearly perfect, planar, parallel fotiation of very fine glainedlplaty (flat) minerals (i.e , rnicas); low-grade tnetamorphism
,, l,l.t
, .li,..1,.,.....:,,.
b. Regional meta*orphi"* = metimorphiir .uru-d bg relatiu.lg high
ternperatrr. "nd
both directed unJ .ot fining Pressure= u{Qd..ts brood regions of th. Earth's
crLrst, urrullg itr areas of tectonie activity
= foliution
. ::::;:::1i : f i:i::': J *'m e n'fs1 ba'lh' h'lh s
c.. Hgdroth**uf meLamorphism = metarhotphitm .uut.d by nigrating
fl,ri,Js .und
bg ions dissoln.d in the hot fluids"
111. fct:turo of mctamorphic rocks
(..
a. slatg = nearlg pe#ect, planat-, purull.lfoliution of v.tg fine-grained
plu'y (flat) minerals (i.e., micas); low-grade metamotphi"t
phglliti. = s parallel (but wavg or wrinLled) foliatio n o[ [in"-g,ained
(ol.uu;onulig ,n.diur -g,uii.d) platg minerals (i..., misas and
chlorires), .ih,biting a silkg or me13llic lu*er; relativelg lo*-grad"
metamorphittt'
,.l",,rtose = purull"l to "ub-purallel
foliation of m.dium- to coarse-
qrained plutg ninerals (micas and nhlorite); intermediate-.to h'gh-
e."d* rnetamorphitt
gnei-ssrc = p^r"ll"l to uub-purull-l folirtio. of t.dium to coarse-
,:-.,ri,r"d platrl minerals in' alternating l.g"ru_ of difFerent
cc,mposition; jirter*-ditt"- tohigh-grade metatotphiut \ '
g rnoblustic = -rniform g;ain size o{ equant or- l.andomlg oriented
s:rains
:
l
t l ( | l. | |'-' r,l -'-'1--L-
l' I
t horntelsrc = tine-gained rocks with grains tendlngto be lntergrown
irr rarrdorn orientation
M. C.lassi$ication
A. tlnioliatud with qranular texture
b. rcliiated
oCataclastic roclcs= r.o.ks that htu. b."n granulated by .tuthing-
+ Mqlonite= uataclastic roclcs with floy textures-
Namc Texture Parcnt Rock
ate Slaty Tufl-, shale
P Slatg (silkg sheen);
phylliti.
Tuff, shale
,5chistose basalt, gabbro, tuf{-, andesite,
shal., rhgolit.
Gnciss Gneissose - Granite, rhale, diorite, ihgolite
*l
Deformationancllor shaPe
DIASTRC}PHISTJI / ROCK DEFORMATION
= a general term that refers to all, changes in r.'olume
of a rock bociY
= tfr" strain yielding of a solid to applieci stress ,
*Stress = the amount of force acting on. a rock unit to change its
shape and/or volttme
a. confining Pressure - equal
b. differential or dii'ecied. b.1 compressional - shorten a rock body
b.2 tensional - elongate or purll apart the rock
bodY
b.3 shear - sliPPage
*strain = is tlire.change in shape andior volume of a rock unit
caused bY stress
Iypes of deformation (strain):
a elastic deformation = object returns to iis original size and
shaPe when stress is removed
b. plastic.deformation =.a permanent change in the original
Lr,up* o.f a solid that occurs without fracture '
c. ruPturei , , '.'
