nat sci minerals part1

19
! I I I i . :: .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. cornPositicn a. chenric':'l (clefinite but.generally not fixed) b. PtrYsica 4, orderecl aiorni.c ?fl'?rrlerl€flt s. .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'

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Page 1: Nat sci   minerals part1

!

IIIi

. :: .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'

Page 2: Nat sci   minerals part1

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

!

i

I

I

I

I

I

x&

Page 3: Nat sci   minerals part1

A*

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

Page 4: Nat sci   minerals part1

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

Page 5: Nat sci   minerals part1

. 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

Page 6: Nat sci   minerals part1

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

Page 7: Nat sci   minerals part1

,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

Page 8: Nat sci   minerals part1

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

Page 9: Nat sci   minerals part1

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

I

non-metallic minerals (mining): gold district

5.1 Yolungoes ''

!-

: 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

Page 10: Nat sci   minerals part1

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

Page 11: Nat sci   minerals part1

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

Page 12: Nat sci   minerals part1

ffiffi

.. j,::,r. i.:r:.il..l_,'1

:,t,il,i

i+:ir:ri,'i.i;i

!Ii:r;';i'?.ii:li','

!

I

i

I

b9&o'ir 5L)-rr#6p

iiii-ig' btj;iElni.i.'i1.1 Z .E Y

iili$[

6

0,

(sE

E'z

I {}::rl'i':i;l:i+.i

::: olii:i .E r,

l:..ir. 'itr.'..:+i

0)o .c.

6@-rao

o=do)

'7q

LY:t

!i:t

Page 13: Nat sci   minerals part1

,i iii

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

Page 14: Nat sci   minerals part1

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\'

Page 15: Nat sci   minerals part1

'" 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

Page 16: Nat sci   minerals part1

'\.

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

Page 17: Nat sci   minerals part1

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

Page 18: Nat sci   minerals part1

-..

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'

Page 19: Nat sci   minerals part1

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