Sedimentpetrologie Skript 10 4

8/11/2019 Sedimentpetrologie Skript 10 4

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HvE - Sedimentpetrologie

Pettijohn et al. 1987 p.59

chemical

composition

of common

arenites

(E) Sediment

geochemistry


Herron 1988

Pettijohn 1963, 1987

classification based

on geochemistry


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5%

25%

10%

NCI

CE

NCE

CIsandstones.str.

NCI-bearingsandstone

NCI-richsandstone

hybrida

renite

NCI-be

aring

hybrid

arenite

NCI-rich

hybrid

arenite

calcarenitecalclithite

quartzarenite, arkose, litharenite

glauconitic greensandoolithic ironstonereworked phosphoritegypsarenite

33%

90%

Q

F L incl. CE

ark

ose

quartzarenite

lithic arkose feldspathic

litharenite

litharenitelithic subarkose

sublitharenitesubarkose

2.1.Example:

Swiss

Molasse Basin


on petrography

-1

0

1

0 1 2

quar

tz

arenit

e

arkose

subarkose

sublitharenite

Fe-sandstoneFe-shale

shale

w

acke

litharenite

log(SiO /Al O )2 2 3

lo

g(F

eO

)

2

3/K

O2


on geochemistry

HvE - SedimentpetrologiePettijohn et al. 1987 p.59


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Rollinson 1993


Tectonic Setting Discrimination diagrams

Rollinson 1993 p.208

(1) Major elements:


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discrimination of tectonic setting

by major elementsdoes it work properly ?

Armstron-Altrin & Verma 2005, Sed Geol 177


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Armstron-Altrin & Verma 2005

success rate

be very careful with such discrimination diagrams !!!


the problem of grain-size

Bhatia 1983, Bhatia & Crook 1986, Roser & Korsch 1988

D

C

B

A

A

B

C

D

increasing grain size

greywackes from type-locality Oberharzer Grauwacke

O-g

O-m

O-f

G-g

G-m G-f


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0

10

20

30

40

50

60

0 10 20 30 40

LOI

CaO

0

10

20

30

40

50

60

20 30 40 50 60 70 80

SiO2

CaO

0

4

8

12

16

20

0 10 20 30 40

LOI

MgO

0

4

8

12

16

20

0 10 20 30 40 50 60

CaO

MgO

Bivariate Ca / Mg / LOI-plots of Swiss Molasse sandstones (litharenites)


32 146 578

31

29

27

25

23

21

19

17

15

13

Ma 60%30 0S

32 146 578

31

29

27

25

23

21

19

17

15

13

Ma 60%30 0S

G

WSW ENE


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framework composition vs. wr-geochemistry

von Eynatten 2003



(2) Trace elements:


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McLennan 1993,

GSA Spec Pap 284

detection of various processes

such as recycling, sorting, etc.

Th/Sc monitors the compositional

variation of the source area, andZr/Sc monitors zircon enrichment

due to sedimentary (sorting and)recycling

Acti ve Margi n Turb idi tes

Zr / Sc.1 1 10 100 1000

.1

1

10

.01

.001

Th/Sc

Compositional

varia

tion

Trailing Edge Turbidites

Andean Fo reland

Loess

Sediment

Recycling


% Lu(serpentinite clasts)

group III

group II

group I

recycling

Cr-spinel chemistry

0 0.05 0.10 0.15

2.0

1.5

1.0

0.5

0

TiO2 [Gew.-%]

IPB

IABMORB

FeIII/(Cr+Al+Fe)

0 0.05 0.10 0.15

FeIII/(Cr+Al+Fe)

2.0

1.5

1.0

0.5

0

IPB

IAB

MORB

TiO2 [Gew.-%]

von Eynatten 2003, Sedimentology 50


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SW NEWSW ENE

32 146 578

31

29

27

25

23

21

19

17

15

13

Ma SEDIMENTE

Granitoide

Granitoide

SEDIMENTE

SEDIMENTE

Sedimente

Sedimente

SedimenteGranitoide

Gran

ito

ide

(Ultra-)basite

Se

dim

en

te

(Ultra-)basite

(Ultra-)

basite

(Ultra-)basiteFlysch

Me

tase

dim

en

te

Meta-sedi-mente

> >>

?

~ 21 Ma~ 20 Ma

~ 25 Ma

? recycling ?

? recycling ?

> 75% 50 - 75% 25 - 50% 10 - 25%

WSW ENE

von Eynatten 2003


Contribution of mafic to

ultramafic (ophiolitic)source rocks

( Mixing! )

McLennan 1993


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Rare earth patterns of sediments

from different sources

McLennan 1993

HvE - Sedimentpetrologie Nesbitt & Young 1989

Alteration(weathering, diagenesis, ...)

CIA = 100Al2O3 + CaO* + Na2O + K2O

Al2O3

Chemical Index ofAlteration:

(with CaO* = CaO from silicate phases)

increasing alteration


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Toorongogranodiorite

normalized

to Al2O3 = 1

0

0

1

1 2 3 4 5 6 7 8 9 10

0.2

0.4

0.6

0.8

CaO* Na O2

Al O2 3

K O2

k

von Eynatten et al. 2002, Math. Geol. 34

chemical weathering of granitoid rocks


suspended sediment load of

the worlds major rivers

(McLennan 1993, J. Geol. 101)

s = cc (k pw2)

pw2 = (0.51, 0.13, 0.36)

97.1%

pw1 = (0.49, 0.13, 0.38)

99.5%

chemical weathering at global scales

g

p(A)

p(CN) p(K)

Mackenzie

cc

Orinoco

Indus

Ganges

Danube

St. Lawrence

Niger

Mekong

Congo

river k

St. Lawrence 0.13

Danube 0.25

Ganges 0.75

Indus 0.78

Orinoco 1.01

Mekong 1.87

Congo 2.15

Niger 3.49

von Eynatten et al. 2003, Math. Geol. 35


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Observed trends often due not

correlate with predicted trends

She et al. 2006, Chem Geol.

X1

X2 X3

1

2 ?

a

superposition of processes

von Eynatten 2004, Sed Geol


Trace elements such as Rb, Ba, Sr, U, Th, Zr, etc. may provide valuableadditional information on weathering processes

McLennan 1993

Sedimentpetrologie Skript 10 4

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