Rocks that defcrm plastically by foldin$ and flowing are said to be
;;;;i;".' On'tf.'* otr'*r nanditoikt tested undqr surface conditlohs
],r""..t"i* -[Ji."irv, uri olce they exceed their elastic limit,
*"rt:b*hau* like a'brittle sblid and fractr:re- This type oi
l"t"i*"ti;; i. "orr*o
brittie failure'
--nlinelalswithstronginternalmclecularbonds;=brittle-- weaker bonds = ductile
-- qLrartzite, granite, gneiss = brittle
-- rock satt, [ypsum'-Marble and shale = ductile
L:. time
-- quicKtY = fracture
confining Rressure')
temperature /
Fqs+src '*f{e,o*rv,g -{Sa'bdhaviot of roo{rsl
a. inherent ProPerties mineralogy, gtain size, porosity etc'
high = plastic
,i,
e. solution - loulers rock strength
MAPPING GEOLCIGlc sTRUqliuRES
d
Outcrops - sites where bedrock are exposed
Attitude - refers to the 3D orientation of some geological feature
ex. bed, fracture
strike - direction of the line formed by the intersection of an
imaginary horizontal plane and any planar feature
- trend o ,
Dip.istheangleofinclinationofthesurfaceoftheplanarfeature **ur,-,r6d from the horizontal plane'
'4tt
FOLDS
Folc.ls - sinrply a bend or waverike undulations in bedding, foliation,ciea,;ace rir other planar featlrres
Parts of a fold:
, a. litnbs ar ilanks - twcr sides of a fold
b. hinge - line of maximum curvature in a folded bed
c. axr's - line paratlel to the hinge; line moving parallel to itselfthat generates the fold
d. axial plane - imaginary surface that divides a folci assymmetrically as possible
e. plunge- angle between the fold axis and the hor-izontal
Types of folds:
i.l. anticline = "arch"; convex upward
b. syncline. = arches downwarcl
d. synrmetrical = limbs clivergle atthe same angle
e. a$ymrnetrical
- overturned = one limb is iilted beyond the ver-ticalrecumbent = axial plane is horizontal
f. plunginE = iolcl with Cipping axis
g. monoclines = broaci flexures; one limb
h. domes and basiri
tt..,,
FRAC'TU RES
A" Joints = are fractures arong which no appreciabredisplacement has occurred
= may harre almost any orientaticn _ verticar,h o ri zo n ta',:::t
;"#:,Xifl '1.,=
Causes:
a. columnar joints form when igneous rocks cool and developshrinkage fractures
ex. Devil's Causeway in lrelandDevil's Tower in Wyoming
L-r. sheeting
c. rocks in outermost crust are cieforrneci
n" ,Joints may be significant from an economic standpoint*" ,Joints also present a risk to the construction of.engineeringprojects
B. Fadlts = are fractures in the Earth's crust along which slippageor displacement has occurred.
Fault terminology:
1. hanging wall = the rock above an inclined fault
2. footwall = the rock beneath an inclined fauli
Types of faults:
a. Dip slip fauits
a.'i normar/gravity faurts = extension; the hanging wail hasmoved down relative to ihe footwall '-"''7"'r 'uq'r rrq
6 graben (German word, "grave,;1 = wedge_shaped block ofrock dropped downward
' ll,H:;::"tnt of rock that have moved upward relative to
a.z reverse faurt = compr"rrion; hanging wail has moved up', relaiive to the footwall; high_angledi
I a.3 thrust fault = gompression; _hanging wall has moved up, relative to ihe footwail,; row-angred 1so" oi +6"i'-',
b- strike-slip faurts = raterar faurts; high-angre faurts in which thedisplacement is ho.rizontal, parallel to the stit<e of the fault plane,with little or no vertical movement.
b.1 right lateral stike-slip faulUdextral
b.2 left lateral strike-slip faulUsinisiral
c. Oblique slip faults
EARTHQUAKES AND REL
trernbling cf the earthEarthquake 'sudden motion or
- vibration in the earfh "ur.u-d
by ihe rapicl release of energy
*Most often are caused by slippage along faulis
Elastic Rebound TheorY:
oFl.f:. Reid, Johns Hopskins University
- slour deformation of the crust (creep) until strength of rock is
exceeded. Then, ruptttre cccurs' Start over'
- 1906 San Francisco Earthquake adhquake,
a. in the 50 y"u" before the 1906 san francisco e
surveys takln in the area recorcled an offset by creep over 3
, il:l"Ji,*nt during the 1906 eafthquake was 6 m, this movement
took plaiu in +O ieconds as opposed to 50 years
Focus - the poirrt at which vibrations of an earthquake originate
Epicenter-pointonsurfac*ot"",-tr.'irnmediatelyabo'vefocus
Rupturesurface-areaonafaultplanethatexperiencesmovementcluring an earlhquake event
