1. rock-forming minerals-an overview.ppt

8/20/2019 1. Rock-forming minerals-An overview.ppt

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Rock-forming minerals:Rock-forming minerals:

An overview An overview

Dr. Arifudin IdrusDr. Arifudin Idrus

Department of Geological EngineeringDepartment of Geological EngineeringGadjah Mada Uniersit! " I#D$#E%IAGadjah Mada Uniersit! " I#D$#E%IA

E-mail address:E-mail address: [email protected] [email protected]


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Introduction:

let back to basic concept!


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What is a mineral?What is a mineral?

• naturally forming

• inorganic

• crystalline solid

• known chemical composition

• known physical properties


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How do Minerals form?How do Minerals form?• Precipitation from a fluid like H2O or CO2.

This can take place within the earth bhdrothermal processes! dia"enesis! andmetamorphism! and at or near the #arth$ssurface as a result of e%aporation! weatherin"!or biolo"ical acti%it.

• &ublimation from a %apor. This process issomewhat more rare! but can take place at a%olcanic %ent! or deep in space where thepressure is near %acuum.


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• Crstalli'ation from ma"ma. This takesplace durin" crstalli'ation of molten

rock (ma"ma) either below or at the#arth$s surface.

• &olid * &olid reactions. This processin%ol%es minerals reactin" with otherminerals in the solid state to produceone or more new minerals. &uch

processes take place durin"metamorphism and dia"enesis due tochan"in" temperature and pressureconditions.


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Composition of the CrustComposition of the Crust• The #arth$s crust is made up of about +,-

i"neous and metamorphic rocks! - shale!/.0,- sandstone! and /.2,- limestone.

• The continental crust has an a%era"ecomposition that appro1imates "ranodiorite (a

medium to siliceous i"neous rock)! whereas

the oceanic crust has an a%era"e composition

that is basaltic (a low silica i"neous rock).


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%era"e composition of the continental crust (Clarke %era"e composition of the continental crust (Clarkeand Washin"ton! 3+2)and Washin"ton! 3+2)


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& 'ecause of the aerage composition of

the crust( the most common minerals

found in the crust are silicates and

o)ides.

& $f the silicates( the aluminosilicates( like

the feldspars and cla! minerals are the

most common.


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& $ther minerals( containing the otherelements in the periodic ta*le are foundin the crust.

& 'ut( in order for these minerals to occur(special geologic conditions are necessar!to concentrate these less a*undantelements so that the! occur in highenough concentrations to form a separatemineral.

& Elements that occur in concentrations lessthan a*out +., usuall! measured inparts per million or parts per *illion/ arecalled dispersed elements or trace

elements.


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0late 1ectonic " Rock Genesis0late 1ectonic " Rock Genesis

3. Mid*ocean 4id"es

2. 5ntracontinental 4ifts

6. 5sland rcs

. cti%e Continental Mar"ins

5.5. Back-arc BasinsBack-arc Basins

6.6. Ocean Island BasaltsOcean Island Basalts

7.7. Miscellaneous Intra-Miscellaneous Intra-

Continental ActivityContinental Activity

kimberlites, carbonatites,kimberlites, carbonatites,anorthosites...anorthosites...


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Diagram of the Interior ofthe EarthCrust

0 to 40 km 0°C

Upper Mantle40 to 670 km

1,000°C

Lower Mantle670 to 2,890 km

2,000°C

Outer Core2,890 to 5,150 km

3,700°C

Inner Core5,150 to 6,370 km

4,300°C


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The #arth7s 5nterior The #arth7s 5nterior Crust8

Oceanic crustThin8 3/ km

4elati%el uniform strati"raph

9 ophiolite suite8

• &ediments

• pillow basalt

• sheeted dikes

• more massi%e "abbro

• ultramafic (mantle)

Continental Crust

Thicker8 2/*+/ km a%era"e :6, km

Hi"hl %ariable composition

; %era"e : "ranodiorite


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he !arth"s Interior he !arth"s Interior

Mantle#Mantle#

$eridotite %ultrama&ic'$eridotite %ultrama&ic'

())er ())er to *+ km %olivineto *+ km %olivine →→ s)inel's)inel'

o /elocity ayer o /elocity ayer 6-00 km6-00 km

ransition 1oneransition 1one as velocity increases 2 ra)idlyas velocity increases 2 ra)idly

*+-66 km*+-66 km

s)inels)inel→→

)erovskite-ty)e )erovskite-ty)e

3i3iI/I/ →→ 3i3i/I/I

oer Mantleoer Mantle has more 4radualhas more 4radual

velocity increasevelocity increase

Figure 1-2. Maor subdivisions o& the !arth.

inter %0+' An Introduction to I4neous andMetamor)hic $etrolo4y. $rentice all.


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he !arth"s Interior he !arth"s Interior

Core#Core#

8e-9i metallic alloy8e-9i metallic alloy

Outer CoreOuter Core is li:uidis li:uid 9o 3-aves 9o 3-aves

Inner CoreInner Core is solidis solid

Figure 1-2. Maor subdivisions o& the !arth.

inter %0+' An Introduction to I4neous andMetamor)hic $etrolo4y. $rentice all.


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Figure 1-5. Relative atomic abundances of the seven most common elements

that comprise 97% of the Earths mass. !n "ntroduction to "gneous and

#etamorphic $etrolog& b 'ohn (inter & $rentice )all.


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.

Minerals make u rocks.

!atura" compounds an#

elements $om%ine toform minerals.

Elements $om%ine to formthe natura" compounds.

Rocks make u the Earth.

&here i' a hierar$h( to thee"ement' of )eo"og(

Atoms make u elements.


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Elements $an %e arrange#, %a'e# on their

i#entifia%"e roertie', into the Periodic Table

Atomic Theor roo'e' that a"" matter i'$omo'e# of the atoms of a%out 100 #ifferent$hemi$a" elements. It further roo'e' that $hemi$a"

compounds are forme# %( the $om%ination of theatom' of #ifferent $hemi$a" e"ement'.


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*n"( ei!htei!ht e"ement' make u o+er "#$ of the earth' $ru't-

M!

%a

&

O

'iAl

(eCa


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The identi)iable characteristics o)The identi)iable characteristics o)

MineralsMinerals arearenaturall occurrin! inor!anic elements or compoundsnaturall occurrin! inor!anic elements or compounds

ha*in! an orderl internal structureha*in! an orderl internal structure

and a characteristic chemical compositionand a characteristic chemical composition+

crstal )orm andcrstal )orm and

phsical properties o) a solidphsical properties o) a solid


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ome RocksRocks are ma#e u of /u't one minera" "ike the 'e#imentar( rock salt ma#e u ofthe minera" ha"ite

*ther' RocksRocks are ma#e u of man(

minera"' "ike the igneou' ro$k !ranite an# the metamorhi$ ro$k !neiss.

MineralsMinerals $om%ine to form$om%ine to form RocksRocks


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M< * The 4ock Ccle in Michi"an * @ebruar 2//3

1. rock-forming minerals-an overview.ppt

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