Onoma: CarilaoV (CarhV) TsikoV Panepisthmio …...Bibliography Sharp, Z. (2007) Principles of Stable...

Onoma: CarilaoV (CarhV) TsikoV

AnaplhrwthV KaqhghthV

Tmhma GewlogiaV

Panepisthmio Rhodes, Grahamstown, RSA

TopoV GennhshV: Aqhna

Hmeromhnia GennhshV: 21/03/1969

SpoudeV: EKPA (BSc); 1986-91

Rhodes (MSc, PhD): 1992-1998

Metadidaktorikh ereuna (1999-2005):

University of Johannesburg

University of Oxford

University of Aberdeen

Pedia ereunaV:

Koitasmatologia Fe/Mn

Gewchmeia staqerwn isotopwn

Biogewchmeia

Pallaioperiballonta

Epikoinwnia: [email protected]

PerissotereV plhroforieV:

http://www.ru.ac.za/primor/people/harilaostsikos

Stable isotopes & palaeoenvironments

Geology 301

Applications of stable

isotope geochemistry

in the geosciences

can be classified into

four main types

Thermometry

(T-dependent

fractionation between

two co-genetic phases)

Palaeoclimatology

(bones, ice and its gas

inclusions, carbonates,

cherts, clays, coal, etc.);

Reaction mechanisms

(open vs closed systems,

diffusion, bacterial-

thermogenic processes,

metabolic pathways)

Tracer studies

(rocks, fluids, plants,

food sources);


The delta value

By convention, stable isotope data are reported as ratios relative to an

international standard, using the d (delta) notation:

d = [(Rx - Rstd) / Rstd] * 1000

where: • R is the ratio of the abundance of the heavy to the light isotope;

• x denotes the sample; and,

• std is the abbreviation for standard.

For the five light elements H, C, O, S and N, R is given by D/H, 13C/12C, 18O/16O, 34S/32S and 15N/14N respectively.

Delta values are reported in per mil (or parts per thousand); the symbol is ‰

The reference standards conventionally used in light stable isotope

geochemistry are: – SMOW, for Standard Mean Ocean Water, for H & O (of fluids and hydrous minerals);

– PDB, for Peedee Belemnite, for C & O (of carbonate minerals);

– CDT, for Canyon Diablo Troilite, for S; and,

– AIR (Atmospheric Nitrogen), for N


O isotope fractionation between selected minerals & H2O as a function of T


103lnaA-B = (a * 106/T2) + b (for high T’s); or

103lnaA-B = (a * 106/T) + b (for low T’s),

where: 103lnaA-B ≈ dA – dB

From: http://www.windows2universe.org/



CO2 + H2O = CH2O + O2 : large negative C isotope fractionation!


Carbon cycle: reservoirs

and isotope signatures


The Cenomanian-Turonian

Oceanic Anoxic Event (OAE2)


Global isotopic anatomy of the Cenomanian-Turonian Oceanic Anoxic Event (OAE2)


Meteoric diagenesis

a. nitrate

5 (CH2O)106(NH3)16(H3PO4) + 472 HNO3 →

276 N2 + 520 CO2 + 5 H3PO4 + 886 H2O

b. manganese oxides

(CH2O)106(NH3)16(H3PO4) + 236 MnO2 + 472 H+ →

236 Mn2+ + 106 CO2 + 8 N2 + H3PO4 + 336 H2O

c. iron oxides

(CH2O)106(NH3)16(H3PO4) + 212 Fe2O3 + 848 H+ →

424 Fe2+ + 106 CO2 + 16 NH3 + H3PO4 + 530 H2O

d. sulphate

(CH2O)106(NH3)16(H3PO4) + 55 SO42- →

106 CO2 + 16 NH3 + 55 S2- + H3PO4 + 106 H2O

e. Methanogenesis (d13C of methane as low as -110 per mil!)


Organic matter diagenesis

Stable isotope records across the Paleocene-Eocene boundary.


Stable isotopes in the

Campanian Mishash

Formation, Israel



Stable isotopes in the hydrological cycle

Vertical d18O section of the Samail ophiolite, Oman


Variations in d13C of atmospheric CO2 as a function of age


Bibliography

Sharp, Z. (2007) Principles of Stable isotope Geochemistry.

Prentice Hall, NJ, 344p.

Additional references

Chester, R. (1993) Marine Geochemistry. Chapman & Hall, London,

698p.

Faure, G. (1998) Principles and Applications of Geochemistry (2nd

Edition). Prentice Hall, NJ, 600p.

Hoefs, J. (2004) Stable Isotope Geochemistry. Springer, Berlin,

244p.

James, R & the Open University Oceanography Course Team

(2005) Marine Biogeochemical Cycles. Open University

Oceanography Series, S330 Volume 5, Elsevier Butterworth-

Heinemann, 130p.


Onoma: CarilaoV (CarhV) TsikoV Panepisthmio …...Bibliography Sharp, Z. (2007) Principles of Stable...

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