^^,r atqcri, vels through rock, produced$eismic Waves .- any elastic waves that tra
by an earthquake or exPlosion
Whenanearthquakeoccuts,seismicWavesaregivenoff.Thisissimiiar to throwing a stone tntol quiet body of water' Wives are created
which move out fiom the point of impact
; and as it movesEnergy is being propagated along these paths
some of the energy is lost'
The farther the wave travels the lower its energY'
Seismograph - iirstrurnent that records seisrnic wav.es
Seismogram - record made by the seisnrograph
Types of seismic waves:
. 'i- Body waves - radiate outward from the focus in concentric spheresand travel through the Earth's intericr
a. P-waves - Primary waves, Longitudinal waves, CompressionWAVCS
- involves alternating compression and expansion of thematerial through which it passes
- similar to sound waves, like ihe nrotion of a spring or slinky, apush-pull rnotion
- movement of rock particles is parallel to the direction of wavepropagation
- fastest waves, travel 5 to 15 km/s- may pass through any kind of solids, liquids, or ga.ses
b. S-waves - Secondary waves, Shear waves, Transverse waves- inVolves oscillation of rock particles perpendicular to the
directionof propagation
- like sending a "wave' through a rope- slower than p-waves, 4-7 km/s- may pass through solids onlY
2. $urface waves - Long waves, L-waves- radiate outward from the epicenter and travel along the outer part
of the earth; generally slower than body waves- greater amplitude and longer period- cause the greatest destruction
a. Rayleigh vJaves - rock particles move in a vertical rolling(orbital) motion, something'like ocean waves
b. Love waves - rock particles move side to side in a horizontalplane
- very destructive and travel faster than Rayleigh waves
Pvelocit.v' } Syeto city > Lvelocity
Locatine an earthqrrake
- in orCer to locate an earthquake, at least three seismograph stationsare needed
- if only one station: distance to epicenter, along a radius from station- if two stations: two possible epicenter .
- three stations: unique point
Measurement of Earthquake Strenqth
a. lntensity - an indication of the destructive effects of an eartlrquake ata particular place
- affected by: distance to tire epicenter, total amount of energyreleased and nature of surface materials
- Mercalli scale (lflodified Mercalli Intensity Index)o qualitative and subjectiveo measure of damage and 'felt' intensityo determined by site'examination and interviews
b. Magnitude - total arnount of energy released during an earthquake- based on direct measLlrements of the size (amplitude) of seismicWAVES
- total ener$y reieased - calculated fi'om the amplitr-rde of the wavesand the distance from the epicenter
- Richter scaleo quantitativeo open ended, <1 to infinityo logarithmic (a magnitude 2 is 10 times more powerful than a
magnitude 1)
Effgcts of earthquakes1^ ground shaking and rupture2. landslides3. iiquefaction
4. tsunamis (seismic sea waves)
o originate when water is verticaily clisplaced during:earthquakes
' uncjersea landslides (turbidite fiows)undersea,rolcanic eruptions (e, g Krakatoa, 1683)
u6'F{ r rc\f Eo. rr, r- ,,'*rF I - lr r*a- t@ds. 4te4+_gAgrfih€4r&rmCoC,ffin tfic gm&rs sititace,charrging their positicns relaiive to one another
* ocean floor remains stationary as ihe contirrents ptowe( thror_rgh it
-- t'lot nev/:a. Buffon - sirnilarity in fossils
b. Snider-Pelligrini - similarity in coasilines*"l'lorth Arnerica and Europe
--'Alfred Wegener - Father of Continental Dr-iftcontinents had been united into a vast superccntinent calledPangaea (Pangea)
; a. Laurasia (northern) _ North America, Eurasia
i b. Gondwana (southern) - lndia and the rest of the continents
ii - driving mechanism: rotational and tidal forces
i -- Wegener's lines of evidence:'l
i a. ligsaw puzzle fit of the continents
,i b. distribution of fossil plants and animals
i examotes:
i b ] G/cs opteris sp. and Gangamopfe4rs sp.
, b.2 Lystrosaurus.sp. - found in Antartica, Inclia anc.l
I South America; land dwelleri (Why not North Arnerica? Distribution of fauna is
"r:::5X,.,,:uJ;:':'3 : )u,n
Arr e ri ca and s o u tir Arrica,i aquatic reptile:.li c. continuity of geotogic structures
- lndia, Africa, South America, Australia and Antartica . tillites'.
