SMOW Standard Mean Ocean Water

SMOW. standard mean ocean water (a standard for oxygen and hydrogen isotopes)... 

SMOW = Standard Mean Ocean Water IAEA(AgS) = International Atomic Energy Agency (silver sulfide) SMOC = Standard Mean Ocean Chloride... 

These delta values (read delta C-13 , or delta carbon-13 ) are typically given in parts per thousand ( permil , %o). For historical reasons, carbon stable isotopes are reported relative to the PDB (Pee Dee Belemnite, a fossil) or the equivalent VPDB (Vienna PDB) standard. Oxygen and hydrogen stable isotopes are reported relative to SMOW (Standard Mean Ocean Water) or the equivalent VSMOW (Vienna SMOW). The VPDB and VSMOW standards are preferred, not only because the original standards, PDB and SMOW, are no longer available, but also because they imply that the measurements have been calibrated according to international conventions. 

SMOW standard mean ocean water, the reference standard for O isotopes. 

The data are expressed as TR (Tritium Ratio 1 TR corresponds to a H/H ratio of 10 or to an activity concentration of 0.118 Bq/kg water). The data are expressed as percent modem carbon (pmc 100 pmc corresponds to 95% of the NBS oxalic acid standard or to an activity concentration of 0.226 Bq/g C). The and data are expressed as deviations(8-values) relative to SMOW (Standard Mean Ocean Water). The data are expressed as deviations relative to PDB (Pee Dee Belemnite) standard. The data are expressed as /qo deviations relative to CDT (Canion Diablo Troilite) standard. 

SMOW Standard Mean Ocean Water (Vienna)... 

VSMOW for silicates and water. As for PDB, the original SMOW (Standard Mean Ocean Water) material is no longer available. SMOW was defined as... 

Analytically, the separated gases have to be combusted to form CO2 for measurements and the H2O formed is turned into H2, which is measured for D. The standard for carbon isotopes is usually PDB (Peedee Belemnite, a carbonate) though the oil industry also uses the NBS22 (an oil fraction), whereas the standard is SMOW (Standard Mean Ocean Water). 

Isotope ratios in a sample are measured and expressed relative to internationally accepted standard samples of accurately known isotope ratios. For example, PDB (Pee Dee Belemnite CaCOs) is used as a standard for carbon its ratio is 0.0112372 [29]. Similarly, Vienna SMOW (Standard Mean Ocean Water) is the standard for oxygen and hydrogen, and air is the standard for nitrogen. Following are the commonly accepted definitions for reporting isotope ratios ... 

Oxygen SMOW, Standard Mean Ocean Water 180/16Q -2 to +36 -50 to +15... 

Chemical, carbon-isotopic, and oxygen-isotopic compositions from selected samples of the Latrobe dolomite cement are presented in Table 5(A and B). All of the values in Table 5B fall between —10 and —22%o (PDB, Peedee Formation Belemnite). values of the dolomite cement range from 22.7 to 25.2%o (SMOW, Standard Mean Ocean Water) with an... 

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