The origin of calcium carbonate grains

The origin of calcium carbonate grains

Effects of the CO₂ on the Chemistry of sea water Co₂

sea interface

PH H₂CO₃

Hco₃- Co₃^-2

(H⁺)

Co₃^2-

H₂Co₃ Co₃

pH

pH

pH 7

H⁺ pH

normal sea water pH 7.8

Co₂ pH

HCo₃^-

.)

3( ) 2

2 ( )

3(g H Ol H Co aq

Co  ^

1 .)

( .)

3 ( .)

2 ( .) 3(

2C0 aq H O l HCo aq H aq

H 

 

 ^

2 .)

( .)

2 ( .) 3

2 ( .)

3 (aq H O l Co aq H aq

HCo

 

 



 

acide solution (H2Co₃) basic

solution (Co₃^2-) Carbonate precipitation

Calcium ions (Co₂+)

Carbonate precipitation Carbonate precipitation

Sea water as Acid

dissolved

the carbonate

calcium carbonate precipitation Physo-chemical precipitation reduction of Carbone

dioxide from sea water Carbone dioxide

the carbonate sediments and rocks

dissolve

Organic precipitation shells

dissolved calcium carbonate in sea water

Biochemical precipitation Gas of Carbone dioxide

Photosynthesis

3 2

2

( sed .) H Ca HCo

CaCo 

^{  }



 





 Gco CaCo sed  H

Co

_{2 3 3}

( .)

Oxygen e

Gul Energy

Water Dioxid

Carbon

O O

H C Energy

O H Co





  





 









cos

2 12

2

2

6 6 6 6

6

Carbonate Minerals

Carbonate Minerals

Carbonate Co₃^2-

Carbone and oxygen carbonate groups

minerals common minerals

Rohombohedral Orthohombic

carbonate minerals aragonite

CaCo₃ Calcite

Caco₃

() Dolomite - CaMg(Co₃) Trigonal

Aragonite and calcite chemical composition

CaCo₃)

optical structure aragonite

(orthohombic)

Calcite (Rohombohedral – trigonal system

Diamorphism

Aragonite calcium carbonet orthohombic

X

Hydrochloric acid Stalactites

Calcite calcium carbonate Rohombohedral – trigonal system

X

calcite Marble

calcite Stalactites Stalagmites

Low magnesium

High magnesium calcite

Dolomite Ca,Mg(Co₃) ₂

Dolomitization

(Ca(MgFe)(Co₃)₂

Others minerals

Ca²⁺

Rohombohedral orthoromic

CaSo MgCo

CaCo MgSo

CaCo 





3 3

4

2 3

Carbonate sediments and rocks

Carbonate sediments and rocks carbonate

minerals insitu or intabasinal origin

detrital carbonate particle

Carbonate precipitation environment carbonate saturated water

granuler

crystallize

“direct precipitation”

organic

building Crystals Microcrystallise Carbonate mud (Micrite)

Shallow tropical and

Subtropical Seas

organic or biogenic

Important of carbonate rocks

Limestone rocks

Environmental conditions

Sediments rocks

Fossils

Chemical composition Physio chemical

conditions precipitation

Paleo environment water depth

current

temperature Salinity

Economy important

And Limestone different between Carbonate sediments

Limestone Carbonate sediments

Lithified

mineralogy

<

4

Content of the Carbonate rocks

(Limestone)

Grains Matrix Cement Sparry Calcite

pross Leighton and pendexter

grains

Monominerallic

Skeletal Grains

Non-Skeletal

Coated Grain polygenetic

Ooido

Oolite

Strong bottom current

Superficial

composite (Radial)

Oncoids

pisolite Pisolite

Pellets or Peloids

peloids

faecal gastopods

worms

shrimp

Grain Aggregates microgratall

organic mall Grapestone

lumps botryoidal lumps

Clasts Litiaclasts

lutioclasts

beachrock

hardground

Matrix inorganic

biochemical

Microcrystalline

Micrite Micrite

Matrix

Limestone

Cement

Sparr