' j fossils
)l, i - identical patterns oi'scratches and grooves fornred in the,. rocks
I d. nt*terhs trf pateoclfn"atgs ard qlc"tehby,, rn +he Soratho-rn l-te.rrrsphere
,'1 ' - pr*,.r*I. ; r.,[.-*o, -+"r*otrt";
rn ftr*artica ,;;;;;;-'", once near tfie aqua*or
' .i.iFters v:. *i:rers - (tqao) cpiii-.aa< due rnainry io -rhe onc,r.0.,:t,ur,.,
ltlrrf
t' l
o in oPen ocearl: ^^^ , -,,^-a tlr?V travei uP to 700-800 km/hr
" wavelength >100-200 knt
r wave height <1 m)hing a coastlineo approacnlng d :"i:-'l:'^*^^^-r wavelengih decreases
. h;;;iintruu*", to compensate for low velocity (up to
30m) : '
' velocitY is reduced to < 60 km/hr
5. seiches (oscillating waves on surface of lakes' bays' rivers etc')
6. fire7. t"gionalbhanges in iand elevaiion
.Seismichazardmaps'hqyearthquaKeriskinaparticulararea.-indicateprobabilityofanevent,andprobabi|ityofacertainamount of ground shaking
- Short term Prediction
}some=u""",'byJapaneseandChinesebyuslng|u|eslother data
F factors considered useful: 3
'/ o"toimation of ground surface:";il;i**i tune connecst two .water-fill:: "::tuinersD gravimeters - measures changes in -.-graviiational
strength brought ab,out ,nV liting or falling land; of
;;iles in deisitY of rrnderlYing rock
' cf€e PrTleter u ' :-.. proton precession magnetometer - detects changes tn
[t"'* "u'ift's
magnetic fielcj
" lasers/ sesismic gaPs along faults r, -..'/ puiiurn= ind frequJn"y of earthquakes : :-,:1.'
",',' ,':,'.,,'.'',''',ir-..;':",-'
'/ uno*uf"tts animalbehavio l.. ,,
", :x1"#:3?".#Tl,o*r ,."=irliyily. . ,-----,-^li..a,^ n*i' 16 '-,-{CI. ,/, changes in wateri#;iltb'Jity' t**pe.rature in deep *ullt ',,ti,
.,,i.,,.tt,
, r .,,..
)> rocks contain minute amounts of magnetic minerals that align with the
earth's magnetic field
}.directionofalignmentandinclinationfromthehorizonta|indicatestheposition of the magneiic Pol"
within the rocks
the time and place the rocks formed
n studies show that poles were in.different positions relative to a continent
at various times in the geologic past
t "-o'",1it';:,'", had moved
(2) continents had moved
- continents stationary, poles had moved: paleomaqnetibally determinedpole positions for a particular time should be the same or all
continents
- continents had moved, poles stationary: pole positions slrould differ
among the continents
SEA FLOOR READIF,IG
-- Hess,oroposed that the sea-floor mighi,:l
fYlr)i/rn^I I rv v il ty
crest of the MOR doivn the flanksto disappear finally'by plunging
,- spreading'center = ridge crest- subduction = sliding of the sea
- Driving force of sea floor spreading:
neath a continent
a. Hess: SFS was clriven by ntle convection+ Meinesz and'Holmes hy earth's internal heat
r beneath the crest,
b' uplift of the spreading,ridge j jlstuoiunt formed simpry permits sridingv'rithout the help of conveltion curid:itll:
c' subductecJ slab is rnore dense b;g.urr" it is coid -;
tends to pullthe slab along as it dives .ri;i:ii,ii
Objections. : "
a. viscosity of the magma il ,
b. rocks are very weak under tensi.bn
iiliEvidence for SFS: iii ',
1' thickening of the sedimentary r3x,"r away from the ridgeItl
2 the age of the sediment restiilgi on the ocean floor increases awayfronr the ririge .:ii-,l'1..3.stripesofmagneticanomati"s,.i.:i,
" normar earth fierd - a!_ditir13,and str'ng magnetic intensity" reverse _ subtracts from tfleipr*="ni-ragnetic intensity.leaving elow vatue :ii . '
:'i:r '.:
eAding (1eo8)- "".1':;lT,$JLi.',-nit'ffi';iol;uu; reatures or the ocean r'1or
plus o'tit'nttt; ;i '' ea4hhuakes; mountain ranges'
volcanoes, etc illlil:l;l I i
Plate = large, mobile slab of rocf t{{Xt is part of the earth's surfacei:l1l i i
= large, mobile slab of rocf ii{dt is part of the earth's surface
: entirely "t idl#;oceanic crust' the continental
crust or both ifli\
= assumed to be rigid - t*o'$[drus on the same plate are not
- -r:^^ .^la*irro th each Othgnl
p uqrr. rrcrotrtigs rHEOnv
ilii
l'
: entirely "t idi& oceanic crust' the continental
in motion relative tb each othe;fii
iiiin/linot Plates:Major plates: il;,'--
,,.it.: li r. Southeast Asian-
1. American ,rli z. Nur"u2. Eurasian :ii' 3. CarriC"an3. African ::'
i. inJiun-Arlstralian ''ii 4' Arabta
5. pacific Lrqr'6'
ti ,5 Philippine
6. A.ntartic "l..^, iirr
L.iihosphere = earth's rigid outer shetli!
Astenosphere = Low Velocity Zonei rlue to an incre
=azonetrratnerr.au*$.pr"='icaltyduetoanincreasein Pressure and terRberature
= acts as a runritliilS iuv"t allowing the plates to
.lmove I 'ii
distinit unit' all maior interactions
between p\ates'occur along plate b 'oundariesI " t,:i ' - ^!: 'r" -rnd mountain building*
seismic activitY' volcanlsm a ,!i:'
a' divergent nouhdaiiS:- : where plates ff'.v,:
upu*,i"=iift'*g tt tllupyvellin$ of maierial from n
t; create new sea floor:r'
:,
b. conver-gent beundai-ies = wnere
together, causing orte of the slabs of the
be consumed into tHe mantle as it
. plates Inoveliihosphere todescends an
;r 11..,
A. Divergent Boundaries 'iii: :
a. oceanic divergence - mif,1ked by the crest of the MOR
and basaltic voicanoes :i'ii:
ex. Boun'dary behrueerili\azca and Pacific plates
'1,
b. continental divergence * niarked by rift valleys
ex. East African rift vallqys' Red Sea'
.t,:
B. Convergent boundaries :''
a. oceanic-oceanic' .onuBrg"n.* : ?, 9::alit plates
converge, one plaie subducts under the other
Features:
tVr:fe.
overriding plate
c. transform biundaries = whet'e plates slide
past eactr other creating or destroying lithospherei
::.
.;i.
a.1 Wadati-Benioff zones of earthquakesa.2 volcanoes I.
a.3 island arcs (Philippines, Japan, Tonga, Mariana)
a.4 inner wall of the"trench consists of a subduction
complex and fore-arc basin
Marianas type; fensioiip/ environment,' sfeep-ang/ed
st.rbducfiorr ',
oceanic-continental cohvergence - plate capped . by
oceanic crust is subducutecl under the continental piate
t:
b.1 subduciion complex,'fore-arc-basin, back-arc basin
b.2 edges of the continent become deformed into
young mountain ranbe I "
b.3' volcanic/magmatic.a.rc within the continental crust
continental-continental,Qonvergence - collision of ilvo
corrtinents ' .::
b.
'I
i
li
,l
':llen{:j11.1. :l ,: l:,
' ' : rrii":ii. ,' r'nl.iil;tu':'l:i:'i
, .,1:. r
,: :
r., :lr,:':it i
c.1 rnar-l<ed by sutr-rre zones (olci sites of subduction)c.2 majestically high mountain ranges in the interior'of
.aneWlargercontinerr:t(e.g.lndiaandAsia)c.3 marked by broad belt of shallow focus earthquakes
ali-,,1-l g the n u me[ousi:far-r lts
i':
3. -fransforil Bounrdaries iiiit::
marked by shailow focus eatfhqLiakes,rl:l:
- first motion studies indicateiil$trike-slip movement
ifi
What Causes ptate motions? 'itiilll
a. mantle convection - involves nCiO'con\ielJtion cells anr:i hotmantle rock ii'
,, due to: ilio a.1 magrna intrusionri on the ridge brest.prrshing tlre
plates ,.o a-? currents mov-ing away carry the plates
*"Push i-iypothesis" :1.
:
"difficurlt to account for the ve'pical.cracks in the rift zonei
b. sitbdt-rction pulls the plates :
*"Pull Flypothesis"
Ir\.
"nan account.for the tensional cracks but in.some ridgesthere are no trenches
i'r1....plurnes and hotspots ll*plumes - narrow colLtmns of hot mantle rock that rise anci
spreacl radially outwald formiiig hotspots of active volcarrismex. plurne under Hawaii
C.
, i{i,,,t$ii:jr
$'.i$,,$,
.ii:'. ,$',
,i it'',:' ii
iii,:
$ii
i;,,,.;,,',tr' :',j':.',:'.:.: t,
. , ,iri)lli
r:.l.1,:l
..